WC-based thermally sprayed coatings are now widely used in a range of industries to improve the mechanical strength of the components, but also enhance the resistance of the substrate to wear and corrosion. High velocity oxygen fuel thermal spraying has been accepted as a pre-eminent technology to deposit composite coatings with high density, superior bond strengths and relatively low decarburization due to the high particle velocities and relatively low particle temperatures induced in the deposition process. Many types of tungsten carbide/metal cermet coatings have been developed by alloying with different chemical elements, in an attempt to enhance corrosion and even erosion-corrosion resistance of coatings produced by HVOF for industrial applications, for example oil and gas industries. In this paper the galvanic series and the erosion-corrosion behaviour of three types of tungsten carbide coatings and three different sealing technologies in simulated oil and gas industry environments are compared. The ultimate goal is to have an understanding of how optimum choice of coating for a given application can be made for applications in the oil and gas industry.

Damage of marine screw propeller parts made of aluminum bronze cast material caused by cavitation erosion is one of the serious problems. Erosion resistant thermal spray coating on aluminum-bronze material is expected to extend lifetime of such propellers. In this study, Cobalt-based alloy coatings sprayed by; (a) atmospheric plasma spraying (APS), (b) low pressure plasma spraying (LPPS) and (c) high velocity oxy-fuel (HVOF) spraying and aluminum bronze cast material were evaluated by cavitation erosion test using magnetostrictive cavitation test equipment. Fracture morphology of cavitation eroded coating surfaces were analyzed by surface observations with SEM and also the amount of volume loss was measured. Cobalt-based alloy coatings sprayed by LPPS exhibited superior cavitation erosion resistance compared to aluminum bronze cast material and coatings by APS and HVOF. Moreover, mechanical properties of Cobalt-based alloy coatings were investigated in detail by nanoindentation technique. It is found that cavitation erosion resistance of coatings is subjected to interparticle cohesive strength.

During the past 20 years, Technogenia Inc. has imposed laser cladding for the enhancement of wear parts and repairs under the trade name of LASERCARB. In spite of the technical differences and advantages, laser cladding has been perceived as a competitive technology to thermal spraying. However, it has had a slow acceptance in the surface engineering industry. This article is a technical and economical update on LASERCARB. New laser, processed materials, capabilities, performances and trends are presented. Economical approaches include background market analysis, cost analysis and technology cost trend. Finally, a processes comparison eases the positioning technology to each other and highlights supplemental aspects.