Coatings

Abstract

CoatingsCoated WC-Co hard metals have found wide applicability since the 1970's. The demand for the same has increased considerably and new processes have been devised to overcome the shortcomings of one or another process. Coatings provided to WC-Co hard metals are of various forms: TiC, Ti(C,N), TiN, HfN, A1203. etc., either singly or in combinations of some of these. Coated WC-Co hard metal offers various advantages over uncoated ones:[~]: 9 They can be used at higher speeds than uncoated cutting tools and thereby provide a higher metal removal rate 9 They have higher wear resistance than uncoated tools 9 Higher chemical stability of coated layer compounds in comparison to WC, and the chemical breakdown of the coating near the cutting edges is reduced 9 Extended service life lowers tool and regrinding costs 9 Larger tool-change intervals lead to reduced machine downtime 9 Improved surface quality makes further operations easier or even superfluous and reduces manufacturing cost 309