Influence of Post-Heat Treatment on the Characteristics of FeCrBMnSi Coating on Stainless Steel 304 Substrate Prepared by Twin Wire Arc Spray (TWAS) Method at Various Stand-off Distance

Abstract

Twin wire arc spray (TWAS) is a type of thermal spray coating technology that has been extensively researched to improve the service life and overcome wear, cavitation and corrosion in pump impellers. This study aims to investigate the effect of post-heat treatment on the properties of FeCrBMnSi coatings fabricated by the Twin Wire Arc Spray (TWAS) method on 304 stainless steel substrates with varying stand-off distances. NiAl and FeCrBMnSi were employed as bond coats and top coats in this study. The substrate material was sandblasted before the coating process to achieve a surface roughness of 75-100 µm. The TAFA 9000 Electrical Wire-Arc Spraying machine's voltage (V), current (A), and compressed air pressure (Bar) were set to 28.4; 150; and 5, respectively. The coating operation was performed at 100, 200, and 300 mm stand-off distances. The specimens were then post-heated for 3 hours at 500°C and 700°C in a Thermolyne F6010 Furnace Chamber. The quality of the coating produced in this study was evaluated using thickness, hardness, wear, bond strength, micrography, and SEM (Scanning Electron Microscope) testing. According to the findings of this study, specimens with a stand-off distance of 100 mm and a post-heat treatment temperature of 700 o C produce the best coating qualities when compared to other specimens. This specimen resulted in a percentage of porosity and unmelted material, thickness, hardness, adhesive strength, and total wear rate of 7.1%, 5.53 x 10 -1 mm, 1460 HV, 24.86 MPa, and 3.8 x10 -4 mm 3 /s, respectively.