Development of Iron Based Brake Friction Material by Hot Powder Preform Forging Technique used for Medium to Heavy Duty Applications

摘要

A promising friction material, Iron -based friction material, was prepared by powder metallurgy (PM) processing utilizing hot powder preform forging (near net-shape).The preparation of the product and its characterization are presented in this paper. These products are useful in heavy duty Military Aircraft applications such as AN-32. In order to eliminate costly environmental control systems to protect products during their high temperature processing (as is conventionally practiced employing hydrogen gas), the present investigation relies on carbon (mixed in the brake pad formulation) as reducing agent and high temperature oxidation resistant glassy coating (separately developed) applied over the product’s surface after cold compacting. After conducting an initial characterization such as hardness, density and Pin-on Disc tests, the samples were tested in sub-scale dynamometer under Rejected Take Off conditions. It was observed that the obtained density in the present investigation is higher than the reported density obtained by sintering route, and wear is on the lower side of the range as per the Aeronautical Standards. Optical metallography was used to investigate the microstructure of friction, interface and backing layer. It was observed that the distribution of ingredients in matrix was homogeneous. The results also indicate that the coefficient of friction is more stable, and wear is lower with respect to temperature rise. .