The aim of the study was to investigate the influence of cerium ion implantation on the oxidation behavior of ZrN coating. Samples was deposited by cathodic arc deposition and subsequently implanted with different doses of cerium using a MEVVA ion implanter. The ions were extracted with a voltage of 40 kV, and the dose ranged from 5 x 10(16) to 2 x 10(17) s/cm(2) The air oxidation behaviors at 500 degreesC of as-deposited and Ce-implanted ZrN coatings were characterized by weight gain measurement. The oxidation resistance of ZrN coating reduced after implantation with cerium at low dose but rebounded at higher dose. The oxidation rate of ZrN coatings were 2.18 x 10(-7), 5.21 x 10(-8), 4.18 x 10(-7) and 1.56 x 10(-7) mg(2) cm(-4) s(-1) with dose of 0, 5 x 10(16), 1 x 10(17) and 2 x 10(17) ions/cm(2). X-ray photoelectron spectroscopy and glancing angle X-ray diffraction were employed to analyze the valence states of the oxide scale and the phase composition of the oxidation layers, respectively. Cerium implantation could improve the oxidation resistance of ZrN coating with higher dose. Finally, the mechanism of the oxidation behavior is discussed. (C) 2004 Elsevier B.V. All rights reserved.