| 摘要 |
<p>A sintered hard metal product, e.g. a disposable cutting insert for use in the machining of metals, consisting of a cemented metal carbide substrate and a thin wear-resistant surface coating comprising a plurality of coating layers of different compositions applied on to at least a part of the surface of said substrate and on top of each other by chemical vapour deposition, characterized in that said coating layers include:
<UnorderedLists id="ula01" listStyle="none"><ListItem>an innermost layer applied directly onto said substrate and consisting of at least one member selected from carbides, nitrides and carbonitrides of Ti, Zr, Hf, V, Nb, Ta, AI and Si;</ListItem><ListItem>a second layer applied directly on said innermost layer, consisting essentially of aluminium oxide and having a thickness of about 1 to about 3p; and</ListItem><ListItem>a third layer composed of one or more sub-layers of titanium carbide, titanium nitride and titanium carbonitride, applied on top of said aluminium oxide layer. Said coating layers may further include an outermost layer consisting essentially of aluminium oxide and having a thickness of from about 0.4 to about 20 microns. Preferably, the total thickness of said surface coating is less than 20 microns.</ListItem></UnorderedLists></p> |
