The effect of a metal vapor vacuum arc (MEVVA)-implanted Cr interlayer on the microstructure of the CrN coating on the silicon wafer was investigated. Two types of the CrN-coated specimens were prepared with and without an MEVVA-implanted Cr interlayer-CrN/Cr/Si and CrN/Si-by cathodic arc plasma deposition. Both specimens of the same batch were annealed at 500 degreesC for 2 h in an N-2/H-2 atmosphere, to elucidate the thermal stability of the CrN film. The columnar structure of CrN/Cr/Si was observed by cross-sectional transmission electron microscopy. The X-ray diffraction results revealed the presence of CrN, and that (2 2 0) is the preferred orientation of both CrN/Si and CrN/Cr/Si. However, CrN/Si revealed a phase transformation from CrN to Cr2N during annealing, which is due largely to stress relaxation in the film. A MEVVA-implanted Cr interlayer can effectively relax the residual stress in the growing CrN of the coating and prevent a phase transformation in the CrN/Cr/Si assembly during annealing. (C) 2003 Elsevier B.V. All rights reserved.