Influence of Structure on Brittleness of Boron Nitride Coatings Deposited on Cemented Fine-Grained Carbides

摘要

The article presents the brittleness study of boron nitride coatings deposited on cutting edges made of fine-grained cemented carbides by the pulse-plasma method (PPD). Influences of the structure (density, pores, microcracks) of coating material on the brittleness and on selected technological parameters of boron nitride formation by PPD method particularly taking into account discharge voltage on brittleness are shown. Differences between values of total average crack length ∑L, critical loads (P_(k300), P_(k500)). and coefficients (a_(1(300)) and a_(1(500))) characterized susceptibility to cracking of investigated coatings manufactured using different values of production process were defined. Results of investigations have confirmed the usefulness of Palmqvist's method for measurement of coating susceptibility to brittle cracking.