abstract |
An improved multilayer alumina coated cemented carbide insert is made by depositing on the substrate a kappa -alumina layer, wet blasting the surface of that insert and then heat-treating the resulting insert at 900 DEG C.-1100 DEG C. for 0.3-10 hours to convert the kappa -alumina to alpha -alumina. One or more further alumina layers can then be applied. |