The crystalline structure, hardness and thermal stability of AlN/CrN superlattice coating prepared by DC magnetron sputtering

Abstract

AIN/CrN nanoscale multilayered superlattice coatings have been deposited on M2 HSS by reactive D.C. magnetron sputtering with Al and Cr targets under Ar and N-2 atmosphere. The bilayer period of the coatings was controlled from 2.0 nm to 11.7 nm by changing rotation speed of the substrate holder. The crystalline structures of the AIN and CrN single layer were wurtzite and B1, respectively, whereas the AIN/CrN nanoscale multilayered superlattice coatings were stabilized to B I structure, irrespective of bilayer period within the experimental parameter range. The maximum hardness, 40 GPa, could be obtained for the AIN/CrN nanoscale multilayered superlattice coating with the bilayer period of 3.8 mn, which is much higher than those of AIN and CrN single layer coatings. After heat-treatment at high temperatures in air, the AIN/CrN nanoscale multilayered superlattice coatings have shown excellent oxidation resistance compared with AIN and CrN single layers. (c) 2005 Elsevier B.V All rights reserved.