Plasma spraying is a versatile technique for applying protective coatings to engineering alloys. The process can be used to apply many different metallic and nonmetallic materials to practically any substrate metal. However, plasma sprayed coatings generally exhibit a residual porosity because the molten droplets deposited by the plasma cool so rapidly that they cannot flow and completely wet the surface. Thus, small voids are trapped as the coating builds up droplet by droplet. These residual pores often limit the utility of plasma sprayed coatings for corrosion control applications because corrosive fluids can penetrate through the pores and attack the substrate material. Recent advances in plasma spraying technology have limited the number of trapped voids in some coatings, but even so the interparticle bonding is relatively weak.
In the present work, a high energy laser has been used to remelt and consolidate the pores in a plasma sprayed titanium coating on...
