Hot Corrosion Behavior of Plasma-Sprayed WC-CoCr Coatings on AISI 316L Steel Substrate in Na2SO4-25% NaCl Salt Environment

• DOI: 10.1007/s11085-023-10162-6
• Publication Date: 2023-04-21T19:01:48Z
• Authors: Md Sarfaraz Alam; Anil Kumar Das
• Keywords: Thermogravimetric analysis; Weight change

This study investigates the hot corrosion resistance characteristics of plasma-sprayed WC-CoCr coatings deposited on AISI 316L stainless steel. Coated and uncoated samples were exposed to a fused Na2SO4-25%NaCl salt deposit at 700 °C in cyclic conditions for fifty thermal cycles. The kinetics determined using thermogravimetric method. To determine rate, weight-change measurements taken after every cycle. X-ray diffraction, energy dispersive spectroscopy, scanning electron microscopy performed examine characteristics. With °C, steel substrate experienced faster high-temperature oxidation as compared coated samples. It was noticed that gained little weight during first few cycles, afterwards number cycles increased, gain followed linear kinetics. coating reduced by about 75% corrosive environment. had adhesion strength microhardness 10.8 ± 2.4 MPa 410 25 HV0.5, respectively. corrosion-affected displayed slow-scaling oxides coatings, formed surface rich chromium tungsten. These helped providing environment they worked obstacles penetration/diffusion elements through coatings. higher content tungsten inside promoted WO3 formation, which improved elevated temperatures. Chromium caused formation spinel CoCr2O4 Cr2O3 emerged an intermediate phase also contributes maintenance resistance. Some such Fe2O3, FeCr2O4, CoSO4 found. Apart from some traces Na