Microstructure and Mechanical Properties of Multilayer alpha-AlN/alpha-BCN Coating as Functions of the Current Density during Sputtering of a B4C Target

摘要

Multilayer AlN/BCN coating of nanometer scale have been prepared by magnetron sputtering of Al and B4C targets in an argon-nitrogen atmosphere during deposition on a Si substrate. These coating have an X-ray amorphous structure and the maximum Knoop hardness of 27 GPa (at the current density 100 mA). The first-principle molecular dynamics calculations show that the B4-BN layer is dynamically unstable; thus, it will not be epitaxial and will be amorphous or have a structure different from the B4-BN structure. The thermal vacuum annealing from 600 to 800 degrees C of samples with multilayer nanosized coating leads to the decrease in the Knoop hardness to 18 GPa; however, the coating structure is retained X-ray amorphous.