Microstructure and Wear Behavior of Single layer (CrN) and Multilayered (SiN/CrN) Coatings on Particulate Filled Aluminum Alloy Composites

Abstract

This article presents the slurry erosive wear behavior of single and multilayer coatings on granite powder reinforced aluminum alloy composites for hydro-turbine blade material. The composites were fabricated by stir casting technique with different weight fraction (0, 2, 4, 6wt.%) of granite powder in 1050 aluminum alloy. In this study, the slurry jet erosive performance of uncoated, single layer and multilayer coating granite powder filled alloy composites in a slurry jet wear test was conducted for four different operating parameters such as filler content (0-6wt.%), impact velocity (10-25 m/s), impingement angle (30-75 0) and erodent discharge (160-280 gm), respectively. The slurry erosion rate was a maximum at 0wt.% granite powder reinforcement in uncoated, single layer and multilayer coating samples such as: 0.0203 gm/kg, 0.00981 gm/kg and 0.00756 gm/kg, respectively at impact velocity of 25 m/sec. Taguchi’s orthogonal array (L 16) was applied to study the experimental results of the uncoated and coated alloy composites. A correlation was derived from the results of the Taguchi experimental design and a proposed predictive equation for estimation of slurry erosion rate of these composites. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) were conducted to analyze the topography of the eroded surface of uncoated and coated granite powder reinforced aluminum alloy composites.