Tribological Properties of Aluminum Alloy treated by Fine Particle Peening/DLC Hybrid Surface Modification

¹ Graduate School of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kouhoku-ku, Yokohama-shi, Kanagawa, 223-8522, Japan
² RIKEN, 2-1, Hirosawa, Wako-shi, Saitama, 351-0198, Japan
³ Department of Mechanical Engineering, Keio University, 3-14-1, Hiyoshi, Kouhoku-ku, Yokohama-shi, Kanagawa, 223-8522, Japan

^a e-mail : komotori@mech.keio.ac.jp

Abstract

In order to improve the adhesiveness of the DLC coating, Fine Particle Peening (FPP) treatment was employed as pre-treatment of the DLC coating process. FPP treatment was performed using SiC shot particles, and then AA6061-T6 aluminum alloy was DLC-coated. A SiC-rich layer was formed around the surface of the aluminum alloy by the FPP treatment because small chips of shot particles were embedded into the substrate surface. Reciprocating sliding tests were conducted to measure the friction coefficients. While the DLC coated specimen without FPP treatment showed a sudden increase in friction coefficient at the early stage of the wear cycles, the FPP/DLC hybrid treated specimen maintained a low friction coefficient value during the test period. Further investigation revealed that the tribological properties of the substrate after the DLC coating were improved with an increase in the amount of Si at the surface.