阅读说明：本技术 核电大锻件热处理涂料及其配制方法 (Nuclear power heavy forging heat treatment coating and preparation method thereof ) 是由 白敏� 沈国劬 毛闯 孙嫘 陈新倬 于 2020-11-20 设计创作，主要内容包括：本发明涉及核电大锻件热处理涂料及其配制方法,属于核电大锻件热处理涂料领域。核电大锻件热处理涂料由固体粉料和液体组成；所述固体粉料由以下重量份组分组成：石墨烯20～50份、硅酸钠10～50份、铝粉10～20份、高岭土5～18份、磷酸二氢钙5～30份和三氧化二硼18～35份；所述液体由以下重量份组分组成：水溶性酚醛树脂1～10份、有机硅偶联剂0.1～1.5份和水50～100份。本发明的涂料,抗氧化效果优良,可以对核电锻件在1200℃及以上温度下多次锻造加热时提供方便的抗氧化保护,涂料在锻件表面涂施速度快,使用方便,容易成膜,无温度限制,长时间的加热过程造成的氧化增重减少95％以上。(The invention relates to a nuclear power heavy forging heat treatment coating and a preparation method thereof, belonging to the field of nuclear power heavy forging heat treatment coatings. The nuclear power heavy forging heat treatment coating consists of solid powder and liquid; the solid powder consists of the following components in parts by weight: 20-50 parts of graphene, 10-50 parts of sodium silicate, 10-20 parts of aluminum powder, 5-18 parts of kaolin, 5-30 parts of monocalcium phosphate and 18-35 parts of boron trioxide; the liquid consists of the following components in parts by weight: 1-10 parts of water-soluble phenolic resin, 0.1-1.5 parts of organic silicon coupling agent and 50-100 parts of water. The coating disclosed by the invention is excellent in oxidation resistance effect, can provide convenient oxidation resistance protection for nuclear power forgings when being forged and heated for multiple times at the temperature of 1200 ℃ or above, is high in coating speed on the surfaces of the forgings, convenient to use, easy to form films, free of temperature limitation, and capable of reducing the oxidation weight gain caused by a long-time heating process by more than 95%.)

1. The nuclear power heavy forging heat treatment coating is characterized by comprising solid powder and liquid;

the solid powder consists of the following components in parts by weight: 20-50 parts of graphene, 10-50 parts of sodium silicate, 10-20 parts of aluminum powder, 5-18 parts of kaolin, 5-30 parts of monocalcium phosphate and 18-35 parts of boron trioxide;

the liquid consists of the following components in parts by weight: 1-10 parts of water-soluble phenolic resin, 0.1-1.5 parts of organic silicon coupling agent and 50-100 parts of water.

2. The heat treatment coating for the nuclear power heavy forging as claimed in claim 1, wherein the fineness of graphene is greater than 1200 meshes, the fineness of sodium silicate is greater than 80 meshes, the fineness of aluminum powder is greater than 200 meshes, the fineness of kaolin is greater than 320 meshes, the fineness of monocalcium phosphate is greater than 320 meshes, and the fineness of boron trioxide is greater than 70 meshes.

3. The nuclear power heavy forging heat treatment coating as claimed in claim 1, wherein the aluminum content in the aluminum powder is more than or equal to 99.5%.

4. The nuclear power heavy forging heat treatment coating as claimed in claim 1, wherein the coating is composed of solid powder and liquid;

the solid powder consists of the following components in parts by weight: 28-40 parts of graphene, 17-35 parts of sodium silicate, 10-15 parts of aluminum powder, 5-10 parts of kaolin, 12-20 parts of monocalcium phosphate and 20-25 parts of boron trioxide;

the liquid consists of the following components in parts by weight: 1.5-2.5 parts of water-soluble phenolic resin, 0.1-0.2 part of organic silicon coupling agent and 60-65 parts of water.

5. The nuclear power heavy forging heat treatment coating as claimed in claim 1, wherein the solid powder comprises the following components in parts by weight: 30-40 parts of graphene, 20-35 parts of sodium silicate, 12-15 parts of aluminum powder, 5-10 parts of kaolin, 12-20 parts of monocalcium phosphate and 20-21 parts of boron trioxide;

the liquid consists of the following components in parts by weight: 2-2.2 parts of water-soluble phenolic resin, 0.1-0.2 part of organic silicon coupling agent and 60-65 parts of water.

6. The nuclear power heavy forging heat treatment coating as claimed in claim 5, wherein the solid powder comprises the following components in parts by weight: 30-40 parts of graphene, 20-35 parts of sodium silicate, 15 parts of aluminum powder, 10 parts of kaolin, 12-20 parts of monocalcium phosphate and 20-21 parts of boron trioxide.

7. The nuclear power heavy forging heat treatment coating as claimed in claim 6, wherein the solid powder comprises the following components in parts by weight: 40 parts of graphene, 35 parts of sodium silicate, 15 parts of aluminum powder, 10 parts of kaolin, 20 parts of monocalcium phosphate and 21 parts of boron trioxide;

the liquid consists of the following components in parts by weight: 2 parts of water-soluble phenolic resin, 0.1 part of organic silicon coupling agent and 60 parts of water.

8. The preparation method of the nuclear power heavy forging heat treatment coating is characterized by comprising the following steps of: uniformly dispersing the solid powder and the liquid according to any one of claims 1 to 7, and sanding for at least 60min after the dispersion is finished.

9. The preparation method of the nuclear power heavy forging heat treatment coating as claimed in claim 8, wherein the viscosity of the coating is 130-140 Be ° at room temperature.

10. The use method of the nuclear power heavy forging heat treatment coating is characterized in that the nuclear power heavy forging heat treatment coating as claimed in any one of claims 1-7 is directly sprayed on the surface of a forging, and the coating thickness is more than or equal to 0.5 mm.

Technical Field

The invention relates to a nuclear power heavy forging heat treatment coating and a preparation method thereof, belonging to the field of nuclear power heavy forging heat treatment coatings.

Background

The forging is made of medium and low alloy steel such as SA508 and 18MND5, and the medium and low alloy steel is seriously oxidized at high temperature in the heat treatment and forging heating processes. How to protect them from oxidation or as little as possible during high temperature heat treatment, especially at temperatures of 1200 c and above, is a constant goal pursued by the equipment manufacturing industry. The free energy of the oxidation reaction process of the steel at the temperature of 1200 ℃ and above is reduced, and the reduction amplitude is increased along with the increase of the temperature; the high-temperature corrosion is very serious, which not only causes great waste, but also causes great difficulty for manufacturing products. In order to avoid oxidation corrosion during the heating of steel, the most effective methods developed at present are to control the atmosphere in the heat treatment furnace and to apply a protective coating to the heated steel surface, in addition to selecting a material resistant to high temperature thermal oxidation. Because the control of the atmosphere in the heat treatment furnace is restricted by various factors, such as the size, the sealing, the material of the furnace body and the like of the heating furnace; the use of protective coatings is therefore the most realistic and convenient choice in the actual production process.

As mentioned above, although a lot of researches have been conducted for a long time at home and abroad on the prevention of oxidation in the heating process of steel and mechanical products, a method for preventing oxidation by using a coating conveniently is also provided. However, the actual effect of the current anti-oxidation coating is far from the requirements of people. The materials with obvious antioxidation effect of the coating are stainless steel and high-temperature alloy thereof, and the heat treatment temperature with obvious effect is usually below 1100 ℃. In the manufacturing process of heavy equipment, particularly nuclear power equipment, heat treatment of the medium-low alloy steel at high temperature for more than tens of hours is indispensable, so that the solution of oxidation resistance under the condition is of great significance.

However, the information data of the antioxidant coating for heat treatment of steel parts disclosed at present has several defects, for example, the applicable temperature of the high temperature resistant coating disclosed in the Chinese patent application No. 99114492.9 "an inorganic high temperature resistant coating and its preparation method" is 650 ℃. In view of the above-mentioned drawbacks, many high-temperature metal oxidation-resistant coatings with higher applicable temperature have been developed and disclosed, such as "a metal heat treatment protective coating" in chinese patent application No. 201610385703.X ", application No. 201611119022.5" a common oxidation-resistant coating and its use method "application No. 201810678051.8" a high-temperature oxidation-resistant coating for heat treatment of carbon steel and its preparation method "and the like, which all have the disadvantages of long construction period, poor actual oxidation-resistant effect, etc., or these oxidation-resistant coatings have short heat treatment oxidation protection time, and in the manufacturing process of heavy equipment, especially nuclear power equipment, heat treatment of medium-low alloy steel for more than tens of hours at high temperature is essential, so that it has very important meaning to solve oxidation resistance under such circumstances.

In addition, the existing high-temperature-resistant antioxidant coating also has various defects, such as easy precipitation and agglomeration of solid components in the antioxidant coating, difficult uniform mixing in use and unobvious antioxidant effect; and some anti-oxidation coatings need to treat the surface of steel before use and are difficult to remove after use.

CN102585568A discloses a heat treatment antioxidant coating for steel and a preparation method thereof, wherein the coating comprises solid powder and liquid: the solid powder comprises the following components in parts by weight: 30-50 parts of glass powder, 10-50 parts of boron nitride, 2-5 parts of chromium trioxide and 3-10 parts of metal aluminum powder; the liquid comprises the following components in parts by weight: 0.1-5 parts of modified magnesium aluminum silicate, 20-35 parts of organic silicon resin and 100 parts of dimethylbenzene. The coating takes glass powder as a main component for heat treatment and oxidation resistance, and the main function of the glass powder is mainly isolation of a melt at a high temperature.

CN110330819A discloses an antioxidant coating, which is a solid powder coating and consists of the following materials in parts by weight: 30-50 parts of colloidal graphite powder, 30-50 parts of sodium silicate, 10-20 parts of iron powder, 5-15 parts of aluminum powder, 5-18 parts of kaolin, 10-30 parts of mica powder and 18-35 parts of boron trioxide. The coating is a solid coating, is mainly suitable for the forged piece which is processed in a heating furnace, and is required to be re-melted and heated for a plurality of times due to the process, so that the temperature of the forged piece is very high, such as above 900 ℃, and the temperature is not suitable for being reduced to the normal temperature and then coated with the protective coating.

Disclosure of Invention

The invention solves the first technical problem by providing a heat treatment coating for a nuclear power heavy forging. The paint uses water-soluble phenolic resin as a binder and a dispersant, and solid powder contains a plurality of inorganic substances with excellent oxidation resistance at high temperature.

The nuclear power heavy forging heat treatment coating comprises solid powder and liquid;

the solid powder consists of the following components in parts by weight: 20-50 parts of graphene, 10-50 parts of sodium silicate, 10-20 parts of aluminum powder, 5-18 parts of kaolin, 5-30 parts of monocalcium phosphate and 18-35 parts of boron trioxide;

the liquid consists of the following components in parts by weight: 1-10 parts of water-soluble phenolic resin, 0.1-1.5 parts of organic silicon coupling agent and 50-100 parts of water.

Wherein, the kaolin can be common kaolin or modified kaolin sold in the market.

Wherein the water-soluble phenolic resin is water-soluble phenolic resin, and the raw material can be directly purchased from the market. The water-soluble phenolic resin functions as a binder and a dispersant.

The organic silicon coupling agent is at least one of methyl trichlorosilane, dimethyl dichlorosilane, phenyl trichlorosilane, diphenyl dichlorosilane or methyl phenyl dichlorosilane.

In one embodiment, the fineness of the graphene is more than 1200 meshes, the fineness of the sodium silicate is more than 80 meshes, the fineness of the aluminum powder is more than 200 meshes, the fineness of the kaolin is more than 320 meshes, the fineness of the monocalcium phosphate is more than 320 meshes, and the fineness of the diboron trioxide is more than 70 meshes.

In one embodiment, the aluminum content of the aluminum powder is greater than or equal to 99.5%.

In one embodiment, the coating consists of a solid powder and a liquid;

the solid powder consists of the following components in parts by weight: 28-40 parts of graphene, 17-35 parts of sodium silicate, 10-15 parts of aluminum powder, 5-10 parts of kaolin, 12-20 parts of monocalcium phosphate and 20-25 parts of boron trioxide; the liquid consists of the following components in parts by weight: 1.5-2.5 parts of water-soluble phenolic resin, 0.1-0.2 part of organic silicon coupling agent and 60-65 parts of water.

In one embodiment, the solid powder consists of the following components in parts by weight: 30-40 parts of graphene, 20-35 parts of sodium silicate, 12-15 parts of aluminum powder, 5-10 parts of kaolin, 12-20 parts of monocalcium phosphate and 20-21 parts of boron trioxide; the liquid consists of the following components in parts by weight: 2-2.2 parts of water-soluble phenolic resin, 0.1-0.2 part of organic silicon coupling agent and 60-65 parts of water.

In one embodiment, the solid powder consists of the following components in parts by weight: 30-40 parts of graphene, 20-35 parts of sodium silicate, 15 parts of aluminum powder, 10 parts of kaolin, 12-20 parts of monocalcium phosphate and 20-21 parts of boron trioxide.

In one embodiment, the solid powder consists of the following components in parts by weight: 40 parts of graphene, 35 parts of sodium silicate, 15 parts of aluminum powder, 10 parts of kaolin, 20 parts of monocalcium phosphate and 21 parts of boron trioxide; the liquid consists of the following components in parts by weight: 2 parts of water-soluble phenolic resin, 0.1 part of organic silicon coupling agent and 60 parts of water.

The invention solves the second technical problem by providing a preparation method of the heat treatment coating for the nuclear power heavy forging.

The preparation method of the nuclear power heavy forging heat treatment coating comprises the following steps: and (3) uniformly dispersing the solid powder and the liquid, and sanding for at least 60min after dispersion is finished to obtain the product.

In one embodiment, the viscosity of the coating is 130 to 140Be ° at room temperature.

The invention also provides a use method of the nuclear power heavy forging heat treatment coating.

The application method of the nuclear power heavy forging heat treatment coating comprises the step of directly spraying the nuclear power heavy forging heat treatment coating on the surface of a forging, wherein the coating thickness is more than or equal to 0.5 mm.

The invention has the beneficial effects that:

1. the invention provides an antioxidant coating for a nuclear power heavy forging in the heat treatment and forging heating processes, which is simple in use method, can be directly applied to the surface of a forging by a spraying or brushing method, and solves the problems of low construction speed caused by large surface area of the forging, difficulty in construction caused by high temperature on the surface of the forging and the like.

2. The coating disclosed by the invention is excellent in oxidation resistance effect, convenient in oxidation resistance protection when the nuclear power forging is forged and heated for multiple times at the temperature of 1200 ℃ or above, high in coating speed on the surface of the forging, convenient to use, easy to form a film, free of temperature limitation, and capable of reducing the oxidation weight gain caused by a long-time (more than 30 hours) heating process by more than 95%.

Detailed Description

The nuclear power heavy forging heat treatment coating comprises solid powder and liquid; the solid powder consists of the following components in parts by weight: 20-50 parts of graphene, 10-50 parts of sodium silicate, 10-20 parts of aluminum powder, 5-18 parts of kaolin, 5-30 parts of monocalcium phosphate and 18-35 parts of boron trioxide; the liquid consists of the following components in parts by weight: 1-10 parts of water-soluble phenolic resin, 0.1-1.5 parts of organic silicon coupling agent and 50-100 parts of water.

Wherein, the kaolin can be common kaolin or modified kaolin sold in the market.

Wherein the water-soluble phenolic resin is water-soluble phenolic resin; the raw material can be purchased directly from the market. The water-soluble phenolic resin is used as a binder and a dispersant.

The organic silicon coupling agent is at least one of methyl trichlorosilane, dimethyl dichlorosilane, phenyl trichlorosilane, diphenyl dichlorosilane or methyl phenyl dichlorosilane.

In one embodiment, the fineness of the graphene is more than 1200 meshes, the fineness of the sodium silicate is more than 80 meshes, the fineness of the aluminum powder is more than 200 meshes, the fineness of the kaolin is more than 320 meshes, the fineness of the monocalcium phosphate is more than 320 meshes, and the fineness of the diboron trioxide is more than 70 meshes.

In one embodiment, the aluminum content of the aluminum powder is greater than or equal to 99.5%.

In one embodiment, the coating consists of a solid powder and a liquid;

the solid powder consists of the following components in parts by weight: 28-40 parts of graphene, 17-35 parts of sodium silicate, 10-15 parts of aluminum powder, 5-10 parts of kaolin, 12-20 parts of monocalcium phosphate and 20-25 parts of boron trioxide; the liquid consists of the following components in parts by weight: 1.5-2.5 parts of water-soluble phenolic resin, 0.1-0.2 part of organic silicon coupling agent and 60-65 parts of water.

In one embodiment, the solid powder consists of the following components in parts by weight: 30-40 parts of graphene, 20-35 parts of sodium silicate, 12-15 parts of aluminum powder, 5-10 parts of kaolin, 12-20 parts of monocalcium phosphate and 20-21 parts of boron trioxide; the liquid consists of the following components in parts by weight: 2-2.2 parts of water-soluble phenolic resin, 0.1-0.2 part of organic silicon coupling agent and 60-65 parts of water.

In one embodiment, the solid powder consists of the following components in parts by weight: 30-40 parts of graphene, 20-35 parts of sodium silicate, 15 parts of aluminum powder, 10 parts of kaolin, 12-20 parts of monocalcium phosphate and 20-21 parts of boron trioxide.

In one embodiment, the solid powder consists of the following components in parts by weight: 40 parts of graphene, 35 parts of sodium silicate, 15 parts of aluminum powder, 10 parts of kaolin, 20 parts of monocalcium phosphate and 21 parts of boron trioxide; the liquid consists of the following components in parts by weight: 2 parts of water-soluble phenolic resin, 0.1 part of organic silicon coupling agent and 60 parts of water.

The preparation method of the nuclear power heavy forging heat treatment coating comprises the following steps: and (3) uniformly dispersing the solid powder and the liquid, and sanding for at least 60min after dispersion is finished to obtain the product.

One specific preparation method is as follows: adding the solid powder and the liquid into a high-speed dispersion machine in batches according to the specified proportion, uniformly stirring at the speed of 100 plus materials at 200r/min, adjusting the distance between a dispersion disc and the bottom of a charging barrel to enable vortex to be in a shallow basin shape, increasing the rotating speed after all the raw materials are added, stirring at the speed of 700 plus materials at 1500 r/min for 60min, and using a jacket for water cooling to prevent the temperature from rising too high during dispersion. After dispersion is finished, transferring the mixture into a sand mill for sanding for 60 minutes, and adjusting the viscosity of the coating to Be 130-140 DEG Be by using the residual distilled water at room temperature to obtain the coating for the heating process of forging the nuclear power heavy forging.

In one embodiment, the viscosity of the coating is 130 to 140Be ° at room temperature.

The invention also provides a use method of the nuclear power heavy forging heat treatment coating.

The application method of the nuclear power heavy forging heat treatment coating comprises the step of directly spraying the nuclear power heavy forging heat treatment coating on the surface of a forging, wherein the coating thickness is more than or equal to 0.5 mm.

In one embodiment, the device for spraying may be a compressed air spraying device or a high pressure airless spraying device.

In one embodiment, the coating can be sprayed directly onto the high temperature surface of the forging if the forging is being forged during heating.

The forging is placed in a heat treatment furnace or a forging heating furnace for heating, and the coating is automatically melted to form a film in the process, so that oxygen in the air in the furnace can not generate common oxidation reaction with the forging, and the purpose of oxidation resistance in the heating process is achieved. The surface of the forging piece does not need to be treated before spraying, so the use is very convenient and efficient.

The following examples are provided to further illustrate the embodiments of the present invention and are not intended to limit the scope of the present invention.

The organosilicon coupling agent used in the following examples and comparative examples was methyltrichlorosilane.

Example 1

Weighing 35 parts of graphene, 35 parts of sodium silicate, 12 parts of metal aluminum powder, 5 parts of kaolin, 15 parts of monocalcium phosphate, 20 parts of boron trioxide, 2 parts of water-soluble phenolic resin, 0.1 part of organosilicon coupling agent and 60 parts of distilled water; the above are all parts by weight; wherein the fineness of the graphene is more than 1200 meshes, the fineness of the sodium silicate powder is more than 80 meshes, the fineness of the metal aluminum powder is more than 200 meshes, the fineness of the kaolin is more than 320 meshes, the fineness of the monocalcium phosphate is more than 320 meshes, and the fineness of the diboron trioxide is more than 70 meshes; the aluminum content in the metal aluminum powder is more than or equal to 99.5 percent.

The preparation process comprises the following steps: adding the solid powder and the liquid into a high-speed dispersion machine in batches according to the specified proportion, uniformly stirring at the speed of 200r/min, adjusting the distance between a dispersion disc and the bottom of a charging barrel to enable the vortex to be shallow basin-shaped, increasing the rotating speed after all the raw materials are added, stirring at the speed of 1000 r/min for 60 minutes, and cooling by introducing water through a jacket to prevent the temperature from rising too high during dispersion. After dispersion is finished, transferring the mixture into a sand mill for sanding for 60 minutes, and adjusting the viscosity of the coating to Be 130-140 DEG Be by using the residual distilled water at room temperature to obtain the coating for the heating process of forging the nuclear power heavy forging.

The coating process comprises the following steps: the coating is coated on a carbon steel workpiece 20NiMnMo, and the thickness is not less than 0.50 mm.

Heating conditions: the heating temperature, the heat preservation time and the use effect are shown in the table 1.

Example 2

Weighing 40 parts of graphene, 35 parts of sodium silicate, 15 parts of metal aluminum powder, 10 parts of kaolin, 20 parts of monocalcium phosphate, 21 parts of boron trioxide, 2 parts of water-soluble phenolic resin, 0.1 part of organosilicon coupling agent and 60 parts of distilled water; the above are all parts by weight; wherein the fineness of the graphene is more than 1200 meshes, the fineness of the sodium silicate powder is more than 80 meshes, the fineness of the metal aluminum powder is more than 200 meshes, the fineness of the kaolin is more than 320 meshes, the fineness of the monocalcium phosphate is more than 320 meshes, and the fineness of the diboron trioxide is more than 70 meshes; the aluminum content in the metal aluminum powder is more than or equal to 99.5 percent.

The preparation process is the same as that of example 1; the workpiece to be coated is a carbon steel workpiece 20 NiMnMo; the coating process was identical to example 1; heating conditions: the heating temperature, the heat preservation time and the use effect are shown in the table 1.

Example 3

Weighing 28 parts of graphene, 17 parts of sodium silicate, 10 parts of metal aluminum powder, 10 parts of kaolin, 12 parts of monocalcium phosphate, 25 parts of boron trioxide, 1.5 parts of water-soluble phenolic resin, 0.2 part of organic silicon coupling agent and 60 parts of distilled water; the above are all parts by weight; wherein the fineness of the graphene is more than 1200 meshes, the fineness of the sodium silicate powder is more than 80 meshes, the fineness of the metal aluminum powder is more than 200 meshes, the fineness of the kaolin is more than 320 meshes, the fineness of the monocalcium phosphate is more than 320 meshes, and the fineness of the diboron trioxide is more than 70 meshes; the aluminum content in the metal aluminum powder is more than or equal to 99.5 percent.

The preparation process is the same as that of example 1; the workpiece to be coated is a carbon steel workpiece 20 NiMnMo; the coating process was identical to example 1; heating conditions: the heating temperature, the heat preservation time and the use effect are shown in the table 1.

Example 4

Weighing 30 parts of graphene, 20 parts of sodium silicate, 15 parts of metal aluminum powder, 10 parts of kaolin, 12 parts of monocalcium phosphate, 20 parts of boron trioxide, 2.2 parts of water-soluble phenolic resin, 0.2 part of organic silicon coupling agent and 65 parts of distilled water; the above are all parts by weight; wherein the fineness of the graphene is more than 1200 meshes, the fineness of the sodium silicate powder is more than 80 meshes, the fineness of the metal aluminum powder is more than 200 meshes, the fineness of the kaolin is more than 320 meshes, the fineness of the monocalcium phosphate is more than 320 meshes, and the fineness of the diboron trioxide is more than 70 meshes; the aluminum content in the metal aluminum powder is more than or equal to 99.5 percent.

The preparation process is the same as that of example 1; the workpiece to be coated is a carbon steel workpiece 20 NiMnMo; the coating process was identical to example 1; heating conditions: the heating temperature, the heat preservation time and the use effect are shown in the table 1.

Comparative example 1

Weighing 30 parts of graphene, 20 parts of sodium silicate, 0 part of metal aluminum powder, 10 parts of kaolin, 12 parts of monocalcium phosphate, 20 parts of boron trioxide, 2.2 parts of water-soluble phenolic resin, 0.2 part of organic silicon coupling agent and 65 parts of distilled water; the above are all parts by weight; wherein the fineness of the graphene is more than 1200 meshes, the fineness of the sodium silicate powder is more than 80 meshes, the fineness of the kaolin is more than 320 meshes, the fineness of the monocalcium phosphate is more than 320 meshes, and the fineness of the boron trioxide is more than 70 meshes.

The preparation process is the same as that of example 4; the coating process and the carbon steel workpiece to be coated are completely consistent with the example 4; heating conditions: the heating temperature, the heat preservation time and the use effect are shown in the table 2.

Comparative example 2

Weighing 30 parts of graphene, 20 parts of sodium silicate, 15 parts of iron powder, 10 parts of kaolin, 12 parts of monocalcium phosphate, 20 parts of boron trioxide, 2.2 parts of water-soluble phenolic resin, 0.2 part of organic silicon coupling agent and 65 parts of distilled water; the above are all parts by weight; wherein the fineness of the graphene is more than 1200 meshes, the fineness of the sodium silicate is more than 80 meshes, the fineness of the iron powder is more than 200 meshes, the fineness of the kaolin is more than 320 meshes, the fineness of the monocalcium phosphate is more than 320 meshes, and the fineness of the boron trioxide is more than 70 meshes; the iron content in the iron powder is more than or equal to 99.5 percent.

The preparation process is the same as that of example 4; the coating process and the carbon steel workpiece to be coated are completely consistent with the example 4; heating conditions: the heating temperature, the heat preservation time and the use effect are shown in the table 2.

Comparative example 3

Weighing 30 parts of graphene, 20 parts of sodium silicate, 15 parts of metal aluminum powder, 10 parts of kaolin, 12 parts of mica powder, 20 parts of boron trioxide, 2.2 parts of water-soluble phenolic resin, 0.2 part of organic silicon coupling agent and 65 parts of distilled water; the above are all parts by weight; wherein the fineness of the graphene is more than 1200 meshes, the fineness of the sodium silicate is more than 80 meshes, the fineness of the metal aluminum powder is more than 200 meshes, the fineness of the kaolin is more than 320 meshes, the fineness of the mica powder is more than 320 meshes, the fineness of the boron trioxide is more than 70 meshes, and the aluminum content in the metal aluminum powder is more than or equal to 99.5%.

The preparation process is the same as that of example 4; the coating process and the carbon steel workpiece to be coated are completely consistent with the example 4; heating conditions: the heating temperature, the heat preservation time and the use effect are shown in the table 2.

Comparative example 4

Weighing 45 parts of colloidal graphite powder, 35 parts of sodium silicate, 10 parts of metal aluminum powder, 12 parts of iron powder, 5 parts of kaolin, 15 parts of mica powder, 22 parts of boron trioxide, 2.2 parts of water-soluble phenolic resin, 0.2 part of organic silicon coupling agent and 65 parts of distilled water; the above are all parts by weight; wherein the fineness of the graphene is more than 1200 meshes, the fineness of the sodium silicate is more than 80 meshes, the fineness of the metal aluminum powder is more than 200 meshes, the fineness of the iron powder is more than 200 meshes, the fineness of the kaolin is more than 320 meshes, the fineness of the mica powder is more than 320 meshes, the fineness of the boron trioxide is more than 70 meshes, the aluminum content in the metal aluminum powder is more than or equal to 99.5 percent, and the iron content in the iron powder is more than or equal to 99.5 percent.

The preparation process is the same as that of example 4; the coating process and the carbon steel workpiece to be coated are completely consistent with the example 4; heating conditions: the heating temperature, the heat preservation time and the use effect are shown in the table 2.

Table 1: powder composition and use effect of each example

Table 2: various proportional powder compositions and use effect

Oxidation weight gain reduction rate (oxidation weight gain without protective coating-oxidation weight gain after protective coating application)/oxidation weight gain without protective coating application

The oxidation weight gain ratio (weight before heating-weight after heating)/weight before heating.