Hybridized-flow flame spray (HFFS) process for the development of superior ceramic coatings

Abstract

The present study deals with a novel, effective and single step thermal spray coating process development. The process is named as ‘Hybridized-Flow Flame Spray (HFFS) process’. The process is very much suitable for the development of ceramic coatings with superior properties when compared to conventional Powder Flame Spray (PFS) coatings. The HFFS process is capable in addressing the shortcomings (porosity, density, hardness, surface quality) of PFS coatings. The physical, mechanical and metallurgical analysis of PFS and HFFS coatings are done using density measurement kit, 3-D optical profilometer, Vickers and scratch hardness, and scanning electron microscope (SEM). The results show significant improvement in the properties. The increment in density (≈24%), hardness (Vickers ≈ 37% and scratch ≈ 126%); and decrement in coating thickness (≈35%) and average surface roughness (≈47%) of HFFS sprayed coatings are observed. The results are benchmarked with those of PFS coatings. The improved responses are attributed to the densification of coating structure and improved microstructural changes due to the presence of hybridized flow in the HFFS.