Corrosion Properties of Selected Coatings Produced by Atmospheric Plasma Spraying, HVOF and Laser Remelt Methods

摘要

The demand for high quality coatings, which are able to withstand the most extreme circumstances, are permanent. The span goes from equipment used in food production and pharmaceutical industry to more harsh environments, such as, offshore and power plant applications. The motivation is to expand service life, reduce shut down time and minimize potential migration of component material to products. Often a combination of several material properties are needed, which can be translated to a non-existing material. This also means that the industries look in the direction of what the several coating approaches have to offer. This paper will examine the possibilities in three different processes: atmospheric plasma spraying (APS), high velocity oxy-fuel (HVOF) spraying and laser remelt (laser fusing). Cobalt and nickel based coating materials were employed. To some extent, tungsten carbides, chromium oxides and one sealing method will be conducted for comparison. The processes and produced coatings were analyzed using a standard electrochemical setup to characterize the specific corrosion properties of the coatings for direct comparison. Furthermore, the coatings were analyzed using light optical (LOM) and scanning electron microscopy (SEM) to interpret and support the electrochemical measurements.