Brief analysis of materials developed together with friction materials
At the same time as the development of organic friction materials, another type of friction material that is more commonly used is powder metallurgy friction materials. Before 1929, the Soviet Union's Schwarzkopf applied for the first patent for a sintered material for friction. The material was an alloy containing a small amount of lead, tin and copper. The United States also started the research of this work in 1929. In the late 1930s, the material was first used on the clutch plates of D-7 and D-8 scrapers. The American General Company organized the production of sintered materials for clutch plates in 1932, which was adopted by the aviation industry at that time.
The more mature basic process principle in the field of powder metallurgy friction materials is embodied in the patents obtained by Willman and his colleagues in the United States between 1937-1941. This patent uses tin bronze as the metal matrix of the friction material, and tin bronze can be alloyed with zinc. Iron and silica are added to increase the coefficient of friction, and graphite and lead are added as lubricating components.
About a period of time between 1950-1980, powder metallurgy friction materials were successfully used in dry friction and wet friction workplaces. Its application areas are expanded to brakes and clutches for medium and heavy vehicles, agricultural machinery, etc. Since 1958, the British Frood Company has cooperated with the American S.K. Wellman Company and Bendix Aviation to produce bronze-based, iron-based and ceramic-based friction materials.