Kev soj ntsuam luv luv ntawm cov khoom tsim ua ke nrog cov khoom sib txhuam
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.
Cov txheej txheem kev paub tab ntau dua hauv kev ua haujlwm ntawm cov hmoov hlau metallurgy cov ntaub ntawv sib txhuam yog embodied nyob rau hauv patents tau los ntawm Willman thiab nws cov npoj yaig hauv Tebchaws Meskas thaum xyoo 1937-1941. Qhov no patent siv tin bronze raws li cov hlau matrix ntawm cov khoom sib txhuam, thiab tin bronze tuaj yeem ua alloyed nrog zinc. Hlau thiab silica yog ntxiv los ua kom cov coefficient ntawm kev sib txhuam, thiab graphite thiab txhuas yog ntxiv rau lubricating Cheebtsam.
Txog ib lub sij hawm ntawm 1950-1980, hmoov metallurgy kev sib txhuam cov ntaub ntawv tau ntse siv nyob rau hauv qhuav kev sib txhuam thiab ntub kev sib txhuam chaw ua hauj lwm. Nws daim ntawv thov thaj chaw tau nthuav dav rau cov brakes thiab clutches rau cov tsheb nruab nrab thiab hnyav, tshuab ua liaj ua teb, thiab lwm yam. Txij li xyoo 1958, British Frood Company tau koom tes nrog American SK Wellman Company thiab Bendix Aviation los tsim bronze -raws li, hlau{ {4}}raws li thiab ceramic-raws li cov ntaub ntawv sib txhuam.