阅读说明：本技术 宽温域自润滑VN-Ag2MoO4复合材料及其制备方法 (Wide-temperature-range self-lubricating VN-Ag2MoO4Composite material and preparation method thereof ) 是由 刘二勇 杜双明 陈树 于 2020-06-23 设计创作，主要内容包括：本发明一种宽温域自润滑VN-Ag<Sub>2</Sub>MoO<Sub>4</Sub>复合材料及其制备方法。以克服现有技术存在的在高温、宽温域的苛刻工况下服役时现有自润滑复合材料无法达到使用要求的问题。本发明一种宽温域自润滑VN-Ag<Sub>2</Sub>MoO<Sub>4</Sub>复合材料,其质量组成为：85-95％的VN粉和5-15％的钼酸银粉；所述钼酸银粉为Ag<Sub>2</Sub>MoO<Sub>4</Sub>相结构粉末；宽温域自润滑VN-Ag<Sub>2</Sub>MoO<Sub>4</Sub>复合材料的制备方法为：1)将85-95％的VN粉和5-15％的Ag<Sub>2</Sub>MoO<Sub>4</Sub>粉末混合,湿式球磨,干燥、过筛,得混合粉料；2)将混合粉料放入石墨磨具中,进行冷压处理；3)将装有混合粉料的石墨磨具在真空保护下进行热压烧结,得到宽温域自润滑VN-Ag<Sub>2</Sub>MoO<Sub>4</Sub>复合材料。(The invention discloses wide-temperature-range self-lubricating VN-Ag 2 MoO 4 Composite materials and methods for making the same. The problem that the existing self-lubricating composite material cannot meet the use requirement when the existing self-lubricating composite material is in service under the harsh working conditions of high temperature and wide temperature range in the prior art is solved. The invention discloses wide-temperature-range self-lubricating VN-Ag 2 MoO 4 The composite material comprises the following components in percentage by mass: 85-95% of VN powder and 5-15% of silver molybdate powder; the silver molybdate powder is Ag 2 MoO 4 A phase structure powder; wide-temperature-range self-lubricating VN-Ag 2 MoO 4 The preparation method of the composite material comprises the following steps: 1) mixing 85-95% VN powder and 5-15% Ag 2 MoO 4 Mixing the powder, performing wet ball milling, drying and sieving to obtain mixed powder; 2) putting the mixed powder into a graphite grinding tool for coolingPressing; 3) carrying out hot-pressing sintering on the graphite grinding tool filled with the mixed powder under the vacuum protection to obtain the wide-temperature-range self-lubricating VN-Ag 2 MoO 4 A composite material.)

1. Wide-temperature-range self-lubricating VN-Ag₂MoO₄A composite material characterized by: the weight composition is as follows: 85-95% of VN powder and 5-15% of silver molybdate powder; the silver molybdate powder is Ag₂MoO₄A phase structure powder.

2. Wide-temperature-range self-lubricating VN-Ag₂MoO₄The preparation method of the composite material comprises the following steps:

1) mixing 85-95% VN powder and 5-15% Ag₂MoO₄Mixing the powder, performing wet ball milling, drying and sieving to obtain mixed powder;

2) putting the mixed powder into a graphite grinding tool, and carrying out cold pressing treatment;

3) carrying out hot-pressing sintering on the graphite grinding tool filled with the mixed powder under the vacuum protection to obtain the wide-temperature-range self-lubricating VN-Ag₂MoO₄A composite material.

3. Wide temperature range self-lubricating VN-Ag of claim 2₂MoO₄The preparation method of the composite material is characterized by comprising the following steps: the ball-material ratio in the ball milling process in the step 2) is 3: 1-5: 1, the ball milling rotation speed is 100-300 r/min, and the ball milling time is 5-15 hours.

4. Wide temperature range self-lubricating VN-Ag of claim 3₂MoO₄The preparation method of the composite material is characterized by comprising the following steps: in the step 3), the sintering temperature is 1500-1700 ℃, the heating rate is 2-10 ℃/min, the sintering pressure is 10-30 MPa, and the heat preservation time is 0.5-1.5 h.

Technical Field

The invention relates to the technical field of ceramic-based self-lubricating composite materials, in particular to wide-temperature-range self-lubricating VN-Ag₂MoO₄Composite materials and methods for making the same.

Background

With the continuous development of high and new technology industries such as aerospace, nuclear power and the like, more and more friction pair parts need to be in service under the harsh working conditions of high temperature and wide temperature range, and the lubricating and wear-resisting properties of the corresponding materials of the parts in the high temperature and wide temperature range are widely concerned and researched. Therefore, the lubrication and wear resistance of the above components in a wide temperature range environment becomes a key factor affecting the reliability and life of the whole system, and increasingly higher requirements are put on the lubrication performance of the materials. The high strength, high hardness, good oxidation resistance and high temperature chemical stability of high performance structural ceramics, which can provide good load bearing capacity as a matrix of composite materials. Generally, a ceramic-based self-lubricating composite material is prepared by adding a proper solid lubricant into ceramic, or a new lubricating substance is generated under the action of temperature, pressure and the like to improve the lubricity of the ceramic-based self-lubricating composite material, so that the preparation of the ceramic-based self-lubricating composite material is completed, and the ceramic-based self-lubricating composite material has both high strength and continuous lubricating performance.

The lubricants commonly used for self-lubricating composite materials include several systems:

one is represented by Pb, Ag, etc., but the high temperature and high pressure of the preparation process causes the overflow of low melting point metal, thereby being weak or losing lubrication;

another MoS represented by a layered solid lubricant₂And graphite is easy to oxidize and lose efficacy at the temperature higher than 400 ℃, so that the graphite cannot be applied to high-temperature working conditions;

also some metal oxides (e.g. MoO)₃、CuO、V₂O₅TaO and Re₂O₇Etc.) has lower shearing strength at higher temperature, and plays a good role in high-temperature lubrication. However, under medium and low temperature conditions, oxide lubricants are generally prone to forming brittle wear debris during the friction process, which ultimately affects the wide temperature range lubrication performance of the composite material.

Disclosure of Invention

The invention aims to provide wide-temperature-range self-lubricating VN-Ag₂MoO₄Composite material and preparation method thereof, aiming at overcoming the defects of high temperature and wide temperature in the prior artThe problem that the prior self-lubricating composite material can not meet the use requirement when in service under the harsh working condition of the domain.

In order to achieve the purpose, the invention provides the following technical scheme:

wide-temperature-range self-lubricating VN-Ag₂MoO₄The composite material comprises the following components in percentage by mass: 85-95% of VN powder and 5-15% of silver molybdate powder; the silver molybdate powder is Ag₂MoO₄A phase structure powder.

Wide-temperature-range self-lubricating VN-Ag₂MoO₄The preparation method of the composite material comprises the following steps:

1) mixing 85-95% VN powder and 5-15% Ag₂MoO₄Mixing the powder, performing wet ball milling, drying and sieving to obtain mixed powder;

2) putting the mixed powder into a graphite grinding tool, and carrying out cold pressing treatment;

3) carrying out hot-pressing sintering on the graphite grinding tool filled with the mixed powder under the vacuum protection to obtain the wide-temperature-range self-lubricating VN-Ag₂MoO₄A composite material.

As a further improvement of the preparation method, the ball-material ratio in the ball milling process in the step 2) is 3: 1-5: 1, the ball milling rotation speed is 100-300 r/min, and the ball milling time is 5-15 hours.

As a further improvement of the preparation method, in the step 3), the sintering temperature is 1500-1700 ℃, the heating rate is 2-10 ℃/min, the sintering pressure is 10-30 MPa, and the heat preservation time is 0.5-1.5 h.

Compared with the prior art, the invention has the following advantages:

1) the invention selects silver molybdate and vanadium nitride to form the self-lubricating composite material, wherein Ag is₂MoO₄The lubricating phase is decomposed to form a soft metal Ag lubricating phase in the vacuum sintering process, the soft metal Ag lubricating phase is tightly combined with a matrix, the loss and agglomeration of the lubricating phase in the simple substance Ag adding process are improved, and the medium-low temperature lubricating property comes from Ag₂MoO₄The soft metal Ag generated by decomposition has VN-Ag in the high-temperature friction process due to the high-temperature lubrication effect₂MoO₄The composite material regenerates the silver molybdate and silver vanadate lubricant through a tribochemical reaction.

2) The high-temperature self-lubricating composite material prepared by the invention has a uniform tissue structure, the lubricating phase and the matrix are tightly combined, the loss of the lubricating phase in the sintering process of adding metal Ag is solved, and the high-temperature self-lubricating composite material has excellent self-lubricating effect and wear resistance in the temperature range from room temperature to 700 ℃.

3) Wide-temperature-range self-lubricating VN-Ag prepared by adopting method₂MoO₄The composite material effectively improves the friction and wear performance of the VN ceramic in the range of RT-700 ℃, for example, the wear rates of RT, 300 ℃, 500 ℃ and 700 ℃ are respectively reduced by about 71%, 70%, 73% and 72% compared with the VN ceramic.

4) The invention has wide temperature range and self-lubricating VN-Ag₂MoO₄Compared with the vapor deposition technology, the preparation process of the composite material has the advantages of mature process, less equipment investment, low cost and the like, and also has the advantages of easy acquisition of materials, low cost and easy yield amplification, so the wide-temperature-range self-lubricating VN-Ag material has the advantages of wide temperature range and wide application range₂MoO₄The composite material has the advantages of low cost, simple production process, suitability for large-scale production and the like.

5) The high-temperature self-compensation wear-resistant material and the design method can meet the requirements of lubrication and wear resistance under the condition of wide temperature range, are suitable for the fields of aerospace, metallurgy, automobiles and the like, and have wide application prospect as the processing material of high-temperature motion system components such as bearings, seals and the like.

Drawings

FIG. 1 shows that the ball milling and vacuum sintering are used to prepare wide temperature range self-lubricating VN-Ag in example 1 of the present invention₂MoO₄Composition diagram of composite material phase;

FIG. 2 shows the ball milling and vacuum sintering process of preparing wide temperature range self-lubricating VN-15 wt.% Ag in example 1 of the present invention₂MoO₄A composite material micro-topography map;

FIG. 3 shows a wide temperature range self-lubricating VN-15 wt.% Ag in example 1 of the present invention₂MoO₄Different temperature friction coefficient (a) and wear rate test pattern (b) of the composite material.

FIGS. 4 to 7 show wide temperature range self-lubricating VN-Ag obtained in example 1₂MoO₄The composite material is respectively stripped at room temperature, 300 ℃, 500 ℃ and 700 DEG CAnd (5) surface topography of grinding marks under the workpiece.

FIG. 8 shows a wide temperature range self-lubricating VN-15 wt.% Ag in example 1 of the present invention₂MoO₄Phase analysis result graphs of different temperature abrasion areas of the composite material.

Fig. 9 is a micro-topography of VN-15 wt.% Ag composites.

Detailed Description

In order to more clearly explain the technical solution of the present invention, the present invention will be described in detail by examples and drawings.

One aspect of the invention provides a wide temperature range self-lubricating VN-Ag₂MoO₄And (3) selecting a proper lubricant ratio and mechanically mixing with VN. Wherein the VN ceramic has excellent high-temperature mechanical property and wear resistance; by addition of Ag₂MoO₄The powder improves the lubricity of the material, wherein Ag₂MoO₄The soft metal Ag formed by decomposition in the sintering process provides medium and low temperature lubrication, and the silver molybdate and the silver vanadate generated in the high temperature friction process provide high temperature lubrication. The Ag is₂MoO₄The lubricating phase is decomposed to form a soft metal Ag lubricating phase in the vacuum sintering process, and the soft metal Ag lubricating phase is tightly combined with a matrix, so that the loss and agglomeration of the lubricating phase in the process of adding simple substance Ag are improved.

Another aspect of the invention provides wide temperature range self-lubricating VN-Ag₂MoO₄Preparation method of composite material, VN powder and Ag are carried out by ball milling technology₂MoO₄Mixing the powder to obtain uniform mixed powder; and putting the mixed powder into a graphite grinding tool, and preparing by adopting a hot-pressing sintering technology under vacuum protection to obtain the wide-temperature-range continuous self-lubricating composite material.

Wide-temperature-range self-lubricating VN-Ag₂MoO₄The composite material comprises the following components in percentage by mass: the mixed powder comprises the following raw materials in percentage by weight: 85-95% of VN powder and 5-15% of silver molybdate powder;

as a further improvement, the silver molybdate powder is Ag₂MoO₄A phase structure powder;

a preparation method of a wide temperature range nickel-based self-lubricating composite material comprises the following steps:

1) weighing 85-95% of VN powder and 5-15% of Ag according to weight ratio₂MoO₄Powder to obtain the original ingredients;

2) performing mechanical alloying on the original ingredients by using a planetary ball mill to obtain uniform mixed powder;

3) and putting the mixed powder into a graphite grinding tool, and preparing by adopting a hot-pressing sintering technology under vacuum protection to obtain the wide-temperature-range continuous self-lubricating composite material.

The VN powder is purchased from the market, and the average particle size is 15 mu m; the Ag is₂MoO₄The powder is prepared by chemical synthesis or purchased from market, and has an average particle size of 10 μm.

As a further improvement of the preparation method, the ball-material ratio in the ball milling process in the step 2) is 3: 1-5: 1, the ball milling rotation speed is 100-300 r/min, and the ball milling time is 5-15 h.

As a further improvement of the preparation method, in the step 3), the sintering temperature is 1500-1700 ℃, the heating rate is 2-10 ℃/min, the sintering pressure is 10-30 MPa, and the heat preservation time is 0.5-1.5 h.

The invention is further illustrated by the following examples: the invention will be better understood from the following examples. However, those skilled in the art will readily appreciate that the specific material ratios, process conditions and results thereof described in the examples are illustrative only and should not be taken as limiting the invention as detailed in the claims.