阅读说明：本技术 一种喷涂Cr3C2-NiCr涂层的碳纤维纸基摩擦材料及其制备方法 (Spray coating Cr3C2Carbon fiber paper-based friction material with-NiCr coating and preparation method thereof ) 是由 王士华 张国亮 龙柱 胡爱林 李志强 桑明珠 郭帅 李广斌 于 2020-07-29 设计创作，主要内容包括：本发明公开了一种喷涂Cr<Sub>3</Sub>C<Sub>2</Sub>-NiCr涂层的碳纤维纸基摩擦材料及其制备方法,属于纸基复合材料技术领域。本发明方法采用无机纤维和有机纤维混合,实现相互协同作用,提高了摩擦磨损性能；本发明对Cr<Sub>3</Sub>C<Sub>2</Sub>-NiCr粉末进行喷涂,利用其优异的耐热、耐高温氧化和耐腐蚀性能,和碳纤维纸基材料复合,制备出性能优异的纸基摩擦材料,具有化学性能稳定好、尺寸稳定性好、膨胀系数小、耐滑动磨损和抗微动磨损性能优异、重量轻的优点,是制备密封环、刹车片的理想材料。(The invention discloses a Cr spraying method 3 C 2 A carbon fiber paper-based friction material with a NiCr coating and a preparation method thereof, belonging to the technical field of paper-based composite materials. According to the method, the inorganic fibers and the organic fibers are mixed, so that mutual synergistic effect is realized, and the frictional wear performance is improved; the invention is to Cr 3 C 2 The paper-based friction material with excellent performance is prepared by spraying NiCr powder and compounding the NiCr powder with carbon fiber paper-based materials by utilizing the excellent heat resistance, high-temperature oxidation resistance and corrosion resistance of the NiCr powder, has the advantages of good chemical stability, good dimensional stability, small expansion coefficient, excellent sliding wear resistance and fretting wear resistance and light weight, and is an ideal material for preparing sealing rings and brake pads.)

1. Preparation of spray-coated Cr₃C₂-a method of NiCr coated carbon fiber paper based friction material characterized in that it comprises the following steps:

spraying Cr on the surface of the paper pattern₃C₂-NiCr coating, i.e. obtaining sprayed Cr₃C₂-a NiCr coated carbon fiber paper based friction material; wherein the spraying thickness is 0.1-0.5 mm.

2. The method of claim 1, wherein the spray coating process is: the flow rate of oxygen is 800-1000L/min, the flow rate of kerosene is 4-6 g/h, and the spraying distance is 200-400 mm.

3. The method of claim 1, wherein Cr is present₃C₂The mass ratio of the NiCr to the NiCr is 25-75%: 25 to 75 percent.

4. The method of claim 1, wherein Cr is present₃C₂The particle size of the particles is 20-40 mu m; the particle size of the NiCr is 20-40 μm.

5. The method according to claim 1, characterized in that the preparation method of the pattern comprises:

(1) pretreating carbon fibers: soaking the carbon fiber in one of concentrated nitric acid and hydrochloric acid solution for 1-3 h, and cleaning; and (3) performing pretreatment on the PEEK fiber: soaking the PEEK fiber in 5-20% sulfuric acid or hydrochloric acid and 5-20% sodium hydroxide for 1-3 h; mixing the treated carbon fibers and PEEK fibers, and defibering the fibers for 15-30 min to obtain a mixed fiber suspension;

(2) mixing the fiber suspension, pulp after beating and filler Al₂O₃、SiO₂Uniformly mixing graphite and a friction performance regulator to obtain a mixed slurry suspension; wherein the adding amount of the pulp is 10-50% of the mass of the mixed pulp, and the mass ratio of the mixed fiber to the pulp is 1: 1; filler Al₂O₃、SiO₂The total addition amount of the graphite is 0.5-5% of the mass of the mixed slurry, and the mass ratio of the graphite to the mixed slurry is 1:1: 1; the addition amount of the friction performance regulator is 0.5-5% of the mass of the mixed slurry;

(3) carrying out papermaking wet forming, dewatering and drying treatment on the mixed slurry suspension obtained in the step (2) to obtain base paper;

(4) diluting the polyetheretherketone resin into resin solution by using a diluent, dipping base paper in the polyetheretherketone resin solution, drying and hot-pressing to obtain a paper pattern.

6. The method of claim 5, wherein the molar ratio is greater than the molar ratioThe wiping performance regulator is BaSO₄One or more of diatomite and kaolin.

7. The method of claim 5, wherein the carbon fibers have a length of 3 to 6 mm; the length of the PEEK fiber is 3-6 mm.

8. The method according to claim 1, characterized in that it comprises in particular the steps of:

(1) pretreating carbon fibers: soaking the carbon fiber in one of concentrated nitric acid and hydrochloric acid solution for 1-3 h, and cleaning; and (3) performing pretreatment on the PEEK fiber: soaking the PEEK fiber in 5-20% sulfuric acid or hydrochloric acid and 5-20% sodium hydroxide for 1-3 h; mixing the treated carbon fibers and PEEK fibers, and defibering the fibers for 15-30 min to obtain a mixed fiber suspension;

(2) mixing the fiber suspension, pulp after beating and filler Al₂O₃、SiO₂Uniformly mixing graphite and a friction performance regulator diatomite to obtain a mixed slurry suspension; wherein the adding amount of the pulp is 10-50% of the mass of the mixed pulp, and the mass ratio of the mixed fiber to the pulp is 1: 1; filler Al₂O₃、SiO₂The total addition amount of the graphite is 0.5-5% of the mass of the mixed slurry, and the mass ratio of the graphite to the mixed slurry is 1:1: 1; the addition amount of the frictional property regulator diatomite is 0.5-5% of the mass of the mixed slurry;

(3) carrying out papermaking wet forming, dewatering and drying treatment on the mixed slurry suspension obtained in the step (2) to obtain base paper;

(4) diluting the polyetheretherketone resin into resin solution by using a diluent, soaking base paper in the polyetheretherketone resin solution, drying and hot pressing;

(5) spraying Cr on the dipped paper pattern₃C₂-NiCr coating, i.e. obtaining sprayed Cr₃C₂-NiCr coated carbon fiber paper based friction material.

9. Spray coating obtainable by a process according to any one of claims 1 to 8Cr₃C₂-NiCr coated carbon fiber paper based friction material.

10. Sprayed Cr of claim 9₃C₂-application of carbon fiber paper-based friction material with NiCr coating in seal ring and brake pad.

Technical Field

The invention relates to a Cr spraying coating₃C₂A carbon fiber paper-based friction material with a NiCr coating and a preparation method thereof, belonging to the technical field of paper-based composite materials.

Background

Friction materials are widely used in power machines, and the friction materials absorb or transmit power through friction to realize braking and transmission functions, and include brake linings (brake pads) and clutch plates. The paper-based friction material is a wet friction material with porosity, oil absorption, easy compression and excellent resilience performance, mainly comprises fibers, a bonding agent, a filler, a friction performance regulator and the like, is usually made into raw paper of the paper-based friction material by a papermaking method, and is impregnated with resin to generate the paper-based friction material. The paper-based friction material has been developed into a more and more important wet friction material which gradually replaces resin-based and metal-based friction materials due to the advantages of low production cost, stable dynamic friction factor, approximate dynamic/static friction factor ratio, stable bonding performance, low wear rate, long service life, low noise, capability of protecting dual materials and the like.

The carbon fiber is used as a hot door fiber of the current friction material, has the advantages of stable friction coefficient, static/dynamic friction coefficient ratio close to 1, excellent self-lubricating property, good thermal conductivity, extremely high mechanical strength and wear resistance, good chemical stability, no softening, melting, carbonization and the like under high temperature conditions, is gradually applied to the paper-based friction material, but has low chemical activity and surface activity, is difficult to be wetted and uniformly dispersed by water, has poor flexibility relative to aramid fiber, is contacted and lapped with carbon fibers with different orientations, forms a large number of pores with different sizes in the paper-based friction material, and leads the uniformity of the paper-based friction material to be poor, thereby leading the stability of the paper-based friction material to be reduced; secondly, the carbon fiber composite material has the defects of lack of ductility, easy breakage, difficult recycling of carbon fibers and the like, and the application of the carbon fiber composite material in certain fields is limited.

The polyether-ether-ketone fiber (PEEK fiber) is a wholly aromatic fiber and has ether bonds and ketone bonds, so that the high-temperature resistance, friction resistance and corrosion resistance of the fiber are far higher than those of conventional fibers, and the fiber has extremely excellent comprehensive performance. Under higher temperature conditions, outstanding wear rates and low coefficients of friction can still be maintained due to good tribological properties and excellent self-lubricity. The tensile strength of the composite material can reach 700MPa, the modulus is 3-6 GPa, and the composite material can be used for manufacturing an engine inner cover, an automobile bearing, a sealing element, a brake pad and the like in the automobile industry due to excellent friction resistance, high temperature resistance, easy processing and other good performances. Because the PEEK fiber has excellent performances such as friction resistance, high temperature resistance, corrosion resistance and the like, the PEEK fiber is applied in many fields, but still has some defects, and because the PEEK molecular chain is rigid and nonpolar, the PEEK molecular chain has poor wettability with the fiber and weak bonding force with the fiber, the average length, the fiber content and the fiber distribution of the fiber in the composite material obtained by adopting an injection molding process are uneven, so that the friction resistance of the composite material is poor; the performance of the prior art is increased by increasing the strength of the reinforcing material, but the production cost is greatly increased. CN104927298A discloses a preparation method of a polyether ether ketone based wear-resistant composite material, which is characterized in that polyetherimide PEI coated carbon fibers and coupling agent modified TiO₂And stirring and mixing the polyether-ether-ketone at a high speed, drying and injection molding. The prepared composite material has poor fiber dispersibility, poor nanoparticle uniformity and easy shedding. CN206054734U discloses a preparation method of a polyether-ether-ketone sealing element, which is complex in preparation method, only requires polyether-ether-ketone resin as a raw material,low elastic modulus and large elongation under stress. The paper-based friction material is formed by a papermaking wet method, the fibers and the filler are uniformly dispersed, the uniformity of the material is improved, the porosity is stable, and the mechanical strength and the friction performance of the friction material are greatly improved. However, when the paper-based friction material works at a continuous high temperature, the components of the friction material can be melted by heat, and the wear resistance of the friction material is greatly reduced.

Cr₃C₂NiCr is one of the most widely used cermets at present, and is composed of a metal alloy binder phase NiCr and a ceramic hard phase Cr₃C₂The composite material has the characteristics of high hardness, good wear resistance, good corrosion resistance and excellent high-temperature oxidation resistance of ceramic, has the characteristics of high metal-based toughness and the like, is the most important high-temperature wear-resistant coating, and is widely applied to continuous casting and rolling rollers and surface high-temperature wear-resistant coatings. Cr (chromium) component₃C₂The NiCr wear-resistant coating can reduce the wear of the equipment parts caused by the erosion of materials, and can improve the service life of the paper-based friction material while ensuring the friction performance. Patent CN110079756A discloses a method for preparing a nickel-chromium carbide wear-resistant coating, which adopts an argon arc welding machine to carry out NiCr and Cr₃C₂And performing TIG remelting treatment on the powder, and spraying the nickel-chromium carbide wear-resistant coating on the carbon steel, 45 steel or alloy steel base material. The wear-resistant coating prepared by the method has excellent friction performance, particularly under the high-temperature condition, but the preparation process is complex and has higher requirements on equipment.

At present, Cr in the existing patent₃C₂Most of the NiCr high-temperature-resistant wear-resistant coatings are applied to the surfaces of carbon steel, 45 steel or alloy steel, and the high-performance coatings are less researched when being compounded on paper-based friction materials and the like.

Disclosure of Invention

In order to solve at least one of the above problems, the present invention provides a Cr spray coating₃C₂Preparation method of carbon fiber paper-based friction material with NiCr coating and prepared Cr spraying coating₃C₂-NiCarbon fiber paper-based friction material with Cr coating, Cr₃C₂The NiCr wear-resistant coating can be mechanically engaged with the modified carbon fiber and the resin base material, so that the binding force among the components is enhanced, and meanwhile, the Cr is₃C₂The existence of the NiCr wear-resistant coating obviously improves the high temperature resistance of the friction material, greatly ensures the friction stability of the friction material under the high temperature condition, ensures that the prepared paper-based friction material has the advantages of good chemical property stability, good dimensional stability, small expansion coefficient, excellent sliding wear resistance and fretting wear resistance and light weight, and is an ideal material for preparing sealing rings and brake pads.

The first purpose of the invention is to provide a method for preparing spray-coated Cr₃C₂-a method of NiCr coated carbon fiber paper based friction material, said method comprising the steps of:

spraying Cr on the surface of the paper pattern₃C₂-NiCr coating, i.e. obtaining sprayed Cr₃C₂-a NiCr coated carbon fiber paper based friction material; wherein the spraying thickness is 0.1-0.5 mm.

In one embodiment of the invention, the thickness of the spray coating is 0.4 mm.

In one embodiment of the present invention, the spraying process is: the flow rate of oxygen is 800-1000L/min, the flow rate of kerosene is 4-6 g/h, and the spraying distance is 200-400 mm.

In one embodiment of the present invention, the spraying process is: the oxygen flow is 900/min, the kerosene flow is 6g/h, and the spraying distance is 300 mm.

In one embodiment of the present invention, Cr₃C₂The mass ratio of the NiCr to the NiCr is 25-75%: 25 to 75 percent.

In one embodiment of the present invention, Cr₃C₂The mass ratio of the precursor to NiCr is 75%: 25 percent.

In one embodiment of the present invention, Cr₃C₂The particle size of the particles is 20-40 mu m; the particle size of the NiCr is 20-40 μm.

In one embodiment of the present invention, Cr₃C₂The particle size of the NiCr particles was 30 μm.

In one embodiment of the present invention, the preparation method of the paper pattern comprises:

(1) pretreating carbon fibers: soaking the carbon fiber in one of concentrated nitric acid and hydrochloric acid solution for 1-3 h, and cleaning; and (3) performing pretreatment on the PEEK fiber: soaking the PEEK fiber in 5-20% sulfuric acid or hydrochloric acid and 5-20% sodium hydroxide for 1-3 h; mixing the treated carbon fibers and PEEK fibers, and defibering the fibers for 15-30 min to obtain a mixed fiber suspension (the concentration is 0.2-1.2%);

(2) mixing the fiber suspension, pulp after beating and filler Al₂O₃、SiO₂Uniformly mixing graphite and a friction performance regulator diatomite to obtain a mixed slurry suspension; wherein the adding amount of the pulp is 10-50% of the mass of the mixed pulp, and the mass ratio of the mixed fiber to the pulp is 1: 1; filler Al₂O₃、SiO₂The total addition amount of the graphite is 0.5-5% of the mass of the mixed slurry, and the mass ratio of the graphite to the mixed slurry is 1:1: 1; the addition amount of the friction performance regulator is 0.5-5% of the mass of the mixed slurry;

(3) carrying out papermaking wet forming, dewatering and drying treatment on the mixed slurry suspension obtained in the step (2) to obtain base paper;

(4) diluting the polyetheretherketone resin into resin solution by using a diluent, dipping base paper in the polyetheretherketone resin solution, drying and hot-pressing to obtain a paper pattern.

In one embodiment of the invention, the mass ratio of carbon fibers to PEEK fibers is 1-2: 1-2.

In one embodiment of the present invention, the carbon fiber has a length of 3 to 6 mm; the length of the PEEK fiber is 3-6 mm.

In one embodiment of the present invention, the pulp is one of aramid pulp, polysulfone pulp, and cotton pulp.

In one embodiment of the present invention, the filler is nano-Al₂O₃、SiO₂One or more of vermiculite and flake graphite.

In one embodiment of the invention, the friction performance modifier is BaSO₄One or more of diatomite and kaolin.

In one embodiment of the present invention, the diluent used for diluting the polyimide resin is N, N dimethylacetamide, acetone; the concentration of the polyether-ether-ketone resin solution is 10-30%.

In an embodiment of the present invention, the method specifically includes the following steps:

(1) pretreating carbon fibers: soaking the carbon fiber in one of concentrated nitric acid and hydrochloric acid solution for 1-3 h, and cleaning; and (3) performing pretreatment on the PEEK fiber: soaking the PEEK fiber in 5-20% sulfuric acid or hydrochloric acid and 5-20% sodium hydroxide for 1-3 h; mixing the treated carbon fibers and PEEK fibers, and defibering the fibers for 15-30 min to obtain a mixed fiber suspension;

(2) mixing the fiber suspension, pulp after beating and filler Al₂O₃、SiO₂Uniformly mixing graphite and a friction performance regulator diatomite to obtain a mixed slurry suspension; wherein the adding amount of the pulp is 10-50% of the mass of the mixed pulp, and the mass ratio of the mixed fiber to the pulp is 1: 1; filler Al₂O₃、SiO₂The total addition amount of the graphite is 0.5-5% of the mass of the mixed slurry, and the mass ratio of the graphite to the mixed slurry is 1:1: 1; the addition amount of the friction performance regulator is 0.5-5% of the mass of the mixed slurry;

(3) carrying out papermaking wet forming, dewatering and drying treatment on the mixed slurry obtained in the step (2) to obtain base paper;

(4) diluting the polyetheretherketone resin into resin solution by using a diluent, soaking base paper in the polyetheretherketone resin solution, drying and hot pressing;

(5) spraying Cr on the dipped paper pattern₃C₂-NiCr coating, i.e. obtaining sprayed Cr₃C₂-NiCr coated carbon fiber paper based friction material.

The second purpose of the invention is to prepare the spray-coated Cr prepared by the method of the invention₃C₂-NiCr coated carbon fiber paper based friction material.

Third object of the inventionThe invention is the spray coating Cr₃C₂-application of carbon fiber paper-based friction material with NiCr coating in seal ring and brake pad.

The invention has the following beneficial effects:

(1) the reinforced fiber raw material of the composite material prepared by the invention is formed by mixing inorganic fiber (carbon fiber) and organic fiber (PEEK fiber) to form an integral uniform mixed fiber material, so that the mutual synergistic effect can be realized, and the frictional wear performance can be improved.

(2) In the invention, Cr₃C₂The NiCr coating and the paper-based friction material are compounded, so that the synergistic effect of the wear-resistant coating and the paper-based friction material can be exerted, the heat resistance, high-temperature oxidation resistance and corrosion resistance of the composite material are obviously improved, the friction performance stability of the friction material under the high-temperature condition is ensured, and the pore structure of the material is also ensured.

(3) Cr in the invention₃C₂The NiCr wear-resistant coating is physically meshed with carbon fiber/polyether ether ketone fiber in the paper-based friction material to fill partial pores on the surface, so that the combination between the coating and the paper-based friction material is enhanced, and the wear resistance and the stability are improved.

(4) The preparation method adopts a method combining wet forming and hot pressing in papermaking to prepare the carbon fiber/polyether-ether-ketone fiber composite material, and can realize controllability on the fiber length, content, fiber distribution and resin dispersion uniformity in the high-performance fiber composite material; meanwhile, the process flow is simple, the production cost is low, and the method is suitable for industrial production.

(5) The spray coating Cr prepared by the invention₃C₂The carbon fiber paper-based friction material with the NiCr coating has the advantages of good chemical property stability, good size stability, small expansion coefficient, excellent sliding wear resistance and fretting wear resistance and light weight, and is an ideal material for preparing sealing rings and brake pads.

Detailed Description

The test method comprises the following steps:

(1) the method for measuring the tensile index is measured according to the national standard GB/T2914-2008.

(2) The burst index is determined according to the national standard GB/T454-2002.

(3) The tear index is determined according to the national standard GB/T455-2002.

(4) According to the requirements of QC/T583-1999 method for testing the apparent porosity of the automobile brake lining, an oil absorption method is adopted to test the porosity of the sample, and the porosity is calculated according to the formula:

in the formula: p- -porosity,%;

G₁-dry sample weight, g;

G₂-weight in oil of saturated oil sample, g;

G₃weight of saturated sample in air, g.

(5) And (3) measuring the friction coefficient:

the coefficient of dynamic friction is expressed by the following formula

Wherein: mu.s_d-coefficient of dynamic friction;

M_dmoment of kinetic friction, Nxm

P- -load of friction pair end face, N

R_CP- -effective radius of the sample, cm

The coefficient of static friction is expressed by the following formula

Wherein: mu.s_j-coefficient of static friction;

M_j- -moment of static friction, Nxm

P- -load of friction pair end face, N

R_CP- -effective radius of the sample, cm

R₁And R₂Respectively is the excircle and the inner circle radius of the sample friction material, the unit: cm.

(6) The wear rate calculation formula is as follows:

wherein: v- -wear rate, cm³/J；

A- -area of contact of sample, cm²；

Delta h- -thickness difference, cm, before and after wear of friction material

n- -number of brake clutching

I₀-total inertia of the tester, kg x m²，I₀Calculated by the following formula:

I₀＝I₁+I₂

I₁tester spindle inertia, I₁＝0.035kg×m²

I₂Tester configuration inertia, I₂＝0.2kg×m²。

Omega- -initial braking angular velocity, rad/s.