Research On Preparation And Properties Of Copper-based Powder Metallurgy High-speed Train Pad Materials

Disc type brake as the high-speed train mechanical friction brake, is important to ensure a train finally realizes the essential parking brake in the case of dynamic braking failure, and it is one of the most key skills to keep safe in the running of high speed train. The friction property of the brake pad as a side of the friction pair directly determines the braking efficiency. At present, development on the high-speed train brake pad is still in experimental stage in China, and active brake mainly relys on imports. This article studies the preparation and properties of copper-based powder metallurgy high-speed train braking pad in this background.According to the researches at home and abroad this article, choosed the right materials through the study in experiment, prepared the Cu-based brake pad by powder metallurgy technology. We measured the physical and mechanical properties of them, and observed their microstructure, analysed of their composition and structure, tested their friction and wear properties by the MMl000-II machine.The results showed that, the wrap of cupper on ferric which is used to prepare the Cu-based powder metallurgy brake pad can effectively improve the physical mechanical properties and friction wear properties of materials; Ca F2 did not have the effect of lubrication and reduced the mechanical properties of materials under 150km/h, but it had a collaborative effect of lubrication with graphite,and reduced the wear loss under 250km/h. But the friction and wear performance of the Cu-based powder metallurgy brake pad which had the CaF2 powder had a big difference in low-speed and high-speed, so CaF2 as a solid lubricant, cannot be used to prepare the high-speed powder metallurgy brake pad. Compared with the commercial pad, We found that the Cu-based powder metallurgy brake pad which we prepared had a higher density and brinell hardness, a appropriate friction coefficient, a larger wear loss. Thier performance did not reach the using performance of the commercial pad. The effect of the distribution of metal powder, reasonable lubricant content and particle size on the properties of brake pad material needs to be investigated in following researches. It is hoped we can prepare the Cu-based powder metallurgy brake pad which properties like the commercial properties.