| abstract |
The compact contains by vol. 20-95%, esp. 30-70% diamond powder with particle size 1 mu m, the remainder being a carbide binder, viz WC or (MoW)C, also with size 1 mu m and pref. cemented. The carbide may also contain 50 vol.% TaC, ZrC, HfC, TiC or NbC. The diamond powder is pref. obtd. by milling in a carbide mill with carbide balls, where the carbide is WC or (MoW)C; and a powder(a) is added to the mill to cause abrasion of the carbide lining and the balls, thus providing a powder mixed with the diamond; a carbide powder may also be added to the mill prior to milling. The powder mixt. is then degassed in vacuo at >300 degrees C., and hot pressed to mfr. the compact. The powder mixt. may be cold compacted before vacuum degassing. Used to obtain a cutting tool with increased working life, providing a very smooth surface finish on workpieces, e.g. Cu alloys or Al-Si alloys. |