Multilayer Cr(1-x)AlxN films with a total thickness of 2 mu m were deposited on high-speed steel by medium frequency magnetron sputtering from Cr and Al-Cr (70 at.% Al) targets. The samples were annealed in air at 400 degrees C, 600 degrees C, 800 degrees C and 1000 degrees C for I hour. Films were characterized by cross-sectional scanning electron microscopy and X-ray diffraction analysis. The grain size of the as-deposited multilayer films is about 10 nm, increasing with the annealing temperature up to 100 nm. Interfacial reactions have clearly changed at elevated annealing temperatures. As-deposited films' hardness measured by nanoindentation is 22.6 GPa, which increases to 26.7 GPa when the annealing temperature goes up to 400 and 600 degrees C, but hardness decreases to 21.2 GPa with further annealing temperature increase from 600 to 1000 degrees C. The multilayer film adhesion was measured by means of the scratch test combined with acoustic emission for detecting the fracture load. The critical normal load decreased from 49.7 N for the as-deposited films to 21.2 N for the films annealed at 1000 degrees C. (C) 2011 Elsevier B.V. All rights reserved.