阅读说明：本技术 一种润滑油用石墨烯-陶瓷微球抗磨添加剂及制备方法 (Graphene-ceramic microsphere anti-wear additive for lubricating oil and preparation method thereof ) 是由 陈庆 曾军堂 张俊 陈涛 于 2020-04-17 设计创作，主要内容包括：本发明涉及润滑油添加剂领域,公开了一种润滑油用石墨烯-陶瓷微球抗磨添加剂及制备方法。包括如下制备过程：(1)将纳米陶瓷微球、氧化石墨烯、分散剂加入氢氧化铝胶体分散均匀,利用均质机分散,制得分散液；(2)将分散液喷雾干燥,得到预处理微粒；(3)将预处理微粒置于水合肼液中超声振荡处理,过滤、烘干,得到复合物微球；(4)将复合微球与脂肪酸混合研磨,即得润滑油用石墨烯-陶瓷微球抗磨添加剂。本发明制得的抗磨添加剂用于润滑油,一方面产生良好的微轴承滚动效应,摩擦系数低；另一方面纳米陶瓷微球的包覆层石墨烯微片在高载荷使会被部分研磨剥层脱离出单片石墨烯,能够快速修复磨损的微缺陷,提升润滑油的抗磨性。(The invention relates to the field of lubricating oil additives, and discloses a graphene-ceramic microsphere anti-wear additive for lubricating oil and a preparation method thereof. The preparation method comprises the following preparation processes: (1) adding the nano ceramic microspheres, the graphene oxide and the dispersing agent into aluminum hydroxide colloid for uniform dispersion, and dispersing by using a homogenizer to prepare a dispersion solution; (2) spray-drying the dispersion to obtain pretreated particles; (3) placing the pretreated particles in hydrazine hydrate liquid for ultrasonic oscillation treatment, filtering and drying to obtain composite microspheres; (4) and mixing and grinding the composite microspheres and fatty acid to obtain the graphene-ceramic microsphere anti-wear additive for the lubricating oil. The anti-wear additive prepared by the invention is used for lubricating oil, on one hand, the anti-wear additive generates good micro-bearing rolling effect, and the friction coefficient is low; on the other hand, the graphene microchip of the coating layer of the nano ceramic microsphere can be partially ground and delaminated to separate out single graphene under high load, so that the worn micro-defect can be quickly repaired, and the wear resistance of the lubricating oil is improved.)

1. A preparation method of a graphene-ceramic microsphere anti-wear additive for lubricating oil is characterized by comprising the following specific steps:

(1) firstly, adding the nano ceramic microspheres, the graphene oxide and the dispersing agent into aluminum hydroxide colloid for uniform dispersion, fully coating the ceramic microspheres with the graphene oxide and aluminum hydroxide colloid, and then dispersing by using a homogenizer to prepare a dispersion solution; the raw materials comprise, by weight, 15-25 parts of nano ceramic microspheres, 1-3 parts of graphene oxide, 0.1-0.5 part of dispersing agent and 80-100 parts of aluminum hydroxide colloid;

(2) firstly, spray-drying the dispersion liquid prepared in the step (1) by high pressure and heating, and then collecting to obtain pretreated particles;

(3) placing the pretreated particles obtained in the step (2) in hydrazine hydrate solution, carrying out ultrasonic oscillation treatment, then refluxing, filtering and drying to obtain the composite microspheres of graphene microchip coated nano ceramic microspheres;

(4) firstly, mixing the composite microspheres with fatty acid, then grinding the mixture by a sand mill, and collecting the mixture to obtain the graphene-ceramic microsphere anti-wear additive for lubricating oil; the raw materials comprise, by weight, 3-6 parts of composite microspheres and 1-2 parts of fatty acid.

2. The preparation method of the graphene-ceramic microsphere antiwear additive for lubricating oil according to claim 1, wherein the graphene-ceramic microsphere antiwear additive for lubricating oil is prepared by the following steps: the nano ceramic microspheres in the step (1) are one of Zr-N nano ceramic microspheres and Zn-N nano ceramic microspheres, and the particle size is 10-100 nm.

3. The preparation method of the graphene-ceramic microsphere antiwear additive for lubricating oil according to claim 1, wherein the graphene-ceramic microsphere antiwear additive for lubricating oil is prepared by the following steps: the dispersant in the step (1) is dialkyl dithiophosphate.

4. The preparation method of the graphene-ceramic microsphere antiwear additive for lubricating oil according to claim 1, wherein the graphene-ceramic microsphere antiwear additive for lubricating oil is prepared by the following steps: the mass concentration of the aluminum hydroxide colloid in the step (1) is 8-10%.

5. The preparation method of the graphene-ceramic microsphere anti-wear additive for the lubricating oil as claimed in claim 1, wherein the working pressure of the homogenizer in the step (1) is 1.5-3.0 MPa, and the flow rate is 300-500L/h.

6. The preparation method of the graphene-ceramic microsphere antiwear additive for lubricating oil according to claim 1, wherein the graphene-ceramic microsphere antiwear additive for lubricating oil is prepared by the following steps: the pressure of the spray drying in the step (2) is 1.0-2.0 MPa, and the heating temperature is 280-300 ℃.

7. The preparation method of the graphene-ceramic microsphere antiwear additive for lubricating oil according to claim 1, wherein the graphene-ceramic microsphere antiwear additive for lubricating oil is prepared by the following steps: and (3) the hydrazine hydrate solution in the step (3) is a hydrazine hydrate aqueous solution with 60-70% of hydrazine hydrate content.

8. The preparation method of the graphene-ceramic microsphere antiwear additive for lubricating oil according to claim 1, wherein the graphene-ceramic microsphere antiwear additive for lubricating oil is prepared by the following steps: the frequency of the ultrasonic oscillation treatment in the step (3) is 30-50 kHz, the temperature is 80-90 ℃, and the time is 1-2 h; the reflux time is 10-24 h.

9. The preparation method of the graphene-ceramic microsphere antiwear additive for lubricating oil according to claim 1, wherein the graphene-ceramic microsphere antiwear additive for lubricating oil is prepared by the following steps: and (4) selecting an SW15-1 horizontal sand mill as the sand mill in the step (4), wherein the grinding speed is 600-800 r/min, and the grinding time is 5-10 min.

10. The graphene-ceramic microsphere anti-wear additive for the lubricating oil prepared by the method of any one of claims 1 to 9.

Technical Field

The invention relates to the field of lubricating oil additives, and discloses a graphene-ceramic microsphere anti-wear additive for lubricating oil and a preparation method thereof.

Background

The lubricating grease is a lubricating oil which is separated from petroleum and synthesized by hydrogenation, sulfonation, solvent extraction separation method and the like, is mainly used for reducing friction between surfaces of moving parts, and has cooling and sealing functions on machinery and equipment. With the development demand of high-performance equipment, the requirements on precision lubrication such as industrial machinery lubrication, transmission lubrication and the like are higher and higher. The lubricating effect of the lubricating oil is difficult to meet the requirements of many application occasions by simply adopting the lubricating oil, so that the lubricating oil is usually added with an auxiliary agent to improve the lubricating property and the anti-wear property of the lubricating oil.

In the lubricating oil additive, various nano particles and inorganic matters with layered structures are used to improve the wear resistance of the lubricating oil. The nano copper is a common antiwear agent in lubricating oil, and can obviously reduce the abrasion loss. The copper is softer, so that the lubricating oil can resist wear and repair defects when being used for high load. However, the nano copper is aggregated after being added into the base lubricating oil due to poor dispersibility, and the friction coefficient is increased. Layered inorganic substances such as molybdenum disulfide and graphite are mature and applied to lubricating oil, and layered substances have a certain lubricating effect and have the function of repairing defects, but the particles are large, so that the layered inorganic substances are obviously insufficient in the aspect of high-bearing precision lubrication.

The skilled person would like to be able to create rolling lubrication in the lubricating oil similar to that of a micro-bearing. When the nano microspheres are applied to lubricating oil, and the particles are small enough and the sphericity is high, the nano microspheres are dispersed in the lubricating oil to form countless micro bearings, and the lubricating effect of the micro bearings is increased sharply. The nanometer spherical nickel powder prepared by summer, delayed autumn and the like has greatly reduced friction coefficient and abrasion loss after being used for base oil. However, since the hardness of nickel is insufficient, the nickel powder is crushed under a high load, and the friction coefficient is increased. How to keep the high sphericity particles under high load still with good sliding and antiwear properties without breakage is a hot spot for high performance lubricating oil research. For example, the high-hardness nano ceramic ball has higher hardness, can not be fractured and damaged by high load, and can reduce the friction coefficient. However, the hard high-hardness ceramic microspheres have different action mechanisms from soft metal copper, layered graphite and the like, cannot repair abrasion defects, and the micro-bearings formed in a microcosmic mode have different particle sizes, so that the micro-bearings have a weak uniform supporting effect on high load and are easy to crack under high load. Meanwhile, the graphene and the high-hardness ceramic microspheres are difficult to be effectively and tightly combined, so that the high-hardness ceramic microspheres can be directly contacted with grease and mechanical parts to cause abrasion due to the fact that the graphene cannot effectively coat the high-hardness ceramic microspheres under high load when the graphene is used for lubricating oil.

According to the above, in the graphene and nano hard ceramic microspheres used for the lubricating oil additive in the existing scheme, due to poor coating property of graphene and ceramic microspheres, graphene falls off, and the nano ceramic microspheres are hard microspheres, have uneven particle sizes, cannot uniformly support high load, are easy to fracture after long-time work, and cannot effectively repair abrasion defects.

Disclosure of Invention

When the graphene and nano ceramic microspheres applied at present are used as lubricating oil additives, the graphene falls off due to poor coating performance of the graphene and the ceramic microspheres, so that the hard ceramic balls directly contact with mechanical parts to cause the problem of abrasion, and meanwhile, the nano ceramic microspheres cannot effectively repair abrasion defects.

The invention achieves the above purpose by the following technical scheme:

a preparation method of a graphene-ceramic microsphere anti-wear additive for lubricating oil comprises the following specific steps:

(1) firstly, adding the nano ceramic microspheres, the graphene oxide and the dispersing agent into aluminum hydroxide colloid for uniform dispersion, fully coating the ceramic microspheres with the graphene oxide and aluminum hydroxide colloid, and then dispersing by using a homogenizer to prepare a dispersion solution; the raw materials comprise, by weight, 15-25 parts of nano ceramic microspheres, 1-3 parts of graphene oxide, 0.1-0.5 part of dispersing agent and 80-100 parts of aluminum hydroxide colloid;

(2) firstly, spray-drying the dispersion liquid prepared in the step (1) by high pressure and heating, and then collecting to obtain pretreated particles;

(3) placing the pretreated particles obtained in the step (2) in hydrazine hydrate solution, carrying out ultrasonic oscillation treatment, then refluxing, filtering and drying to obtain the composite microspheres of graphene microchip coated nano ceramic microspheres;

(4) firstly, mixing the composite microspheres with fatty acid, then grinding the mixture by a sand mill, and collecting the mixture to obtain the graphene-ceramic microsphere anti-wear additive for lubricating oil; the raw materials comprise, by weight, 3-6 parts of composite microspheres and 1-2 parts of fatty acid.

The nano ceramic microspheres are high-strength, inert, hard and perfectly spherical superfine ceramic powder, can improve the fluidity and strength, increase the wear resistance and corrosion resistance, improve the appearance and stability and the like, and are different from irregularly-shaped particles, the nano ceramic microspheres can roll between each other easily, so that a system using the nano ceramic microspheres reduces the viscosity and the internal stress, has better fluidity, good leveling property and smooth surface, can ensure that lubricating oil can form the rolling effect of a micro bearing when being used as a lubricating oil additive, and has excellent lubricating effect. However, since the nano ceramic microspheres are hard microspheres, have uneven particle sizes, cannot uniformly support high loads, and are easily fractured after long-time work, and in addition, the nano ceramic microspheres cannot effectively repair wear defects, the nano ceramic microspheres need to be subjected to surface modification, and graphene is used for coating modification, so that the stability of the nano ceramic microspheres can be effectively improved, the capability of rapidly repairing wear micro defects is provided, the wear resistance and durability of lubricating oil are effectively promoted, and the wear-resistant additive for the lubricating oil is obtained. Preferably, the nano ceramic microspheres in the step (1) are one of Zr-N nano ceramic microspheres and Zn-N nano ceramic microspheres, and the particle size is 10-100 nm.

As a preferable mode of the present invention, the dispersant in the step (1) is a dialkyldithiophosphoric acid.

The aluminum hydroxide colloid has strong adhesion and good adsorption performance, and the graphene oxide microchip is adhered to the surface of the nano ceramic microsphere by utilizing the aluminum hydroxide colloid, so that the graphene oxide microchip is conveniently reduced into graphene in the subsequent process and firmly coats the nano ceramic microsphere. In the present invention, the aluminum hydroxide colloid in the step (1) preferably has a mass concentration of 8 to 10%.

Preferably, the working pressure of the homogenizer in the step (1) is 1.5-3.0 MPa, and the flow rate is 300-500L/h.

Through high-pressure spray drying, the nano ceramic microspheres with the surfaces adhered with the graphene oxide and the aluminum hydroxide colloid are dispersed, and the aluminum hydroxide is changed into aluminum oxide in situ through heating, so that the graphene oxide is firmly adhered to the surfaces of the ceramic microspheres. In the present invention, the pressure of the spray drying in the step (2) is preferably 1.0 to 2.0MPa, and the heating temperature is preferably 280 to 300 ℃.

The hydrazine hydrate is utilized to reduce the graphene oxide into the graphene microchip, and the obtained graphene microchip is coated on the surface of the nano ceramic microsphere, so that the coating effect of the graphene and the ceramic microsphere is better ensured. Preferably, the hydrazine hydrate solution in the step (3) is a hydrazine hydrate aqueous solution with 60-70% of hydrazine hydrate content.

Preferably, the frequency of the ultrasonic oscillation treatment in the step (3) is 30-50 kHz, the temperature is 80-90 ℃, and the time is 1-2 h.

Preferably, the reflux time in the step (3) is 10-24 h.

The fatty acid is added to perform sanding grinding on the nano ceramic coated with the graphene, and the graphene nanoplatelets are multi-layer graphene, so that the coating layers of the graphene nanoplatelets are partially ground and peeled off through sanding, the particle size of the composite microspheres is more uniform, the particle size uniformity is good when the composite microspheres are used for lubricating oil, and the rolling supporting effect is good; by grinding with fatty acid, the prepared antiwear additive is easy to disperse and use in the base lubricating oil, and is greatly convenient to add and use. Preferably, the sand mill in the step (4) is an SW15-1 horizontal sand mill, the grinding speed is 600-800 r/min, and the grinding time is 5-10 min.

When the graphene-ceramic microsphere anti-wear additive for the lubricating oil prepared by the method is used for the lubricating oil, the friction coefficient of the lubricating oil can be effectively reduced, and the anti-wear property of the lubricating oil can be remarkably improved. Through tests, when the prepared anti-wear additive is used for basic lubricating oil, the PB of the anti-wear performance test is 670-680N, PD which is 1884-1886N, and the diameter of a wear scar is 0.35-0.44 mm.

The invention provides a graphene-ceramic microsphere anti-wear additive for lubricating oil and a preparation method thereof, wherein nano ceramic microspheres, graphene oxide and dispersant dialkyl dithiophosphate are placed in aluminum hydroxide colloid to be uniformly dispersed, so that the graphene oxide and aluminum hydroxide colloid fully coat the ceramic microspheres, and are dispersed by a homogenizer to obtain a dispersion solution; carrying out high-pressure, heating and spray drying on the dispersion liquid to change aluminum hydroxide into aluminum oxide in situ, and bonding graphene oxide on the surface of the ceramic microsphere to obtain pretreated particles; placing the pretreated particles in hydrazine hydrate solution, carrying out ultrasonic oscillation treatment, filtering and drying to obtain the composite microspheres of graphene microchip coated nano ceramic microspheres; mixing the composite microspheres with fatty acid, and grinding by a sand mill.

The invention provides a graphene-ceramic microsphere anti-wear additive for lubricating oil and a preparation method thereof, compared with the prior art, the graphene-ceramic microsphere anti-wear additive has the outstanding characteristics and excellent effects that:

1. provides a method for preparing the graphene-ceramic microsphere anti-wear additive for the lubricating oil by firmly coating the nano ceramic microspheres with the graphene.

2. Graphene oxide is bonded on the surface of the nano ceramic microsphere through aluminum hydroxide colloid, then the aluminum hydroxide is changed into aluminum oxide in situ, the graphene oxide is reduced into graphene, and finally sanding treatment is carried out to obtain the nano ceramic microsphere with the surface firmly coated with graphene.

3. The anti-wear additive prepared by the invention is used for lubricating oil, on one hand, the anti-wear additive generates good micro-bearing rolling effect, and the friction coefficient is low; on the other hand, the graphene microchip of the coating layer of the nano ceramic microsphere can be partially ground and delaminated to separate out single graphene under high load, so that the worn micro-defect can be quickly repaired, and the wear resistance of the lubricating oil is improved.

Drawings

FIG. 1 is a schematic view of a graphene-ceramic microsphere anti-wear additive prepared according to the present invention; wherein: 1-ceramic microspheres; 2-graphene coating; 3-alumina adhesive layer.

Detailed Description

The present invention will be described in further detail with reference to specific embodiments, but it should not be construed that the scope of the present invention is limited to the following examples. Various substitutions and alterations can be made by those skilled in the art and by conventional means without departing from the spirit of the method of the invention described above.