AFM Study of Ultrafine Tungsten Carbide-Cobalt Cemented Carbide

Nanocrystalline tungsten carbide-cobalt composite powders prepared spray pyrogenation-continuous reduction and carbonization technology are consolidated by sinterhip. The topographies, grain size distribution and microstructure limitation of ultrafine tungsten carbide-cobalt cemented carbide are observed using atomic force microscope (AFM), and mechanical properties are also investigated. Results show that ultrafine tungsten carbide-cobalt cemented carbide with average grain size of less than 220nm, transverse rupture strength (TRS)of more than 3300 MPa and Rockwell A hardness of more than 93.5 is achieved. Although microstructure of ultrafine cemented carbide prepared by nanocrystalline tungsten carbide-cobalt composite powder is homogeneously, but there are a lot of microstructure limitation, and this paper analyses their forming mechanisms.