Microwave cladding of NiCrSiC-5Al2O3 on austenitic stainless steel to improve cavitation erosion resistance

Abstract

The current investigation aimed to study the cavitation erosion performance of the microwave synthesized NiCrSiC-5Al2O3 composite clad with a 900 W power multimode domestic microwave applicator of 2.45 GHz frequency. The clads were deposited on the austenitic grade stainless steel, namely AISI-316. The as-deposited composite clad’s microstructure, crystal structure, porosity, microhardness, and flexural strength were examined. Cavitation erosion study was done using the vibratory cavitation method at varying standoff distance (SOD)-(0.5 mm, 1 mm, 1.5 mm) and vibration amplitude (AMP)-(40 μm, 50 μm, 60 μm), keeping other parameters constant. The results had shown that the deposited NiCrSiC-5Al2O3 composite clad exhibited 1.20% porosity, 489.16 ± 47.95 HV0.3 microhardness, 264.91 ± 4.5 MPa flexural strength, and performed 3.5 times much better than the AISI-316 in terms of cavitation resistance. The least weight loss occurred at 1.5 mm SOD and 40 μm AMP, where the highest weight loss was observed at 0.5 mm SOD and 60 μm AMP. The erosion mechanism of the NiCrSiC-5Al2O3 composite clad surface was observed as plastic deformation followed by surface fatigue; the clad surface was eroded in the form of pits, craters, impingement marks, secondary cracks, and plastically deformed lips.