An Evaluation of the Adhesive Strength of the Interface between a Coating and Substrate

• Published in: JSME International Journal Series A Solid Mechanics and Material Engineering Vol. 46; no. 3; pp. 335 - 340
• Main Authors: MIYASHITA, Yukio, SASAKI, Yu, KUROISHI, Tomoaki, WATANABE, Takanori, XU, Jin-Quan, MUTOH, Yoshiharu, YASUOKA, Manabu
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Tokyo The Japan Society of Mechanical Engineers 01.07.2003; Japan Society of Mechanical Engineers; Japan Science and Technology Agency
• Subjects: Adhesive Strength; Ceramic Coating; Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Fatigue, brittleness, fracture, and cracks; FEM; Mechanical and acoustical properties; Mechanical and acoustical properties of condensed matter; Mechanical properties of solids; Physical properties of thin films, nonelectronic; Physics; Scratch Test; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); TiC; TiN
• ISSN: 1344-7912; 1347-5363
• DOI: 10.1299/jsmea.46.335

Scratch tests were carried out on TiC and TiN coatings which had been deposited by PVD (Physical Vapor Deposition) and CVD (Chemical Vapor Deposition) techniques. The critical load Lc was detected by the acoustic emission method (AE) and also by the frictional force curve. The critical load corresponded to the load at which local delamination of coating was observed on the scratch track. A study the scratch tracks induced in a coating during the scratch test revealed that fine cracks, which propagated parallel to the scratch track, were created before local delamination occurred. Other cracks, which propagated perpendicular to the scratch direction, were observed to form in the scratch track at the critical load. Localized delamination also occurred at the edge of scratch track at Lc. The stress distribution at the interface was estimated by FEM (Finite Element Method) analysis. From both the experimental and analytical results, it was found that local delamination occurred at a critical shear stress at the interface between coating and substrate. Since the shear stress at the interface decreased with decreasing tangential force, the critical load Lc increased with decreasing of tangential force. Indentation tests without tangential force was also carried out. The critical load was higher in the indentation test compared to that in scratch test. However, the critical shear stresses at the interface for both scratch and indentation tests coincided with each other. It was concluded that the adhesive strength between coating and substrate is a function of the critical interfacial shear stress.