An Example of the Decision Making Process for the Evaluation of Tungsten Carbide Thermal Spray Coatings as Replacements for Electrodeposited Chrome Plating

摘要

The process for electrodepositing chrome generates environmental disposal problems and long repair turn-around times for chrome plated parts. This has motivated the aerospace/airline industry to investigate the applicability of tungsten carbide (WC) thermal spray coatings for chrome replacement. Thermal spray coatings of tungsten carbide are currently being used in the industry on components that were chrome plated in the past. These coatings are used to reduce wear damage of lightweight metals, such as aluminum and titanium, and are also used for corrosion protection of high-strength steel. Tungsten carbide cobalt (WC-Co) and tungsten carbide cobalt chrome (WC-Co-Cr) thermal spray coatings applied by the High Velocity Oxy-Fuel (HVOF) process are considered the primary replacement coatings. The performance of these thermal spray coatings must be evaluated prior to acceptance as a suitable replacement. This report describes the decision making process followed to establish the acceptability of WC thermal spray coatings for several applications. A description of both the laboratory testing phase and the in-service evaluation phase is given. Examples of test results, comparing chrome plating versus WC thermal spray coatings, are presented.