Impact of surface roughness and preheat temperature on fecrbmnsi coating properties prepared by the twin wire Arc spray method.

The purpose of this study is to evaluate the effects of substrate surface roughness (35 μm and 40 μm) and preheat temperature (50 °C, 100 °C, 150 °C) on the properties of the FeCrBMnSi coating layer applied to 304 stainless steels using the TWAS (Twin Wire Arc Spray) method. Surface preparation involved sandblasting and preheat treatment, followed by coating application with TWAS, and subsequent characterization using pull-off bonding, hardness, corrosion rate, Light Optical Microscope (LOM), and scanning electron microscopy (SEM) test. The current study's findings indicate that increasing preheat temperature and surface roughness consistently reduces the percentage of porosity, unmelted material, and coating layer thickness. This enhances the hardness and adhesive strength of the coating layers. The hardness of the coating layer obtained in the present study was improved by 360-439% compared to the uncoated material. The best specimen in this study was found on a substrate with a surface roughness of 40 μm and performed a preheating treatment at a temperature of 150 °C. The thickness of the coating layer for this specimen was 150.58 × 10⁻³ mm, with a porosity and unmelted materials of 7.233%, a hardness of 1114.6 HV, an adhesive strength of 20.29 MPa, and a corrosion rate of 1.0640 × 10⁻² mmpy. However, the corrosion resistance of the coated specimens remains lower than that of the uncoated 304 stainless steel.