Coated silicon nitride based cutting tools
AssigneeSandvik AB
InventorMarian Mikus
Life of this patent
Estimating the term…
Abstract
The present invention relates to coated silicon nitride based cutting tools and a method of making the same. By a carburizing heat treatment prior to the deposition of the coating, an improved bonding strength of the coating is obtained. A continuous or semicontinuous transition zone of 2-10 μm thickness is formed between the substrate and the inner layer of the coating in which transition zone the glass phase is replaced by the material of the inner layer.
Claims7
A silicon nitride based cutting tool comprising a silicon nitride containing substrate including a glass phase, a single or multilayer outer coating and a continuous or semicontinuous transition zone of 2-10 μm thickness between the substrate and the inner layer of the outer coating in which transition zone the glass phase is replaced by the material of the inner layer.
A method of making a coated silicon nitride based cutting tool comprising a substrate and a single or multilayer outer coating comprising treating the substrate in a carburizing atmosphere at 850-1375° C. and thereafter depositing the single or multilayer coating.
Dependencies are inferred from the claim text.