The polycrystalline Ti/TiNx multilayer films were deposited by magnetron sputtering, and the as-deposited multilayer coatings were annealed at 500-800 degrees C for 2-4 h in vacuum. We investigated the effects of annealing temperature and annealing time on the microstructural, interfacial, and mechanical properties of the polycrystalline TiMNx multilayer films. It was found that the hardness increased with annealing temperature. This hardness enhancement was probably caused by the preferred crystalline orientation TiN(1 1 1). The X-ray reflectivity measurements showed that the layer structure of the coatings could be maintained after annealing at 500 degrees C and the addition of the Si3N4 interlayer to Ti/TiNx, multilayer could improve the thermal stability to 800 degrees C. (c) 2007 Elsevier B.V. All rights reserved.