Molybdenum nitride coatings were deposited onto high-speed steel (HSS) substrates by the arcPVD technique. It was possible to producecoatings with MO%N and MoN structure by varying the nitrogen partial pressure between 0.4 and 1.5 Pa. The relationships between hardness, thickness, and crystallographic structure of the coating and the deposition parameten were investigated. Hardness of the coatings increased with the increase of nitrogen content of the coating. Tribological behavior of the coatings was detennined by ball-on-disk wear tests. The wear behavi~ of Mo-N~oated HSS samples against alumina balls was better than that of TIN-coated ~Electrochemical polarization experiments were conducted in 1 N sulfuric acid. The porosity of the samples was detemtined by the copper decoration test The coating with the lowest nitrogen content showed the best com)Sjon protective properties in the electrochemical tests. C 1997 Elsevier Science SA. TE 79 多軸摩擦磨損試驗(yàn)機(jī)