CN114933771A - A kind of high temperature wear-resistant material and its preparation method and application - Google Patents

Abstract

The invention discloses a high-temperature wear-resistant material and a preparation method and application thereof, wherein the high-temperature wear-resistant material comprises the following components in parts by weight: 5-10 parts of polyimide, 2-5 parts of carbon fiber and 85-93 parts of polytetrafluoroethylene powder. The interface action among the three composite materials is beneficial to stress transfer and dispersion in the high-temperature friction and wear process, the polytetrafluoroethylene has proper resilience, good sealing is realized, the metal surface cannot be damaged in the grinding process of the polytetrafluoroethylene and a metal piece, the characteristics are beneficial to the durability and effectiveness of relevant parts, and the excellent wear-resistant sealing performance is realized in a high-temperature state.

Description

A kind of high temperature wear-resistant material and its preparation method and application

technical field

The invention belongs to the technical field of preparation of modified polytetrafluoroethylene materials, and in particular relates to a high-temperature wear-resistant material and a preparation method and application thereof.

Background technique

The statements herein merely provide background related to the present invention and do not necessarily constitute prior art.

Polytetrafluoroethylene (PTFE) has heat resistance, low temperature resistance, chemical resistance and electrical properties, and has excellent non-stick and self-lubricating properties, and is the resin with the lowest coefficient of friction. However, using it under special working conditions, especially in the environment of high temperature and high speed operation, will lead to poor high temperature wear resistance and serious wear and other problems.

Carbon fiber reinforced polymer composites have high specific strength and high specific modulus, good chemical stability and excellent tribological properties, which are widely used in various fields such as gears and bearings. The modification method of polytetrafluoroethylene in the prior art is difficult to effectively improve its high temperature wear resistance.

SUMMARY OF THE INVENTION

Aiming at the deficiencies in the prior art, the purpose of the present invention is to provide a high temperature wear-resistant material and a preparation method and application thereof.

In order to achieve the above object, the present invention is realized by the following technical solutions:

In the first aspect, the present invention provides a high-temperature wear-resistant material composition, which is composed of the following components in parts by weight: 3-10 parts of polyimide, 2-5 parts of carbon fiber, and 85-95 parts of polytetrafluoroethylene powder share.

In a second aspect, the present invention provides a method for preparing a high-temperature wear-resistant material, comprising the following steps:

The mass ratio of polyimide, carbon fiber and polytetrafluoroethylene powder is 3-7:

2-4: premix at 89-95 to obtain premixed powder;

The premixed powder is frozen and mixed at high speed to obtain a mixed powder;

Put the mixed powder into the mold and press it into a blank;

After sintering the blank, a shaped product is obtained.

In a third aspect, the present invention provides a high-temperature wear-resistant product prepared by the preparation method.

The beneficial effects obtained by one or more embodiments of the present invention are as follows:

The modified polytetrafluoroethylene fine powder resin, polyimide and carbon fiber are mixed uniformly at high speed according to different percentages. Polytetrafluoroethylene is conducive to the interface bonding of carbon fiber, which reduces the roughness of carbon fiber and reduces wear. Polyimide is conducive to the formation of transfer film, enhances the strength of the pair, and reduces the creep of the friction surface at high temperature.

The interface between the three composite materials is conducive to stress transmission and dispersion in the process of high temperature friction and wear. PTFE has appropriate resilience, which plays a good role in sealing, and will not damage the metal surface during the grinding process with metal parts. The characteristics help related components to be effective for a long time, and to exert good wear-resistant sealing performance under high temperature conditions.

It is especially suitable for sealing rings, piston rings, valves of high temperature medium on high temperature and high speed running equipment and other fields.

Description of drawings

The accompanying drawings forming a part of the present invention are used to provide further understanding of the present invention, and the exemplary embodiments of the present invention and their descriptions are used to explain the present invention, and do not constitute an improper limitation of the present invention.

Fig. 1 is the preparation process flow chart of the embodiment of the present invention;

Fig. 2 is the scanning electron microscope images of the composite materials prepared by Examples 1-3 of the present invention and Comparative Example 1, wherein (a) is the composite material prepared in Example 1, (b) is the composite material prepared in Example 2, ( c) is the composite material prepared in Example 3, (d) is the composite material prepared in Comparative Example 1.

Detailed ways

It should be noted that the following detailed description is exemplary and intended to provide further explanation of the invention. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

In the first aspect, the present invention provides a high-temperature wear-resistant material composition, which is composed of the following components in parts by weight: 5-10 parts of polyimide, 2-5 parts of carbon fiber, and 85-93 parts of polytetrafluoroethylene powder. share.

In some embodiments, the high temperature wear-resistant material composition consists of the following components by weight: 3-7 parts of polyimide, 2-4 parts of carbon fiber, and 85-95 parts of polytetrafluoroethylene powder.

Preferably, the high temperature wear-resistant material composition is composed of the following components in parts by weight: 3-7 parts of polyimide, 2-4 parts of carbon fiber, and 87-95 parts of polytetrafluoroethylene powder.

For example, polyimide can be 3 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts; carbon fiber can be 2 parts, 3 parts, 4 parts, 5 parts; polytetrafluoroethylene powder can be 85 parts 86, 87, 88, 89, 90, 91, 92, 95.

Polyimide refers to a class of polymers containing imide rings on the main chain. As a special engineering material, it has excellent mechanical properties and thermal stability, maintains good physical and mechanical properties in the temperature range of -270°C to 400°C, and can be used for a long time in the air of -240°C to 260°C. The thermal decomposition temperature is 600°C, which is one of the most thermally stable varieties of polymers so far.

Carbon fiber is a fiber with a diameter of about 4-10μm, mainly composed of carbon atoms, with high stiffness, high tensile strength, low weight, high chemical resistance, high temperature resistance and low thermal expansion, these characteristics make it widely used in reinforcement in composite materials.

Further preferably, the high temperature wear-resistant material composition is composed of the following components in parts by weight: 7 parts of polyimide, 4 parts of carbon fiber, and 89 parts of polytetrafluoroethylene powder.

In a second aspect, the present invention provides a method for preparing a high-temperature wear-resistant material, comprising the following steps:

Premixing polyimide, carbon fiber and polytetrafluoroethylene powder in a mass ratio of 3-7:2-4:85-95 to obtain premixed powder;

The premixed powder is frozen and mixed at high speed to obtain a mixed powder;

Put the mixed powder into the mold and press it into a blank;

After sintering the blank, a shaped product is obtained.

In some embodiments, the particle size of the polytetrafluoroethylene powder is 9-20 μm; the particle size of the polyimide is 10-40 μm; the diameter of the carbon fiber is 4-10 μm, and the length is 30-50 μm.

In some embodiments, the freezing temperature is -10 to -20° C., and the freezing time is 20-30 h.

Preferably, after freezing, the rotating speed of high-speed mixing is 2000-3000 r/min, and the mixing time is 2-10 min.

In some embodiments, the pressing pressure is 25-40 MPa.

In some embodiments, the sintering temperature is 360-380° C., and the holding time is 4-10 h.

In a third aspect, the present invention provides a high-temperature wear-resistant product prepared by the preparation method.

The present invention will be further described below in conjunction with the examples.

A: Required materials and material index parameters:

Modified polytetrafluoroethylene suspended fine powder: purchased from Shandong Dongyue Polymer Materials Co., Ltd., modified polytetrafluoroethylene suspended fine powder (brand DF161) resin as the main material has better properties than ordinary polytetrafluoroethylene suspended fine powder resin. High elongation and tensile strength, high pressure resistance, low penetration, relatively good particle flexibility, more oily, high resilience, better adhesion to dual seals, and better air tightness. The modified polytetrafluoroethylene suspended fine powder resin was sent to the cold storage for 24 hours. Then, jet pulverization is performed, and the particle size after pulverization is in the range of 9 μm-20 μm for use.

Polyimide molding powder: the particle size is about 10-40 μm, and the polyimide is dried in a sintering furnace at a temperature of 320° C. for 4 hours.

Carbon fiber powder: the particle size is about 4-10μm.

B: Required equipment: premixer, high-speed mixer, hydraulic press, sintering furnace, etc.

Polyimide carbon fiber modified polytetrafluoroethylene composite material, carbon fiber and polyimide are added to PTFE according to mass fraction respectively, the process flow chart is shown in Figure 1:

Example 1

The preparation method of high temperature wear-resistant polytetrafluoroethylene composite material comprises the following steps:

1) In the present invention, 7% of polyimide and 4% of carbon fiber are added to 89% modified polytetrafluoroethylene fine powder resin by mass percentage, and premixed for about 10 minutes. The cold storage is frozen for 24 hours, and the temperature in the cold storage is -20 °C;

Finally, the frozen material was stirred in a high-speed mixer at 3000 r/min for 10 minutes. A uniformly mixed composite resin powder is obtained.

2) In the method of powder metallurgy cold pressing, the composite resin powder is loaded into the mold, and pressed into a blank according to the pre-forming unit pressure of 35Mpa.

3) Put the preformed blank into an oven, sinter freely in the air, the sintering temperature rises and falls in a stepwise manner, the sintering temperature is 360-380° C., and the holding time is 6 hours to obtain a molded product.

Example 2

The preparation method of high temperature wear-resistant polytetrafluoroethylene composite material comprises the following steps:

1) Add 5% polyimide and 3% carbon fiber to 92% modified polytetrafluoroethylene fine powder resin, carry out premixing for 10 minutes, and send the premix to the cold storage for 24 hours, and the temperature in the cold storage is -15°C; finally, the frozen material was stirred in a high-speed mixer at 2500 r/min for 5 minutes. A uniformly mixed composite resin powder is obtained.

2) In the method of powder metallurgy cold pressing, the composite resin powder is loaded into the mold, and pressed into a blank according to the pre-forming unit pressure of 30Mpa.

3) Put the preformed blank into an oven, sinter freely in the air, the sintering temperature rises and falls in a stepwise manner, the sintering temperature is 360-380° C., and the holding time is 6 hours to obtain a molded product.

Example 3

The preparation method of high temperature wear-resistant polytetrafluoroethylene composite material comprises the following steps:

1) Add 3% polyimide and 2% carbon fiber to 88% modified polytetrafluoroethylene fine powder resin, carry out premixing for about 10 minutes, and send the premix to the cold storage for 24 hours. is -10℃;

Finally, the frozen material was stirred in a high-speed mixer at 2800 r/min for 3 minutes. A uniformly mixed composite resin powder is obtained.

2) In the method of powder metallurgy cold pressing, the composite resin powder is loaded into the mold, and pressed into a blank according to the pre-forming unit pressure of 28Mpa.

3) Put the preformed blank into an oven, sinter freely in the air, the sintering temperature rises and falls in a stepwise manner, the sintering temperature is 360-380° C., and the holding time is 6 hours to obtain a molded product.

Comparative Example 1

The difference from Example 1 is that polyimide is omitted, and the others are the same as Example 1.

Comparative Example 2

The difference from Example 1 is that carbon fiber is omitted, and other aspects are the same as Example 1.

Comparative Example 3

The difference from Example 1 is that polyimide and carbon fiber are omitted.

Performance check:

According to the standard:

ASTMD-4894-15 (tensile strength - elongation at break);

GB/T2411-2008 (Shore hardness);

HG/T2909-1997 (cleanliness);

GB/T3690-2007 (friction coefficient);

ASTMD792-2007 (specific gravity).

Test data analysis was carried out for each embodiment and comparative example of the high temperature wear-resistant composite material, and the results are shown in Table 1.

Table 1 Test data of each formula example of high temperature wear-resistant composite material

Through the test data analysis of each formula example of the high-temperature wear-resistant composite material in Table 1: from the examples 1-3 and the comparative examples 1-3, it can be seen that in the preparation process of the material, the rotation speed, time and freezing time of the high-speed mixer all affect the uniformity of the surface of the test material degree and coefficient of friction and tensile strength. The composite material formula and the applied unit square pressure will affect the hardness and specific gravity of the composite material. The hardness value of the material is an important indicator for evaluating the wear resistance and friction coefficient of the composite material.

Especially in Example 1, the proportion of polyimide is increased, and the thermal stability and physical and mechanical properties of polyimide in the polymer are fully exerted. The prepared composite material is especially suitable for the preparation of high temperature resistant medium valves. The sealing performance, air tightness and service life of the obtained high temperature medium valve are obviously enhanced, and the dimensional stability of the prepared high temperature medium valve is obviously improved. Even in a high temperature working environment such as 300 °C, the composite material is basically not deformed, and maintains good elasticity, which can achieve a good high temperature sealing effect.

The above description is only the preferred embodiment 1 of the present invention, and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (10)

1. A high-temperature wear-resistant material composition, characterized in that: it is composed of the following components in parts by weight: 5-10 parts of polyimide, 2-5 parts of carbon fiber, and 85-93 parts of polytetrafluoroethylene powder. 2. The high-temperature wear-resistant material composition according to claim 1, characterized in that: it is composed of the following components in parts by weight: 5-8 parts of polyimide, 2-4 parts of carbon fiber, polytetrafluoroethylene powder 85-90 servings. 3. The high-temperature wear-resistant material composition according to claim 2, wherein the high-temperature wear-resistant material composition is composed of the following components in parts by weight: 6-8 parts of polyimide, 3-8 parts of carbon fiber 4 parts, 87-90 parts of polytetrafluoroethylene powder. 4. The high-temperature wear-resistant material composition according to claim 3, wherein the high-temperature wear-resistant material composition is composed of the following components in parts by weight: 7 parts of polyimide, 4 parts of carbon fiber, 89 parts of tetrafluoroethylene powder. 5. a preparation method of high temperature wear-resistant material, is characterized in that: comprise the steps: Premixing polyimide, carbon fiber and polytetrafluoroethylene powder in a mass ratio of 5-10:2-5:85-93 to obtain premixed powder; The premixed powder is frozen and mixed at high speed to obtain a mixed powder; Put the mixed powder into the mold and press it into a blank; After sintering the blank, a shaped product is obtained. 6. The preparation method of high temperature wear-resistant material according to claim 5, characterized in that: the particle size of the polytetrafluoroethylene powder is 9-20 μm; the particle size of the polyimide is 10-40 μm; the diameter of the carbon fiber is 4 μm -10μm, 30-50μm in length. 7. The preparation method of high-temperature wear-resistant material according to claim 5, wherein the freezing temperature is -10～-20°C, and the freezing time is 20-30h; Or, after freezing, the rotating speed of high-speed mixing is 2000-3000 r/min, and the mixing time is 2-10 min. 8. The preparation method of high temperature wear-resistant material according to claim 5, wherein the pressing pressure is 25-40MPa. 9 . The method for preparing a high temperature wear-resistant material according to claim 5 , wherein the sintering temperature is 360-380° C., and the holding time is 4-10 h. 10 . 10. A high-temperature wear-resistant product, characterized in that it is prepared by the preparation method described in any one of claims 5-9.

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