Hard chrome plating is a coating process which deposits chromium 2-250µm in thickness onto a substrate. Chrome plating is used for wear and corrosion resistance, as well as providing a low-friction surface. Unfortunately, the chroming process presents a significant environmental and health concern, as the hexavalent chromium (Cr6+) used is highly toxic, carcinogenic and requires expensive disposal via specialised waste contractors. Chroming is also a ‘one-size-fits-all’ approach, and service life will depend heavily on the operating environment of the component.
HVOF (High Velocity Oxy-Fuel) is an excellent alternative to chrome – it is a thermal spray process which mechanically bonds metal coatings to a substrate. HVOF offers far superior abrasion wear and corrosion resistance, the coatings result in negligible fatigue on the substrate and the coatings can be tailored to suit the operating environment and budget. This includes specific coatings for acidic, alkaline, saline and corrosive environments, or situations where components will be subjected to high heat, impact or abrasion damage. HVOF can also be built up to more than 6mm in thickness, providing greater refurbishment potential and significantly extending the life cycle of components. This results in less downtime and a more cost-effective, long-term repair solution.
Two 793 front suspension rods from the same machine (same operating environment, same operating hours) – the rod on the left was coated with hard chrome, the rod on the right with HVOF. Whilst the chromed rod required a full re-coat, the HVOF rod required only a quick polish to restore it to specification and full working order
