Effect of electron beam remelting treatments on the performances of plasma sprayed zirconia coatings

Highlights: • The scanning electron beam was used to post treat zirconia as-sprayed coatings. • Microstructure of the coating changed from lamellar to columnar structure. • Porosity of the coating was reduced about 20% after the remelting treatments. • Microhardness of the coating had nearly doubled after the remelting treatments. • Wear behaviors of the coating was improved significantly. In this study, zirconia coatings were deposited on stainless steel using air plasma spraying (APS), and electron beam remelting treatments (EBRTs) were used to improve the performances of the plasma sprayed coatings. The properties of the zirconia coatings such as porosity, microhardness, surface roughness, phase transformation and wear behaviors were characterized and measured. The experimental results showed that electron beam treatments of the plasma sprayed coatings generated a compact remelted layer on top of the surface composed of columnar structure. EBRTs significantly reduced the porosity and surface roughness. The surface microhardness had also nearly doubled after EBRTs. Compared with the as-sprayed zirconia coating, wear behaviors of the electron beam treated coatings had considerably improved.