PVD CVD TECHNOLOGY FOR COATING CEMENTED CARBIDES/

The results of examinations of an intermediate layer between the TiN c oating obtained by physical vapor deposition (PVD) and the cemented-ca rbide substrate show the presence of the TiC coating and the decarboni zed eta-phase underlayer after carrying out bombardment of the substra te with Ti ions. A new PVD technology, which allows elimination of the decarbonization or damage of the cemented carbide substrate, is used for depositing a special barrier underlayer before deposition of the c onventional coating by chemical vapor deposition (CVD). The PVD-CVD co ating produced by use of the technology does not lead to a decrease in the transverse rupture strength and toughness of the coated cemented carbides and allows a high level of wear resistance of the conventiona lly CVD coated cemented carbides to be achieved. The PVD-CVD coated cu tting inserts have a longer tool lifetime in milling and approximately the same tool lifetime in turning compared with the conventionally CV D coated inserts.