TiN and CrN coatings were deposited on 1040 carbon steel substrates by arc-PVD. Coated materials were then subjected to heating at 600 and 650 degrees C in vacuum for 1 h. As-coated and heat-treated samples were characterized with respect to their hardness and thickness. Electrochemical polarization experiments were conducted on the samples in 1 N sulfuric acid. Porosity of the samples was determined by means of a copper decoration test. EDS line-scan analyses were performed on the fracture surfaces of the coatings. It was found that heating decreased the hardness, increased the number of pores extending through the coating and improved the corrosion-protective properties of the coated materials. CrN-coated samples exhibited better corrosion-protective properties than TiN-coated steels. (C) 1997 Elsevier Science S.A.