Metallic coatings thermal spray

Svuface treatments discussed in this article include scale removal, polishing, btiffing, plating, conversion coatings, thermal spray, vapor deposition, and thermomechanical surface treatment. Titanium alloys generally do not reqvdre special surface treatments to improve corrosion resistance, because their resistance to many corrosive environments is excellent. However, titanium is coated or plated with corrosion-resistant metals (e.g., copper and platinum) as an alternative to oxide formation. 

Each type of metallic coating process has some sort of hazard, whether it is thermal energy, the reactivity of molten salt or metal baths, particulates in the air from spray processes, poisonous gases from pack cementation and diffusion, or electrical hazards associated with arc spray or ion implantation. 

Coating metal surfaces with water-impermeable barriers (such as paint, epoxies, thermal sprays, grease, and oil)... 

Protecting a surface from corrosion by coating can be accomplished by a number of well-established processes which include paints, metal plating (with zinc or cadmium), diffusion, thermal spraying, and, more recently, vapor deposition processes. Of these physical vapor deposition (PVD) is used extensively in corrosion protection. Typical applications are ... 

Thermal spray is a well-established, relatively low-cost, industrial processes which is used widely for the deposition of metals and compounds, including the refractory carbides and nitrides. Examples are coatings of tungsten carbide with a cobalt binder which are of major industrial importance. PI... 

Most metals and many refractory compounds can be thermal-sprayed. Applications include coating of gas-turbine components for aircraft and industrial use, components of steam turbines and diesel engines, components for the oil and gas industry, paper and pulp industry, and chemical processing industry. 

An ideal bond coat should have several characteristics that include uncompromised biocompatibility, good adhesion to both the metal substrate and the osseoconductive top coat, and a well-defined melting point to allow application of thermal spray technology. The adhesive function of the bond coat has been loosely compared to the action of a double-sided adhesive tape. 

This technique originally developed to determine the efficacy of shot peening applied to induce compressive stresses at the surface of metallic work pieces has been adapted to thermally sprayed thin coatings (Knight and Smith, 1993). A thin test strip is being mounted on a holder (SAE Handbook, 1977) and blasted with shot. This treatment leads to curving after removal from the fixture. The peened... 

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