阅读说明：本技术 喷涂于滚动轴承表面的高性能复合绝缘涂层及其制备方法 (High-performance composite insulating coating sprayed on surface of rolling bearing and preparation method thereof ) 是由 张毅 张志阳 薛启明 田保红 傅丽华 周孟 刘勇 于 2021-06-22 设计创作，主要内容包括：喷涂于滚动轴承表面的高性能复合绝缘涂层,该复合绝缘涂层喷涂于环状滚动轴承内套圈的内圆周表面和外套圈的外圆周表面,包括金属过渡层、陶瓷绝缘层和高分子封闭层,金属过渡层由75wt%的Ni、15wt%的Cr、5wt%的Al和5wt%的Y组构成的合金喷涂而成,陶瓷绝缘层由95-99.5wt%的γ-Al-(2)O-(3)和0.5-5wt%的CeO-(2)组构成的混配粉末喷涂而成,高分子封闭层的原料为呋喃树脂和磺酸类固化剂。本发明适配于普通滚动轴承的,具有结合强度高、韧性强、温度适应范围宽,致密度高等优异性能,能够让电机绝缘轴承在拥有优良机械性能的基础上抵抗轴电流的侵蚀,实用效果较好。(The high-performance composite insulating coating sprayed on the surface of the rolling bearing comprises a metal transition layer, a ceramic insulating layer and a polymer sealing layer, wherein the metal transition layer is formed by spraying an alloy consisting of 75wt% of Ni, 15wt% of Cr, 5wt% of Al and 5wt% of Y, the ceramic insulating layer is formed by 95-99.5wt% of gamma-Al 2 O 3 And 0.5 to 5wt% of CeO 2 The composite material is formed by spraying mixed powder, and the raw materials of the high-molecular sealing layer are furan resin and sulfonic acid curing agent. The invention is suitable for common rolling bearings, has excellent performances of high bonding strength, strong toughness, wide temperature application range, high density and the like, can resist the corrosion of shaft current on the basis of excellent mechanical properties of the motor insulating bearing, and has better practical effect.)

1. The high-performance composite insulating coating sprayed on the surface of the rolling bearing is sprayed on the inner circumferential surface of an inner ring and the outer circumferential surface of an outer ring of the annular rolling bearing, and is characterized in that: the composite insulating coating comprises a metal transition layer, a ceramic insulating layer and a polymer sealing layer which are sequentially attached to the surface of the rolling bearing from inside to outside, wherein the thickness of the metal transition layer is 0.1-0.2mm, the metal transition layer is formed by spraying an alloy consisting of 75wt% of Ni, 15wt% of Cr, 5wt% of Al and 5wt% of Y, the thickness of the ceramic insulating layer is 0.2-1mm, and the ceramic insulating layer is formed by 95-99.5wt% of gamma-Al₂O₃And 0.5 to 5wt% of CeO₂The thickness of the polymer sealing layer is not more than 0.05mm, and the raw materials of the polymer sealing layer are furan resin and sulfonic acid curing agent.

2. The high-performance composite insulating coating sprayed on the surface of the rolling bearing according to claim 1, wherein: the metal transition layer, the ceramic insulating layer and the polymer sealing layer are respectively attached to the surface of the rolling bearing in a high-speed electric arc spraying mode, an atmospheric plasma spraying mode and an air atomization spraying mode.

3. The high-performance composite insulating coating sprayed on the surface of the rolling bearing according to claim 1, wherein: the metal transition layer is made of NiCrAlY metal wire with the diameter of 1.6mm or 2.0 mm.

4. The high-performance composite insulating coating sprayed on the surface of the rolling bearing according to claim 1, wherein: the gamma-Al in the mixed powder₂O₃And CeO₂The purity of (A) is not less than 99.95%.

5. The high-performance composite insulating coating sprayed on the surface of the rolling bearing according to claim 1, wherein: the volume ratio of furan resin to sulfonic acid curing agent in the raw materials of the high-molecular sealing layer is 3: 1.

6. The method for preparing the high-performance composite insulating coating sprayed on the surface of the rolling bearing according to the claim 1 is characterized by comprising the following steps:

step one, adopting a water-based alkaline cleaning agent to perform immersion treatment on a bearing ring of a rolling bearing at the temperature of 70-90 ℃, after the surface of the bearing ring is degreased, transferring the bearing ring into a drying oven at the temperature of 80-120 ℃ to perform drying treatment, and preparing the bearing ring with a clean surface for later use;

secondly, shielding and protecting a non-spraying area of the bearing ring by adopting a clamp with metal end covers at two ends, and then carrying out sand blasting treatment on the area to be sprayed of the bearing ring to obtain the bearing ring with a roughened local surface for later use;

thirdly, a high-speed arc spraying machine is adopted, NiCrAlY metal wire is used as a raw material, and high-speed arc spraying treatment of a region to be sprayed is carried out on the bearing ring with the partially roughened surface in the second step, so that a metal transition layer with the thickness of 0.1-0.2mm is prepared;

step four, respectively weighing 95-99.5wt% of gamma-Al according to the weight percentage₂O₃And 0.5 to 5wt% of CeO₂Mixing to obtain mixed powder, and performing atmospheric plasma spraying on the surface of the metal transition layer by using the prepared mixed powder as a raw material by using an atmospheric plasma spraying machine to form a ceramic insulating layer with the thickness of 0.2-1mm on the surface of the metal transition layer;

step five, mixing furan resin and a sulfonic acid curing agent respectively to prepare a hole sealing agent, and performing air atomization spraying on the surface of the ceramic insulating layer in the step four by using an atomization spraying machine to cure the surface of the ceramic insulating layer to form a polymer sealing layer;

sixthly, grinding the surface excircle of the polymer sealing layer formed by curing in the step five by adopting an excircle grinding machine, so that the thickness of the polymer sealing layer is not more than 0.05 mm;

step seven, cleaning the surface of the bearing ring prepared in the step six by using an ultrasonic cleaner, and then transferring the bearing ring into a drying box at the temperature of 80-120 ℃ for drying treatment to prepare a dried bearing ring for later use;

step eight, carrying out flaw detection inspection on the surface composite insulating coating on the bearing ring prepared in the step seven by using an ultrasonic flaw detector so as to ensure that the bearing ring has no interface crack, internal laminar crack and unsealed cavity defect;

and step nine, according to a bearing assembly standard program, carrying out accessory assembly on the bearing ring subjected to flaw detection inspection in the step eight, and sequentially carrying out quality inspection and packaging treatment on the manufactured finished bearing to obtain the finished motor insulating bearing.

7. The method for preparing the high-performance composite insulating coating sprayed on the surface of the rolling bearing according to claim 6, wherein in the step one, the formula of the water-based alkaline cleaning agent is as follows: 20-30g/L of sodium metasilicate, OP-1010 ml/L of emulsifier and 1L of deionized water.

8. The method for preparing the high-performance composite insulating coating sprayed on the surface of the rolling bearing according to claim 6, wherein the method comprises the following steps: in the second step, the sand blasting treatment is carried out by adopting a self-circulation sand blasting machine, the sand blasting medium during the sand blasting treatment is 16-40 meshes of brown corundum sand, the sand blasting pressure is 0.4-0.6MPa, the sand blasting distance is 100-150mm, the sand blasting angle is 75-85 degrees, the sand blasting time is 5-10 s/ferrule, a step of carrying out high-pressure air blowing impurity removal on the surface of the bearing ferrule is also arranged after the sand blasting treatment, and the subsequent high-speed electric arc spraying treatment needs to be carried out within 4 hours after the sand blasting treatment.

9. The method for preparing the high-performance composite insulating coating sprayed on the surface of the rolling bearing according to claim 6, wherein the method comprises the following steps: in the third step, the spraying voltage during the high-speed electric arc spraying treatment is 36-40V, the spraying current is 180-200A, the spraying distance is 150-200mm, the spraying angle is 80-90 degrees, and the moving speed of the spray gun is 0.2-0.5 m/s.

10. The method for preparing the high-performance composite insulating coating sprayed on the surface of the rolling bearing according to claim 6, wherein the method comprises the following steps: in the fourth step, the arc current during the atmospheric plasma spraying is 500-600A, the arc voltage is 60-80V, and the main gas flow (Ar + N)₂) Is 2-3.6m³H, auxiliary gas flow (H)₂) Is 0.40-0.75m³The spraying distance is 100-150mm, the feeding speed of the granular materials is 30-45g/min, the moving speed of the spray gun is 0.3-0.6m/s, and the spraying angle is 90 degrees.

Technical Field

The invention relates to the technical field of motor insulating bearings, in particular to a high-performance composite insulating coating sprayed on the surface of a rolling bearing and a preparation method thereof.

Background

In recent years, the development of wind power in emerging markets is rapid, and under the background of national policy support and energy supply tension, the wind power in China, particularly the manufacturing industry of wind power equipment, also grows rapidly, and the wind power becomes the most active market of wind power and the manufacturing base of new wind power energy in the world. Wind energy is increasingly gaining attention as a clean renewable energy source in all countries of the world. The wind energy reserve of China is very large and wide in distribution, and the wind energy reserve on the land is only about 2.53 hundred million kilowatts. The world wind market has grown at 40% of the year over the last 5 years. The world wind market is expected to increase 25% annually over the next 20-25 years. With the rapid development of the wind power industry in recent years, the manufacturing technology of domestic large-scale wind generating sets tends to be mature at present, and the key technology of the wind generating sets, namely wind driven generators, monopolized abroad as the core technology of the wind generating sets, becomes a great bottleneck for restricting the development of wind power, wherein induction shaft current ablation often occurs in the use of wind driven generator bearings, and in addition, the offshore wind generating sets also bear harsh ocean atmospheric corrosion, become key factors for seriously restricting the safe operation and the service life of the wind generating sets, and need to be solved urgently. The solution of the problem has important significance for promoting the development of the wind turbine manufacturing industry in our province.

The high speed shaft of the wind turbine runs at 1500 rpm and drives the generator to generate electricity. On modern wind generators, the maximum power output is typically 500 to 12500 kilowatts. When the wind driven generator operates, the potential difference generated between two ends of the rotating shaft or between the shafts is called shaft voltage. If the two ends of the shaft form a loop through a generator base and the like, shaft current is generated under the action of shaft voltage. The shaft current is generated by a closed loop formed by a generator, a bearing, a stator base or an auxiliary device, and because the shaft voltage is lower under normal conditions, a lubricating oil film in the bearing can play an insulating role to inhibit the generation of the shaft current; however, when the shaft voltage is high or the oil film is not stably formed at the moment of starting the generator, the shaft voltage can make the lubricating oil film discharge and break down to form a passage to generate shaft current. In addition, leakage flux due to assembly errors of the generator rotor is a main cause of generation of induced shaft current.

The main measure for preventing and preventing the wind turbine bearing from generating shaft current ablation is to adopt an electric insulation bearing. The insulating bearing can avoid damage caused by electric corrosion, so that the insulating bearing can ensure more reliable operation when being applied to a generator compared with a common bearing. And is more cost effective and reliable than other insulation methods, such as shaft or housing insulation, etc. The external dimension and the basic technical characteristics of the insulated bearing are the same as those of the non-insulated bearing, so that the insulated bearing can be exchanged by one hundred percent and is particularly suitable for offshore and onshore wind generating sets which are difficult to maintain.

The rolling bearing is an important core basic part in mechanical equipment, the quality of the performance of the rolling bearing directly affects the quality, the performance and the reliability of the important equipment and a host machine, and the rolling bearing is often known as a heart part in the mechanical equipment. When current flows through the bearing, a large number of pits with the diameter of only a few microns are formed on the surfaces of the inner and outer raceways and the rolling elements of the bearing due to the discharge effect, so that the friction surface loses luster and even is melted. Bearings operating in this condition quickly fail due to wear, which, in addition to requiring maintenance, entails production losses due to equipment downtime. Although there are several methods known in the prior art for eliminating the current through the bearing, they do not provide a rolling bearing with a higher insulating performance on the basis of having good mechanical properties. The electric erosion is one of common damage forms of the bearing, when current flows through the bearing, the bearing is damaged, the service life of the bearing is greatly shortened, and the bearing can be caused to fail in short days or even hours. Spraying insulating materials on the inner ring and the outer ring of the bearing to prevent current from passing through is an effective method for preventing electric corrosion.

The thermal spraying technology is a method for heating a spraying material to a molten or semi-molten state by utilizing a heat source and spraying and depositing the spraying material on the surface of a pretreated substrate at a certain speed to form a coating, and a special working surface can be manufactured on the surface of a common material to achieve multiple functions of corrosion resistance, wear resistance, friction reduction, high temperature resistance, oxidation resistance, heat insulation, electric conduction and the like. Therefore, how to adopt the thermal spraying technology to provide a high-performance insulating coating for the motor bearing has important industrial application value for prolonging the service life of the rolling bearing.

Disclosure of Invention

The technical purpose of the invention is as follows: the composite insulating coating is suitable for a common rolling bearing, has excellent performances of high bonding strength, strong toughness, wide temperature application range, high density and the like, can resist the corrosion of shaft current on the basis of having excellent mechanical properties of a motor insulating bearing so as to meet the requirement of the bearing on shaft current ablation resistance, and can be simultaneously suitable for wet and dry and high-temperature and low-temperature working environments.

In order to solve the technical problems, the invention adopts the technical scheme that: is sprayed onThe high-performance composite insulating coating on the surface of the rolling bearing is sprayed on the inner circumferential surface of an inner ring and the outer circumferential surface of an outer ring of the annular rolling bearing, and comprises a metal transition layer, a ceramic insulating layer and a high-molecular sealing layer which are sequentially attached to the surface of the rolling bearing from inside to outside, wherein the thickness of the metal transition layer is 0.1-0.2mm, the metal transition layer is formed by spraying an alloy consisting of 75wt% of Ni, 15wt% of Cr, 5wt% of Al and 5wt% of Y, the thickness of the ceramic insulating layer is 0.2-1mm, and the ceramic insulating layer is formed by 95-99.5wt% of gamma-Al₂O₃And 0.5 to 5wt% of CeO₂The thickness of the polymer sealing layer is not more than 0.05mm, and the raw materials of the polymer sealing layer are furan resin and sulfonic acid curing agent.

Preferably, the metal transition layer, the ceramic insulating layer and the polymer sealing layer are respectively attached to the surface of the rolling bearing in a high-speed electric arc spraying mode, an atmospheric plasma spraying mode and an air atomization spraying mode.

Preferably, the raw material of the metal transition layer is NiCrAlY metal wire rod with the diameter of 1.6mm or 2.0mm during spraying.

Preferably, the compound powder contains gamma-Al₂O₃And CeO₂The purity of (A) is not less than 99.95%.

Preferably, the volume ratio of the furan resin to the sulfonic acid curing agent in the raw materials of the polymer sealing layer is 3: 1.

The preparation method of the high-performance composite insulating coating sprayed on the surface of the rolling bearing comprises the following steps:

step one, adopting a water-based alkaline cleaning agent to perform immersion treatment on a bearing ring of a rolling bearing at 70-90 ℃, after the surface of the bearing ring is degreased, transferring the bearing ring into a drying oven at 80-120 ℃ to perform drying treatment, and preparing the bearing ring with a clean surface for later use;

secondly, shielding and protecting a non-spraying area of the bearing ring by adopting a clamp with metal end covers at two ends, and then carrying out sand blasting treatment on the area to be sprayed of the bearing ring to obtain the bearing ring with a roughened local surface for later use;

thirdly, a high-speed arc spraying machine is adopted, NiCrAlY metal wire is used as a raw material, and high-speed arc spraying treatment of a region to be sprayed is carried out on the bearing ring with the partially roughened surface in the second step, so that a metal transition layer with the thickness of 0.1-0.2mm is prepared;

step four, respectively weighing 95-99.5wt% of gamma-Al according to the weight percentage₂O₃And 0.5 to 5wt% of CeO₂Mixing to obtain mixed powder, and performing atmospheric plasma spraying on the surface of the metal transition layer by using the prepared mixed powder as a raw material by using an atmospheric plasma spraying machine to form a ceramic insulating layer with the thickness of 0.2-1mm on the surface of the metal transition layer;

step five, mixing furan resin and a sulfonic acid curing agent respectively to prepare a hole sealing agent, and performing air atomization spraying on the surface of the ceramic insulating layer in the step four by using an atomization spraying machine to cure the surface of the ceramic insulating layer to form a polymer sealing layer;

sixthly, grinding the surface excircle of the polymer sealing layer formed by curing in the step five by adopting an excircle grinding machine, so that the thickness of the polymer sealing layer is not more than 0.05 mm;

step seven, cleaning the surface of the bearing ring prepared in the step six by using an ultrasonic cleaner, and then transferring the bearing ring into a drying box at the temperature of 80-120 ℃ for drying treatment to prepare a dried bearing ring for later use;

step eight, carrying out flaw detection inspection on the surface composite insulating coating on the bearing ring prepared in the step seven by using an ultrasonic flaw detector so as to ensure that the bearing ring has no interface crack, internal laminar crack and unsealed cavity defect;

and step nine, according to a bearing assembly standard program, carrying out accessory assembly on the bearing ring subjected to flaw detection inspection in the step eight, and sequentially carrying out quality inspection and packaging treatment on the manufactured finished bearing to obtain the finished motor insulating bearing.

Preferably, in the step one, the formulation of the water-based alkaline cleaner is as follows: 20-30g/L of sodium metasilicate, OP-1010 ml/L of emulsifier and 1L of deionized water.

Preferably, in the second step, the sand blasting treatment is performed by using a self-circulation sand blasting machine, the sand blasting medium during the sand blasting treatment is 16-40 meshes of brown corundum sand, the sand blasting pressure is 0.4-0.6MPa, the sand blasting distance is 100-150mm, the sand blasting angle is 75-85 degrees, the sand blasting time is 5-10 s/ferrule, a step of performing high-pressure air blowing impurity removal on the surface of the bearing ferrule is further provided after the sand blasting treatment, and the subsequent high-speed arc spraying treatment needs to be performed within 4 hours after the sand blasting treatment.

Preferably, in the third step, the spraying voltage during the high-speed electric arc spraying treatment is 36-40V, the spraying current is 180-.

Preferably, in the fourth step, the arc current during the atmospheric plasma spraying is 500-600A, the arc voltage is 60-80V, and the main gas flow (Ar + N)₂) Is 2-3.6m³H, auxiliary gas flow (H)₂) Is 0.40-0.75m³The spraying distance is 100-150mm, the feeding speed of the granular materials is 30-45g/min, the moving speed of the spray gun is 0.3-0.6m/s, and the spraying angle is 90 degrees.

The invention has the beneficial effects that:

1. the high-performance composite insulating coating formed by multiple layers of composite materials is sprayed on the circumferential surfaces of the inner ring and the outer ring of the bearing, so that the common rolling bearing has good electrical insulating property and insulating strength, and can resist the shaft current corrosion of high-speed motors such as wind power and the like in the service process, thereby avoiding damaging the bearing and lubricating oil, and prolonging the service life and service life of the bearing. Meanwhile, the composite insulating coating has excellent performances of good corrosion resistance, high bonding strength, excellent impact toughness, high density, wide temperature application range, low cost and the like through specific selection and matching of coating materials and improvement of a coating spraying process, and is particularly suitable for severe service environments such as sea, land and the like, and low-temperature environments of tropical high temperature and cold zone. According to the determination, the bonding strength of the composite insulating coating is not less than 15 MPa; the porosity is less than or equal to 5%; the electrical strength is not less than 17 kV/mm; ac limit withstand voltage value: 50Hz, 3000V-5000V;volume resistivity (DC) of 10 or more¹¹Omega m; insulation resistance value: the temperature is 25 +/-2 ℃, and the measurement of DC1000V is more than or equal to 500 MOmega under the condition of normal humidity RH60 +/-3%; the temperature is 150 +/-or more ℃, and the DC1000V is measured to be more than or equal to 100 MOmega under the condition of conventional humidity RH60 +/-3%; under the conditions of room temperature of 25 +/-2 ℃ and high humidity RH95 +/-3%, the DC1000V is measured to be more than or equal to 100 MOmega; the maximum impact energy of the coating is more than or equal to 6.0J; working temperature range: the temperature is-40 to +150 ℃, and the comprehensive performance is excellent.

2. According to the invention, on the structural design of the composite insulating coating, the preparation of the composite insulating coating is carried out by adopting a metal transition layer, a ceramic insulating layer and a polymer sealing layer in a mode of sequentially adhering and overlapping and spraying three layers of structures. The thermal expansion coefficient and the elastic modulus of the ceramic insulating layer and the bearing steel are greatly different, and the design of the metal transition layer can play a role in buffering, so that the thermal stress of a thermal spraying interface between the ceramic insulating layer and the bearing steel and the internal stress of a coating interface caused by the change of the temperature of a use environment are effectively reduced, the bonding strength of the subsequent ceramic insulating layer to be sprayed is improved, the ceramic insulating layer playing a main insulating role is prevented from peeling off, and particularly when the thickness of the ceramic insulating layer is more than 0.3mm, the buffering effect of the metal transition layer is more prominent. The ceramic insulating layer itself is made of gamma-Al₂O₃And CeO₂The two powder materials with different structure phase change characteristics are compounded, and the two powder materials can supplement each other after being attached to the surface of the metal transition layer by thermal spraying, so that the wide adaptability of the composite insulating coating in the process of environmental temperature change and service temperature change is effectively improved, and the composite insulating coating can meet the harsh service environment conditions of sea, land and the like. The polymer sealing layer can effectively plug and fill micro pores generated in the processing of the ceramic insulating layer by adhering to the outer side of the ceramic insulating layer, so that the surface of the ceramic insulating layer is compact, smooth and uniform, and particularly, when the thickness of the ceramic insulating layer is small (for example, the thickness of the ceramic insulating layer is less than 0.3 mm), communication holes between the ceramic insulating layer and the metal transition layer can be effectively avoided, so that the electric resistance (volume resistance, insulation resistance, voltage resistance and the like) of the composite insulating coating is further improved. The composite insulating coating has extremely low porosity and higher porosity under the comprehensive action of layer-by-layer superpositionThe toughness of the composite material can bear the impact load of more than 6J without cracking or peeling, and the composite material has longer service life and excellent comprehensive performance.

3. In the invention, a small amount of CeO is added to the selection of the raw materials of the ceramic insulating layer₂，CeO₂As a rare earth oxide, the rare earth oxide can be rapidly melted into a liquid substance with low viscosity in the process of plasma high-temperature spraying so as to effectively fill gamma-Al with poor melting effect in the ceramic insulating layer₂O₃The cavities among the grain interfaces reduce the surface tension of the ceramic molten drops, reduce the porosity of the ceramic insulating layer and enhance the compactness of the ceramic insulating layer. With CeO₂The addition of the rare earth oxide can also improve the variable range of input power during the construction of the ceramic insulating layer, and has obvious process adaptability.

4. In the invention, Ni, Cr, Al, Y and gamma-Al which are low in price and easy to obtain are selected in the selection of coating preparation raw materials₂O₃And CeO₂And the common materials have large market supply quantity and low price, so that the production cost of the finished insulating bearing is reduced.

5. The preparation process of the motor insulating bearing has simple steps and convenient operation, the processing of the composite insulating coating can be arranged after the finish machining process of the inner bearing ring and the outer bearing ring in the manufacturing process of the common rolling bearing and before the bearing assembling process, the application range is wide, the technical maturity of the coating material and the spraying equipment is high, and the preparation process is suitable for industrial mass production.

6. In the preparation and processing processes of the composite insulating coating, the structural transformation of the ceramic insulating layer between compound raw materials in the plasma spraying process is fully considered and utilized, so that the high-performance electrical insulation characteristic, such as gamma-Al, can be obtained by utilizing cheap materials₂O₃During spraying, the majority of the solution is converted into alpha-Al₂O₃Small fraction of gamma-Al₂O₃Phase retention, Al₂O₃The two-phase structure has different properties, can be rapidly deposited on the surface of the metal transition layer to form a layered structure, further enriches the organization structure in the ceramic insulating layer, reduces the structural transformation internal stress of the coating,and the coating has good self-repairing capability in the spraying process.

Detailed Description

In order to make the technical spirit and advantages of the present invention more clearly understandable to examiners of the patent office and particularly to the public, the applicant shall describe in detail below by way of example, but the description of the embodiments is not intended to limit the technical solution of the present invention, and any equivalent changes made according to the inventive concept, which are merely formal and insubstantial, shall be considered to be within the technical solution of the present invention.

The high-performance composite insulating coating is sprayed on the surface of the rolling bearing, and the composite insulating coating is sprayed on the inner circumferential surface of the inner ring and the outer circumferential surface of the outer ring of the annular rolling bearing and used for blocking current from passing through the inner ring and the outer ring of the bearing. The composite insulating coating comprises a metal transition layer, a ceramic insulating layer and a polymer sealing layer which are sequentially attached to the surface of the rolling bearing from inside to outside, wherein the thickness of the metal transition layer is 0.1-0.2mm, the metal transition layer is made of NiCrAlY metal wire with self-heating reaction, the components of the metal transition layer are Ni 75wt% -Cr15wt wt% -Al 5wt% -Y5 wt%, and the diameter is 1.6mm or 2.0 mm. The thickness of the ceramic insulating layer is 0.2-1mm, and the spraying material of the ceramic insulating layer is gamma-Al with the purity of not less than 99.95 percent₂O₃Powder and CeO with a purity of 99.5%₂Powder of gamma-Al₂O₃ (95-99.5)wt%+CeO₂(0.5-5) wt% and mixing completely. The thickness of the high molecular sealing layer is not more than 0.05mm, the raw materials of the high molecular sealing layer are furan resin and sulfonic acid curing agent with the volume ratio of 3:1, and the high molecular sealing layer is sprayed by air and cured and deposited on the surface of the bearing at room temperature.

The spraying process flow of the composite insulating coating on the surface of the rolling bearing comprises the following steps: 1 degreasing → 2 drying → 3 shielding treatment → 4 sand blasting → 5 high-speed electric arc spraying of a metal transition layer → 6 plasma spraying of a ceramic insulating layer → 7 air atomization spraying of a polymer sealing layer → 8 coating surface grinding → 9 ultrasonic cleaning → 10 drying → 11 coating nondestructive testing → 12 bearing assembly → 13 inspection → 14 packaging and warehousing.

The specific preparation method of the composite insulating coating comprises the following steps:

1. degreasing: the electric heating water tank is used as a degreasing device, and the water-based alkaline cleaning agent is adopted to perform immersion treatment on the bearing ring so as to remove oil pollution caused by machining. The oil stain has strong influence on the bonding strength of the coating. The formula of the water-based alkaline cleaning agent comprises: 20-30g/L of sodium metasilicate, 1% by volume of emulsifier OP-10 and 1000ml of deionized water. The water-based alkaline cleaning agent is used at the temperature of 70-90 ℃ and is soaked for 5-10 min. And (4) after the degreasing is finished, checking the degreasing effect by a water-hanging method, and if a water film is continuously distributed on the surface of the bearing ring, indicating that the bearing ring is cleaned.

2. Drying: drying at 80-120 deg.C in an electric heating constant temperature hot air drying oven to remove residual water stain after degreasing.

3. Shielding treatment: the non-spraying area of the bearing ring is shielded, two sides of the bearing ring are protected by a clamp with metal end covers at two ends, each group of 5-10 rings is connected by a threaded mandrel, and the end covers are fixed by nuts.

4. Sand blasting: and carrying out sand blasting treatment on the non-raceway circumferential surfaces of the inner sleeve ring and the outer sleeve ring. The sand blasting is carried out by adopting a closed self-circulation sand blasting machine, the sand blasting medium is 16-40 meshes of brown corundum sand, the sand blasting pressure is 0.4-0.6MPa, the sand blasting distance is 100-150mm, the sand blasting angle is 75-85 degrees, and the sand blasting time is 5-10 s/ferrule. Sand blasting effect: meanwhile, the method has the effects of removing rust, roughening the surface and increasing the bonding strength of the coating interface. After the sand blasting treatment, the surface of the substrate should be cleaned by dry high-pressure air to blow off residual sand grains and floating dust on the surface, and then the substrate is placed in a clean environment to avoid the surface from being polluted and oxidized by water and impurities in the air. The thermal spraying must be performed within 4 hours after the blasting.

5. High-speed electric arc spraying of a metal transition layer: high-speed electric arc spraying is required to be carried out within 2 hours after the sand blasting is finished, a high-speed electric arc spraying machine is adopted for spraying, a NiCrAlY metal wire rod is used as a raw material, the components of the NiCrAlY metal wire rod are Ni 75wt% -Cr15wt wt% -Al 5wt% -Y5 wt%, and the specification is that the diameter is 1.6mm or 2.0 mm. The technological parameters of high-speed electric arc spraying are as follows: the spraying voltage is 36-40V, the spraying current is 180-200A, the spraying distance is 150-200mm, the spraying angle is 80-90 degrees, and the moving speed of the spray gun is 0.2-0.5 m/s. The thickness of the metal transition layer is 0.1-0.2 mm. In the electric arc spraying process, Cr and Al in the NiCrAl alloy can perform exothermic reaction with the oxide on the surface of the bearing ring, so that the dual effects of removing residual oxide films on the surface and increasing the temperature of the substrate are achieved, and the bonding strength between the transition layer and the substrate is improved.

6. Plasma spraying of the ceramic insulation layer: directly spraying a ceramic insulating layer on the metal transition layer, wherein the spraying material of the ceramic insulating layer is gamma-Al with the purity of not less than 99.95 percent₂O₃Powder and CeO with purity not lower than 99.5%₂Powder of gamma-Al₂O₃ (95-99.5)wt%+CeO₂(0.5-5) wt% and mixing completely. Spraying by adopting an atmospheric plasma spraying machine, wherein the process parameters of the plasma spraying are as follows: plasma arc current 500-600A, arc voltage 60-80V, main gas flow (Ar + N)₂)2-3.6m³H, auxiliary gas flow (H)₂）0.40-0.75m³The spraying distance is 100-150mm, the powder feeding speed is 30-45g/min, the moving speed of the spray gun is 0.3-0.6m/s, the spraying angle is 90 degrees, and the thickness of the coating is 0.2-1 mm. Gamma-Al in the spraying process₂O₃Melting the powder, depositing on the surface of the bearing ring at high speed, and cooling to obtain alpha-Al₂O₃Phase, minor portion remaining as gamma-Al₂O₃And forming a layered ceramic insulating layer.

7. Air atomization spraying of the polymer sealing layer: when the sprayed ceramic insulating layer is still warm, the hole sealing agent is sprayed on the surface of the ceramic insulating layer in time, and the open pores on the surface of the ceramic insulating layer are filled, so that the sealing effect is achieved. The hole sealing agent material is furan resin and sulfonic acid curing agent, and the adding volume ratio is 3: 1. Spraying the mixture on the surface of the ceramic insulating layer by adopting a common mechanical spray coating method, standing at room temperature for 10min, taking out, and standing for 10 hours to obtain the final product which can be completely cured.

8. Grinding the surface of the coating: and (3) firstly, carrying out surface coarse grinding on the polymer sealing layer formed by curing in the step (7) by using a coarse grinding wheel with diamond sand, and then carrying out fine grinding by using a fine grinding wheel with a silicon carbide grinding wheel to ensure that the thickness of the polymer sealing layer is not more than 0.05mm so as to meet the set requirement.

9. Ultrasonic cleaning: and cleaning by using an ultrasonic cleaning machine, cleaning for 1-5 minutes by using deionized water as a cleaning medium, and removing solid particles adhered to the surface of the ferrule and the coating after grinding.

10. Drying: drying at 80-120 deg.C in an electrothermal constant-temperature hot air drying oven to remove residual water stain after ultrasonic cleaning.

11. Nondestructive detection of the coating: and (3) carrying out flaw detection inspection on the surface composite insulating coating of the bearing ring prepared in the step (10) by using an ultrasonic flaw detector to ensure that the surface and the sub-surface of the bearing ring have no defects such as interface cracking, internal laminar cracks, unsealed holes and the like.

12. Assembling a bearing: and assembling according to the common bearing assembling standard procedure, and paying attention to not damage the composite insulating coating on the non-raceway surface of the bearing ring.

13. And (4) checking: and (4) inspecting the bearing finished product according to the technical standards of enterprises or countries. Due to the particularity of the electric insulation rolling bearing, 100% of inspection is required, and the electric insulation rolling bearing is packaged after being qualified.

14. Packaging and warehousing: according to the size of the electric insulation rolling bearing, single piece or multiple pieces are boxed and packaged, and rust prevention and anti-collision protection are well performed.

Compared with the prior art, the composite insulating coating material and the preparation method thereof are simple and feasible, can be placed after the finish machining process of the inner bearing ring and the outer bearing ring in the manufacturing process of the common motor bearing and before the bearing assembling process, and have high technical maturity of the coating material and spraying equipment. The metal-ceramic composite coating is sprayed on the non-raceway part of the inner ring and the outer ring of the bearing, so that the rolling bearing has good electrical insulation and insulating strength, can resist the shaft current corrosion of the motor, particularly the high-speed motor bearing of a fan in service, and avoids damaging the bearing and lubricating oil. In addition, the preparation technology provided by the invention is suitable for industrial batch production.

Example 1

The high-performance composite insulating coating sprayed on the surface of the rolling bearing is formed by processing composite insulating coatings on the inner circumferential surface and the outer circumferential surface of a common bearing, wherein the composite insulating coatings comprise composite insulating coatings sequentially attached from inside to outsideThe metal transition layer, the ceramic insulating layer and the polymer sealing layer are arranged on the surface of the bearing, wherein the thickness of the metal transition layer is 0.1mm, the metal transition layer is made of NiCrAlY metal wire rods with the specification of diameter of 1.6mm and the components of 75wt% of Ni, 15wt% of Cr, 5wt% of Al and 5wt% of Y; the thickness of the ceramic insulating layer is 0.3mm, and the material is gamma-Al with the purity not lower than 99.95 percent₂O₃Powder and CeO₂Powder, and the proportioning relationship between the two is 97wt% of gamma-Al₂O₃And 3wt% of CeO₂(ii) a The thickness of the polymer sealing layer is 0.05mm, and the material is furan resin and methanesulfonic acid with the volume ratio of 3: 1.

The specific preparation method comprises the following steps:

1. degreasing: the electric heating water tank is filled with water-based alkaline cleaning agent with the formula of 25g/L sodium metasilicate, emulsifier OP-10 (the dosage is 1% by volume) and 1000ml deionized water, the electric heating water tank is started, the temperature of the water-based alkaline cleaning agent in the electric heating water tank is raised to 80 ℃, the bearing ring is put into the electric heating water tank for immersion and deoiling treatment, and the immersion time is 10 min. And (4) after the degreasing is finished, checking the degreasing effect by a water-hanging method, and if a water film is continuously distributed on the surface of the bearing ring, indicating that the bearing ring is cleaned.

2. Drying: and drying by adopting an electric heating constant-temperature hot air drying box at the drying temperature of 100 ℃, and drying residual water stains after the degreasing process.

3. Shielding treatment: the non-spraying area of the bearing ring is shielded, two sides of the bearing ring are protected by a clamp with metal end covers at two ends, each group of 5-10 rings is connected by a threaded mandrel, and the end covers are fixed by nuts.

4. Sand blasting: and carrying out sand blasting treatment on the non-raceway sides of the inner ring and the outer ring of the bearing ring by adopting a closed self-circulation sand blasting machine. The sand blasting medium during the treatment is 30-mesh brown corundum sand, the sand blasting pressure is 0.6MPa, the sand blasting distance is 100mm, the sand blasting angle is 80 degrees, and the sand blasting time is 7 s/ferrule. After the sand blasting treatment, the residual sand grains and floating dust on the surface of the matrix are blown off by using dry and clean high-pressure air, then the matrix is placed in a clean environment to avoid the surface from being polluted and oxidized by moisture and impurities in the air, and the thermal spraying is carried out within 4 hours after the sand blasting.

5. High-speed electric arc spraying of a metal transition layer: adopting a high-speed electric arc spraying machine, carrying out high-speed electric arc spraying within 2 hours after the sand blasting treatment is finished, taking a NiCrAlY metal wire rod with the diameter of 1.6mm as a raw material during spraying, and setting process parameters as follows: the spraying voltage is 37V, the spraying current is 190A, the spraying distance is 160mm, the spraying angle is 80 degrees, the moving speed of a spray gun is 0.5m/s, and the metal transition layer with the thickness of 0.1mm is obtained by spraying.

6. Plasma spraying of the ceramic insulation layer: adopting gamma-Al with the purity not lower than 99.95 percent₂O₃Powder and CeO with purity not lower than 99.5%₂The powder is used as raw material according to 97wt% of gamma-Al₂O₃ +3wt%CeO₂The mixed powder is obtained by fully mixing the components in the ratio, an atmospheric plasma spraying machine is adopted, and the set technological parameters are as follows: plasma arc current 500A, arc voltage 70V, main gas flow (Ar + N)₂)2.6m³H, auxiliary gas flow (H)₂）0.65m³The spraying distance is 100mm, the powder feeding speed is 40g/min, the moving speed of the spray gun is 0.5m/s, the spraying angle is 90 degrees, and the ceramic insulating layer with the thickness of 0.3mm is obtained by spraying.

7. Air atomization spraying of the polymer sealing layer: taking furan resin and methanesulfonic acid in a volume ratio of 3:1, adopting a common mechanical spray coating method, spraying a hole sealing agent on the surface of the ceramic insulating layer when the residual temperature of the ceramic insulating layer still exists, standing at room temperature for 10min, taking out, and standing for 10 h to completely cure the hole sealing agent.

8. Grinding the surface of the coating: and (3) carrying out excircle grinding on the surface of the coating subjected to hole sealing treatment by using a silicon carbide fine grinding wheel to enable the thickness of the polymer sealing layer to be a set value.

9. Ultrasonic cleaning: and cleaning by using an ultrasonic cleaning machine, cleaning for 1-5 minutes by using deionized water as a cleaning medium, and removing solid particles adhered to the surface of the ferrule and the coating after grinding.

10. Drying: drying at 80-120 deg.C in an electrothermal constant-temperature hot air drying oven to remove residual water stain after ultrasonic cleaning.

11. Nondestructive detection of the coating: and (3) carrying out flaw detection inspection on the surface composite insulating coating on the bearing ring prepared in the step (10) by using a UT-500 type ultrasonic flaw detector so as to ensure that the surface and the sub-surface of the bearing ring have no defects such as interface cracking, internal laminar cracks, unsealed holes and the like.

12. Assembling a bearing: and assembling according to the common bearing assembling standard procedure, and paying attention to not damage the composite insulating coating on the non-raceway surface of the bearing ring.

13. And (4) checking: and (4) inspecting the bearing finished product according to the technical standards of enterprises or countries. Due to the particularity of the electric insulation rolling bearing, 100% of inspection is required, and the electric insulation rolling bearing is packaged after being qualified.

14. Packaging and warehousing: according to the size of the electric insulation rolling bearing, single piece or multiple pieces are boxed and packaged, and rust prevention and anti-collision protection are well performed.

The performance of the composite insulating coating prepared in the embodiment is measured, and the bonding strength is 22.4 MPa; the porosity is 2.1%; the electrical strength is 20.2 kV/mm; ac limit withstand voltage value: 50Hz, 3900V; volume resistivity (DC) 1.23X 10¹¹Omega m; the impact energy of the coating is 9.5J; working temperature range: minus 40 ℃ to plus 150 ℃.

Example 2

The high-performance composite insulating coating sprayed on the surface of the rolling bearing is formed by processing composite insulating coatings on the inner circumferential surface and the outer circumferential surface of a common bearing, wherein the composite insulating coatings comprise a metal transition layer, a ceramic insulating layer and a polymer sealing layer which are sequentially attached to the surface of the bearing from inside to outside, wherein the metal transition layer is 0.2mm thick and is made of NiCrAlY metal wire rods with the specification of 1.6mm in diameter and the components of 75wt% Ni-15wt% Cr-5wt% Al-5wt% Y; the thickness of the ceramic insulating layer is 0.7mm, and the material is gamma-Al with the purity not lower than 99.95 percent₂O₃Powder and CeO₂Powder, and the proportion relation between the two is 99.5wt% of gamma-Al₂O₃And 0.5wt% of CeO₂B, carrying out the following steps of; the thickness of the polymer sealing layer is 0.05mm, and the material is furan resin and methanesulfonic acid with the volume ratio of 3: 1.

The specific preparation method comprises the following steps:

1. degreasing: the steps are consistent with the example 1, only the adding amount of sodium metasilicate in the water-based alkaline cleaning agent is 22g/L, the temperature during the immersion and deoiling treatment is 70 ℃, and the immersion time is 8 min.

2. Drying: this step was identical to example 1, except that the drying temperature was set to 70 ℃.

3. Shielding treatment: this procedure was in accordance with example 1.

4. Sand blasting: the steps are consistent with the example 1, the sand blasting medium adopted in the sand blasting treatment is 40-mesh brown corundum sand, the sand blasting pressure is 0.5MPa, the sand blasting distance is 100mm, the sand blasting angle is 85 degrees, the sand blasting time is 6 s/ferrule, and the thermal spraying must be carried out within 4 hours after the sand blasting.

5. High-speed electric arc spraying of a metal transition layer: adopting a high-speed electric arc spraying machine, carrying out high-speed electric arc spraying within 2 hours after the sand blasting treatment is finished, taking a NiCrAlY metal wire rod with the diameter of 1.6mm as a raw material during spraying, and setting process parameters as follows: spraying voltage is 36V, spraying current is 180A, spraying distance is 150mm, spraying angle is 90 degrees, moving speed of a spray gun is 0.3m/s, and a metal transition layer with thickness of 0.2mm is obtained through spraying.

6. Plasma spraying of the ceramic insulation layer: gamma-Al with purity of 99.95% is used₂O₃Powder and CeO with purity not lower than 99.5%₂The powder is used as raw material according to the proportion of 99.5wt% of gamma-Al₂O₃ +0.5wt%CeO₂The mixed powder is obtained by fully mixing the components in the ratio, an atmospheric plasma spraying machine is adopted, and the set technological parameters are as follows: plasma arc current 550A, arc voltage 60V, main gas flow (Ar + N)₂)3.2m³H, auxiliary gas flow (H)₂）0.75m³The spraying distance is 120mm, the powder feeding speed is 40g/min, the moving speed of a spray gun is 0.3m/s, the spraying angle is 90 degrees, and the ceramic insulating layer with the thickness of 0.7mm is obtained by spraying.

The subsequent steps 7-14 are all in accordance with example 1.

The performance of the composite insulating coating prepared in the embodiment is measured, and the bonding strength is 22.4 MPa; porosity 1.6%; the electrical strength is 23.5 kV/mm; ac limit withstand voltage value: 50Hz, 5020V; volume resistivity (DC) 1.16X 10¹¹Omega m; the impact energy of the coating is 8.3J; working temperature range: minus 40 ℃ to plus 150 ℃.

Example 3

The true bookThe high-performance composite insulating coating sprayed on the surface of the rolling bearing is prepared by processing composite insulating coatings on the inner circumferential surface and the outer circumferential surface of a common bearing, wherein the composite insulating coatings comprise a metal transition layer, a ceramic insulating layer and a polymer sealing layer which are sequentially attached to the surface of the bearing from inside to outside, the thickness of the metal transition layer is 0.15mm, the metal transition layer is made of NiCrAlY metal wire rods with the specification of 2mm in diameter and the components of 75wt% Ni-15wt% Cr-5wt% Al-5wt% Y; the thickness of the ceramic insulating layer is 0.2mm, and the material is gamma-Al with the purity not lower than 99.95 percent₂O₃Powder and CeO₂Powder, and the proportion relationship between the two is 99wt% of gamma-Al₂O₃And 1wt% of CeO₂B, carrying out the following steps of; the thickness of the polymer sealing layer is 0.04mm, and the material is furan resin and methanesulfonic acid with the volume ratio of 3: 1.

The specific preparation method comprises the following steps:

1. degreasing: the steps are consistent with the example 1, only the addition amount of the sodium metasilicate in the water-based alkaline cleaning agent is 20g/L, the temperature is 90 ℃ when only immersion degreasing treatment is carried out, and the immersion time is 6 min.

2. Drying: this step was identical to example 1, except that the drying temperature was set to 90 ℃.

3. Shielding treatment: this procedure was in accordance with example 1.

4. Sand blasting: the procedure is the same as that of example 1, the sand blasting medium adopted in the sand blasting treatment is 16-mesh brown corundum sand, the sand blasting pressure is 0.4MPa, the sand blasting distance is 110mm, the sand blasting angle is 80 degrees, the sand blasting time is 10 s/ferrule, and the thermal spraying must be carried out within 4 hours after the sand blasting.

5. High-speed electric arc spraying of a metal transition layer: adopting a high-speed electric arc spraying machine, carrying out high-speed electric arc spraying within 2 hours after the sand blasting treatment is finished, taking a NiCrAlY metal wire rod with the diameter of 2mm as a raw material during spraying, and setting process parameters as follows: spraying voltage of 40V, spraying current of 185A, spraying distance of 170mm, spraying angle of 85 degrees and spray gun moving speed of 0.3m/s, and spraying to obtain a metal transition layer with thickness of 0.15 mm.

6. Plasma spraying of the ceramic insulation layer: gamma-Al with purity of 99.95% is used₂O₃Powder and purityNot less than 99.5% of CeO₂The powder is used as raw material according to the proportion of 99wt% of gamma-Al₂O₃ +1wt%CeO₂The mixed powder is obtained by fully mixing the components in the ratio, an atmospheric plasma spraying machine is adopted, and the set technological parameters are as follows: plasma arc current 600A, arc voltage 80V, main gas flow (Ar + N)₂)3m³H, auxiliary gas flow (H)₂）0.40m³The spraying distance is 150mm, the powder feeding speed is 30g/min, the moving speed of a spray gun is 0.6m/s, the spraying angle is 90 degrees, and the ceramic insulating layer with the thickness of 0.2mm is obtained by spraying.

The subsequent steps 7-14 are all in accordance with example 1.

The performance of the composite insulating coating prepared in the embodiment is measured, and the bonding strength is 4100V; volume resistivity (DC) 1.19X 10¹¹Omega m; the impact energy of the coating is 9.2J; working temperature range: minus 40 ℃ to plus 150 ℃.

Example 4

The high-performance composite insulating coating sprayed on the surface of the rolling bearing is formed by processing composite insulating coatings on the inner circumferential surface and the outer circumferential surface of a common bearing, wherein the composite insulating coatings comprise a metal transition layer, a ceramic insulating layer and a polymer sealing layer which are sequentially attached to the surface of the bearing from inside to outside, wherein the metal transition layer is 0.12mm thick and is made of NiCrAlY metal wire rods with the specification of 1.6mm in diameter and the components of 75wt% Ni-15wt% Cr-5wt% Al-5wt% Y; the thickness of the ceramic insulating layer is 1mm, and the material is gamma-Al with the purity not lower than 99.95 percent₂O₃Powder and CeO₂Powder, and the proportion relationship between the two is 98.5wt% of gamma-Al₂O₃And 1.5wt% of CeO₂B, carrying out the following steps of; the thickness of the polymer sealing layer is 0.04mm, and the material is furan resin and methanesulfonic acid with the volume ratio of 3: 1.

The specific preparation method comprises the following steps:

1. degreasing: the steps are consistent with the example 1, the adding amount of sodium metasilicate in the water-based alkaline cleaning agent is only 30g/L, the temperature during the immersion and deoiling treatment is only 75 ℃, and the immersion time is 9 min.

2. Drying: this step was identical to example 1, only the drying temperature was set to 120 ℃.

3. Shielding treatment: this procedure was in accordance with example 1.

4. Sand blasting: the procedure is the same as that of example 1, the sand blasting medium adopted in the sand blasting treatment is 30-mesh brown corundum sand, the sand blasting pressure is 0.5MPa, the sand blasting distance is 150mm, the sand blasting angle is 85 degrees, the sand blasting time is 8 s/ferrule, and the thermal spraying must be carried out within 4 hours after the sand blasting.

5. High-speed electric arc spraying of a metal transition layer: adopting a high-speed electric arc spraying machine, carrying out high-speed electric arc spraying within 2 hours after the sand blasting treatment is finished, taking a NiCrAlY metal wire rod with the diameter of 1.6mm as a raw material during spraying, and setting process parameters as follows: spraying voltage of 38V, spraying current of 190A, spraying distance of 160mm, spraying angle of 80 degrees and spray gun moving speed of 0.5m/s, and spraying to obtain a metal transition layer with thickness of 0.12 mm.

6. Plasma spraying of the ceramic insulation layer: gamma-Al with purity of 99.95% is used₂O₃Powder and CeO with purity not lower than 99.5%₂The powder is taken as a raw material and is based on 98.5wt% of gamma-Al₂O₃ +1.5wt%CeO₂The mixed powder is obtained by fully mixing the components in the ratio, an atmospheric plasma spraying machine is adopted, and the set technological parameters are as follows: plasma arc current 550A, arc voltage 75V, main gas flow (Ar + N)₂) 3.6m³H, auxiliary gas flow (H)₂）0.75m³And h, spraying distance of 130mm, powder feeding speed of 35g/min, spray gun moving speed of 0.4m/s, spraying angle of 90 degrees, and spraying to obtain the ceramic insulating layer with the thickness of 1 mm.

The subsequent steps 7-14 are all in accordance with example 1.

The performance of the composite insulating coating prepared in the embodiment is measured, and the bonding strength is 22.4 MPa; the porosity is 3.2%; the electrical strength is 31.2 kV/mm; ac limit withstand voltage value: 50Hz, 4300V; volume resistivity (DC) 1.29X 10¹¹Omega m; the impact energy of the coating is 6.7J; working temperature range: minus 40 ℃ to plus 150 ℃.

Example 5

The high-performance composite insulating coating sprayed on the surface of the rolling bearing is prepared by processing composite insulating coatings on the inner circumferential surface and the outer circumferential surface of a common bearingThe edge coating comprises a metal transition layer, a ceramic insulating layer and a polymer sealing layer which are sequentially attached to the surface of the bearing from inside to outside, wherein the thickness of the metal transition layer is 0.16mm, the metal transition layer is made of NiCrAlY metal wire rods, the specification of the metal transition layer is 2mm, and the NiCrAlY metal wire rods comprise 75wt% of Ni, 15wt% of Cr, 5wt% of Al and 5wt% of Y; the thickness of the ceramic insulating layer is 0.7mm, and the material is gamma-Al with the purity not lower than 99.95 percent₂O₃Powder and CeO₂Powder, and the proportion relationship between the two is 98wt% of gamma-Al₂O₃And 2wt% of CeO₂B, carrying out the following steps of; the thickness of the polymer sealing layer is 0.02mm, and the material is furan resin and methanesulfonic acid with the volume ratio of 3: 1.

The specific preparation method comprises the following steps:

1. degreasing: the steps are consistent with the example 1, the adding amount of sodium metasilicate in the water-based alkaline cleaning agent is 24g/L, the temperature for immersion and deoiling treatment is 70 ℃, and the immersion time is 8 min.

2. Drying: this step was the same as in example 1, except that the drying temperature was set to 100 ℃.

3. Shielding treatment: this procedure was in accordance with example 1.

4. Sand blasting: the procedure is the same as that of example 1, the blasting medium adopted in the blasting treatment is 35-mesh brown corundum sand, the blasting pressure is 0.4MPa, the blasting distance is 100mm, the blasting angle is 80 degrees, the blasting time is 7 s/ferrule, and the thermal spraying must be carried out within 4 hours after the blasting.

5. High-speed electric arc spraying of a metal transition layer: adopting a high-speed electric arc spraying machine, carrying out high-speed electric arc spraying within 2 hours after the sand blasting treatment is finished, taking a NiCrAlY metal wire rod with the diameter of 2mm as a raw material during spraying, and setting process parameters as follows: spraying voltage is 36V, spraying current is 200A, spraying distance is 200mm, spraying angle is 85 degrees, moving speed of a spray gun is 0.4m/s, and a metal transition layer with thickness of 0.16mm is obtained through spraying.

6. Plasma spraying of the ceramic insulation layer: adopting gamma-Al with the purity not lower than 99.95 percent₂O₃Powder and CeO with a purity of 99.5%₂The powder is taken as a raw material and is prepared according to the proportion of 98wt% of gamma-Al₂O₃ +2wt%CeO₂Mixing to obtain mixed powder, and mixingThe atmospheric plasma spraying machine is characterized in that the process parameters are set as follows: plasma arc current 600A, arc voltage 60V, main gas flow (Ar + N)₂)2m³H, auxiliary gas flow (H)₂）0.6m³The spraying distance is 120mm, the powder feeding speed is 30g/min, the moving speed of a spray gun is 0.5m/s, the spraying angle is 90 degrees, and the ceramic insulating layer with the thickness of 0.7mm is obtained by spraying.

The subsequent steps 7-14 are all in accordance with example 1.

The performance of the composite insulating coating prepared in the embodiment is measured, and the bonding strength is 22.4 MPa; porosity 4.1%; the electrical strength is 23.6 kV/mm; ac limit withstand voltage value: 50Hz, 3500V; volume resistivity (DC) 1.31X 10¹¹Omega m; the impact energy of the coating is 8.1J; working temperature range: minus 40 ℃ to plus 150 ℃.

Example 6

The high-performance composite insulating coating sprayed on the surface of the rolling bearing is formed by processing composite insulating coatings on the inner circumferential surface and the outer circumferential surface of a common bearing, wherein the composite insulating coatings comprise a metal transition layer, a ceramic insulating layer and a polymer sealing layer which are sequentially attached to the surface of the bearing from inside to outside, wherein the metal transition layer is 0.14mm thick and is made of NiCrAlY metal wire rods with the specification of 1.6mm in diameter and the components of 75wt% Ni-15wt% Cr-5wt% Al-5wt% Y; the thickness of the ceramic insulating layer is 0.2mm, and the material is gamma-Al with the purity not lower than 99.95 percent₂O₃Powder and CeO₂Powder, and the proportioning relationship between the two is 95wt% of gamma-Al₂O₃And 5wt% of CeO₂B, carrying out the following steps of; the thickness of the polymer sealing layer is 0.03mm, and the material is furan resin and methanesulfonic acid with the volume ratio of 3: 1.

The specific preparation method comprises the following steps:

1. degreasing: the steps are consistent with the example 1, the adding amount of sodium metasilicate in the water-based alkaline cleaning agent is 27g/L, the temperature for immersion and deoiling treatment is 90 ℃, and the immersion time is 5 min.

2. Drying: this step was identical to example 1, except that the drying temperature was set to 80 ℃.

3. Shielding treatment: this procedure was in accordance with example 1.

4. Sand blasting: the procedure is the same as that of example 1, the blasting medium adopted in the blasting treatment is 20-mesh brown corundum sand, the blasting pressure is 0.6MPa, the blasting distance is 120mm, the blasting angle is 75 degrees, the blasting time is 5 s/ferrule, and the thermal spraying must be carried out within 4 hours after the blasting.

5. High-speed electric arc spraying of a metal transition layer: adopting a high-speed electric arc spraying machine, carrying out high-speed electric arc spraying within 2 hours after the sand blasting treatment is finished, taking a NiCrAlY metal wire rod with the diameter of 1.6mm as a raw material during spraying, and setting process parameters as follows: spraying voltage of 37V, spraying current of 180A, spraying distance of 150mm, spraying angle of 90 degrees, moving speed of a spray gun of 0.2m/s, and spraying to obtain a metal transition layer with thickness of 0.14 mm.

6. Plasma spraying of the ceramic insulation layer: adopting gamma-Al with the purity not lower than 99.95 percent₂O₃Powder and CeO with a purity of 99.5%₂The powder is used as raw material according to the proportion of 95wt% of gamma-Al₂O₃ +5wt%CeO₂The mixed powder is obtained by fully mixing the components in the ratio, an atmospheric plasma spraying machine is adopted, and the set technological parameters are as follows: plasma arc current 550A, arc voltage 80V, main gas flow (Ar + N)₂)2.5m³H, auxiliary gas flow (H)₂）0.5m³The spraying distance is 110mm, the powder feeding speed is 45g/min, the moving speed of a spray gun is 0.3m/s, the spraying angle is 90 degrees, and the ceramic insulating layer with the thickness of 0.2mm is obtained by spraying.

The subsequent steps 7-14 are all in accordance with example 1.

The performance of the composite insulating coating prepared in the embodiment is measured, and the bonding strength is 22.4 MPa; the porosity is 3.9%; the electrical strength is 27.3 kV/mm; ac limit withstand voltage value: 50Hz, 3200V; volume resistivity (DC) 1.17X 10¹¹Omega m; the impact energy of the coating is 7.2J; working temperature range: minus 40 ℃ to plus 150 ℃.

The above examples are provided for clarity of illustration only and are not intended to limit the invention to the particular embodiments described. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And obvious variations or modifications can be made without departing from the scope of the invention as claimed.