Fiber-reinforced copper-based brake pad for high-speed railway train, and preparation and friction braking performance thereof

Patent metadata

Field	Value
Publication number	US-11852209-B2
Application number	US-202016793938-A
Country	US
Kind code	B2
Filing date	Feb 18, 2020
Priority date	Dec 5, 2018
Publication date	Dec 26, 2023
Grant date	Dec 26, 2023

Abstract

The present disclosure relates to a fiber-reinforced copper-based brake pad for high-speed railway train, and preparation and friction braking performance thereof. The fiber-reinforced copper-based brake pad for high-speed railway train comprises 80-98.5 wt. % metal powder, 1-15 wt. % non-metal powder and 0.5-5 wt. % fiber component. In addition, some components are added in a specific proportion to achieve optimal performance. The copper-based powder metallurgy brake pad is obtained by powder mixing, cold-pressing and sintering with constant pressure. The friction braking performance of the obtained brake pad is tested according to a braking procedure consisting of three stages, i.e., the first stage with low-pressure and low-speed, the second stage with high-pressure high-speed and the continuous emergency braking third stage with high-pressure and high-speed. The brake pad has advantages including higher and more stable friction coefficient, higher fade and wear resistance and slighter damage to brake disc at high speeds.

First claim

What is claimed is:

1. A fiber-reinforced copper-based powder metallurgy brake pad for high-speed railway train, wherein the composition of the copper-based powder metallurgy brake pad comprises metal powder, non-metal powder and a fiber component;
the weight percentage of the metal powder is 80-98.5%;
the weight percentage of the non-metal powder is 1-20%; and the weight percentage of the fiber component is 0.5-5%;
wherein the weight percentages of the components of the metal powder are as follows: copper powder: 45-65%; iron powder: 15-30%; anatase titanium dioxide powder: 1-10%; molybdenum disulfide powder: 1-5%; chromium powder: 1-10%; high carbon ferrochrome powder: 1-10%; the particle size of the copper powder is 48-75 μm; the particle size of the iron powder is 45-150 μm; the particle size of the titanium oxide powder is less than 10 μm, the particle size of the molybdenum disulfide powder is 45-150 μm; the particle size of the chromium powder is 10-48 μm; and the particle size of the high carbon ferrochrome powder is 10-48 μm.

2. The fiber-reinforced copper-based powder metallurgy brake pad according to claim 1 , wherein: the weight percentages of the components of the non-metal powder are as follows: flake graphite powder: 1-10%; granular graphite powder: 1-10%; the particle size of the flake graphite powder is 180-380 μm; and the particle size of the granular graphite powder is 106-300 μm.

3. The fiber-reinforced copper-based powder metallurgy brake pad according to claim 1 , wherein: in a case that the fiber component is one of rigid aluminum oxide fibers, silicon carbide fibers or flexible carbon fibers: wherein, the weight percentage of the fiber component is 1-5% if aluminum oxide fibers are selected, and the weight percentage of the fiber component is 0.5-3% if silicon carbide fibers or carbon fibers are selected.

4. The fiber-reinforced copper-based powder metallurgy brake pad according to claim 3 , wherein: in a case that the fiber component is a mixture of rigid aluminum oxide fibers or silicon carbide fibers and flexible carbon fibers; the ratio of the rigid aluminum oxide fibers or the silicon carbide fibers to the flexible carbon fibers is 1:0.5˜1:1; and the weight percentage of the mixed fibers is 1-4%.

5. The fiber-reinforced copper-based powder metallurgy brake pad according to claim 4 , wherein: the constituents of the fiber component are as follows: aluminum oxide fibers with diameter of 5-20 μm and length of 10-100 μm; silicon carbide fibers with diameter of 0.1-0.5 μm and length of 10-50 μm; carbon fibers with diameter of 0.2-0.6 μm and length of 5-50 μm.

6. The fiber-reinforced copper-based powder metallurgy brake pad according to claim 5 , wherein: the length-diameter ratio of the rigid aluminum oxide fibers is 5:1˜20:1; and the length-diameter ratio of the rigid silicon carbide fibers or flexible carbon fibers is 10:1˜100:1.

7. The fiber-reinforced copper-based powder metallurgy brake pad according to claim 2 , wherein: the weight ratio of the granular graphite powder to the flake graphite powder is 1:1˜1:1.5.

8. The fiber-reinforced copper-based powder metallurgy brake pad according to claim 1 , wherein: the weight ratio of the chromium powder to the high carbon ferrochrome powder is 1:1˜1:1.5.

9. A method for preparing a fiber-reinforced copper-based powder metallurgy brake pad for high-speed railway train, wherein the composition of the copper-based powder metallurgy brake pad comprises metal powder, non-metal powder and a fiber component;
the weight percentage of the metal powder is 80-98.5%;
the weight percentage of the non-metal powder is 1-20%; and the weight percentage of the fiber component is 0.5-5%;
comprises the following steps:
step I. mixing of powder: loading raw material powder at a preset component mixture ratio into a double-cane atomizing mixer; turning on a heat transfer oil pump; heating up a mixing cylinder to 80-140° C.; dissolving a binder in a solvent at the temperature of 60-100° C. to form a binder solution; heating up the binder solution to 80-120° C.; carrying the binder solution with a gas at 0.1 MPa-1 MPa pressure for loading the binder solution into the double-cane atomizing mixer; adding the binder solution into a continuously rolling material by atomizing and spraying; mixing the material and the binder solution for 6-10 h to obtain binder-treated powder;
step II. pressing of powder: molding the binder-treated powder by cold-press molding at the pressure of 400-500 MPa to obtain a cold-pressed compact; and
step III. sintering of brake pad: sintering the cold-pressed compact in a hot-pressed sintering furnace at the sintering temperature of 850° C.-950° C. and hot pressing pressure of 2 MPa-4 MPa for 60-120 min, in a mixed sintering atmosphere composed of hydrogen and nitrogen; cooling down the compact to a temperature lower than 100° C. at a constant pressure, and then taking out the compact; thus, a sintered copper-based brake pad is obtained.

10. The method according to claim 9 , wherein the weight percentage of components of the binder is: ethylene bis-stearamide, 40-70%; paraffin, 10-20%; polyamide wax, 15-30%; lauric acid, 2-5%; stearic acid, 20-40%; isooctanoid acid, 2-5%; and polymethacrylate, 5-10%.

11. The method according to claim 9 , wherein the solvent is n-heptane; the binder content in the binder solution is 0.1-0.7 wt. %; and the dissolving temperature of the binder is 60-100° C.

12. The method according to claim 9 , wherein: the weight percentages of the components of the metal powder are as follows: copper powder: 45-65%; iron powder: 15-30%; anatase titanium dioxide powder: 1-10%; molybdenum disulfide powder: 1-5%; chromium powder: 1-10%; high carbon ferrochrome powder: 1-10%; the particle size of the copper powder is 48-75 μm; the particle size of the iron powder is 45-150 μm; the particle size of the titanium oxide powder is less than 10 μm, the particle size of the molybdenum disulfide powder is 45-150 μm; the particle size of the chromium powder is 10-48 μm; and the particle size of the high carbon ferrochrome powder is 10-48 μm.

13. The method according to claim 9 , wherein: the weight percentages of the components of the non-metal powder are as follows: flake graphite powder: 1-10%; granular graphite powder: 1-10%; the particle size of the flake graphite powder is 180-380 μm; and the particle size of the granular graphite powder is 106-300 μm.

14. The method according to claim 9 , wherein: in a case that the fiber component is one of rigid aluminum oxide fibers, silicon carbide fibers or flexible carbon fibers: wherein, the weight percentage of the fiber component is 1-5% if aluminum oxide fibers are selected, and the weight percentage of the fiber component is 0.5-3% if silicon carbide fibers or carbon fibers are selected.

15. The method according to claim 14 , wherein: in a case that the fiber component is a mixture of rigid aluminum oxide fibers or silicon carbide fibers and flexible carbon fibers; the ratio of the rigid aluminum oxide fibers or the silicon carbide fibers to the flexible carbon fibers is 1:0.5˜1:1; and the weight percentage of the mixed fibers is 1-4%.

16. The method according to claim 15 , wherein: the constituents of the fiber component are as follows: aluminum oxide fibers with diameter of 5-20 μm and length of 10-100 μm; silicon carbide fibers with diameter of 0.1-0.5 μm and length of 10-50 μm; carbon fibers with diameter of 0.2-0.6 μm and length of 5-50 μm.

17. The method according to claim 16 , wherein: the length-diameter ratio of the rigid aluminum oxide fibers is 5:1˜20:

Assignees

• Univ Beijing Science & Technology
• Beijing Tianyishangjia New Mat Corp Ltd

Inventors

• Zhang Lin
• Qu Xuanhui
• Zhang Peng
• Wu Peifang
• Qin Mingli
• Shijia Cairang
• Cao Jingwu
• Fu Kangxi

Classifications

• F16D69/028 Primary

  containing fibres · CPC title

• B22F1/10

  Metallic powder containing lubricating or binding agents; Metallic powder containing organic material · CPC title

• B22F1/108

  Mixtures obtained by warm mixing · CPC title

• B22F3/16

  in successive or repeated steps · CPC title

• B22F7/008

  characterised by the composition · CPC title