TRIBOLOGICAL BEHAVIOUR OF RAPID SOLIDIFIED H-Al-17Si ALLOY WITH CrN + a-c: H (DLC-STAR) COATING USING HFRR

The present work deals with the tribological behavior of rapid solidified hyper eutectic AlSi17Cu3.5-4Mg0.6-0.8 alloy produced with the rheo-stir squeeze casting method under T-6 condition. However, for experimental studies, HFRR (high frequency linear reciprocating rig) with a ball-on-plate geometry is used. At different loading (5-30N) conditions, friction and wear characteristics of rapid solidified AlSi17Cu3.5-4Mg0.6-0.8 (H-Al-17Si) alloy are investigated under dry, lubricated (SAE15W40), and coated dry (DLC-Star) sliding conditions. It is found that for dry and lubricated sliding, COF values of hypereutectic H-Al-17Si alloy are 0.41 and 0.064. A lower friction coefficient value of 0.023 was recorded with DLC-star coating under dry conditions. Whereas, the least wear coefficient is also observed with DLC-star (CrN + a-c: H) coating compared to the lubricated (SAE15W40) and dry sliding conditions. The wear coefficient of H -Al-17Si specimens' first increases with applied load (5 N to 20 N) and then decreases from 20 N to 30 N loads. Surface morphologies were examined using SEM, AFM, surface roughness profilometer, and advanced metallurgical microscope (AMM) analysis techniques. The advancements in wear and friction coefficients were primarily ascribed to the dispersion and size of primary Si granules and the development of tribo-oxide films on the H-Al-17Si alloy coated surfaces.