State of the Art of HVOF Coating Investigations—A Review

Corrosion, erosion and abrasion, or combinations of these mechanisms, are the main cause of degradation of materials used in marine, aircraft, waste incinerators, power generation, chemical, and paper and pulp industries. One possible way to address these problems is by applying a thin layer of wear and corrosion resistant coatings. Due to the continuously rising cost of materials as well as increased material requirements, coating techniques have been given more importance in recent times. Among the different coatings techniques, high velocity oxy-fuel (HVOF) spraying process is a new and rapidly developing technology, which can yield high density coatings with porosity less than 1%, having high hardness and adhesion values, and good erosion, corrosion and wear resistance properties. The very high kinetic energy of the powder particles in the HVOF process results in the deposition of high quality coatings. It is possible to obtain a coating thickness of more than 1.5 mm with careful control of cooling to reduce residual stresses. The purpose of this paper is to review the physical, mechanical, erosion-corrosion and wear properties of the HVOF coatings and effects of deposition parameters of the process on the properties of the coatings.