日本金属学会誌

J. Japan Inst. Metals, Vol. 48, No. 2 (1984),
pp. 214-219

The Interfacial Structure and Transverse-Rupture Strength of Cemented Carbides Coated with Titanium Nitride by Ion Plating (PVD) Process

Hisashi Suzuki1, Koji Hayashi2, Hideaki Matsubara1 and Kunio Shibuki3

1Department of Metallurgy and Materials Science, Faculty of Engineering, The University of Tokyo, Tokyo
2Institute of Industrial Science, The University of Tokyo, Tokyo
3Toshiba Tungaloy Co. Ltd., Kawasaki

Abstract:

A titanium nitride layer was deposited mainly onto HIP-treated WC-10%Co substrate by ion plating (PVD) process at 773 K. The structure at an interface between substrate and layer, and the transverse-rupture strength (TRS) of the coated alloy were examined as a function of the layer thickness (≤sssim5 μm), the surface state of substrate (ground or polished) etc. The effect of annealing of the coated alloy on the structure and strength was also examined.
It was found that a foreign phase having no definite crystal structure formed generally at the interface. The thickness of this phase (≤sssim0.5 μm) did not vary with the layer thickness, but with the surface state of substrate. The foreign phase changed to η (Co3W3C) by annealing at 1073--1173 K. The foreign phase formation would be due to the diffusion of carbon atoms in the substrate near the interface into the coated layer. The TRS of the coated allays decreased with increasing thickness of the layer, showing that the adhesion between substrate and layer was sufficient by the formation of non-equilibrium phase as above. The TRS was higher, when the substrate surface was in a ground state. When the coated alloys were annealed, the TRS decreased with increasing annealing temperature. It was shown that the fracture of the coated alloys generally took place at the moment of fracture of the coated layer, in other words, the TRS of the coated alloys was mainly controlled by the strength of layer.


(Received 1983/08/26)

Keywords:

cemented carbide, ion plating process, physical vapor deposition process, titanium nitride, strength, interface, coating, tool material, adhesion


PDF(Free)PDF (Free)     Table of ContentsTable of Contents

Please do not copy without permission.