High Velocity Oxygen Fuel (HVOF) is a thermal spray coating which is used to improve the strength and durability of a component’s surface. The process involves fuel and oxygen continually igniting and combusting in a combustion chamber, in order to produce a hot gas which is then injected with a powder feed stock. The hot gas and powder are released as a jet stream and directed towards a component, producing a powder coating which forms a hard-wearing surface.
Electroplating Hard Chrome (EHC) or Hard Chromium Coating Electroplating has been widely used as a process which provides components with high hardness, corrosion resistance and low friction. During the electroplating process, a chromium solution is deposited onto a metal component, creating a thin yet hard layer.
In recent years, High Velocity Oxygen Fuel has been increasingly employed as a replacement to Electroplating Hard Chrome across various engineering industries, including aerospace, marine transport, oil and gas. After concerns were raised regarding the health and safety and environmental impacts of EHC, associations began searching for a replacement coating solution to become a standardised process amongst major engineering companies.
So, what are the benefits of HVOF in comparison with EHC?
HVOF has been proven to have increased overall wear resistance. When HVOF and EHC were tested for sliding wear resistance, HVOF was reported to have 200x less material volumetric loss than EHC. Additionally, HVOF was revealed to have increased abrasive wear resistance with nearly 7x less volumetric loss than that of EHC, making HVOF a conclusively more wear resistant coating solution.
Following a three year long corrosion assessment, HVOF thermal spray coatings were reported to have performed significantly better than EHC coatings. Completed as atmospheric salt-water-beech corrosion experiments, each coating was applied to steel and rigorously tested, revealing HVOF to be the more corrosion resistant coating.
In order to determine the impact resistance of both EHC and HVOF, steel specimens were coated in each solution before gravel impingement and ball impact tests were conducted. During these trials, the extent of surface damage and cracking was significantly reduced on the HVOF coated components compared to the EHC specimens.
During extensive testing across various studies, specimens coated in EHC suffered a substantial loss in fatigue strength, whereas HVOF coated components revealed an increased fatigue performance.
To determine the cost effectiveness of both HVOF and EHC, a detailed cost and benefit analysis was conducted using the Environmental Cost Accounting Methodology. The results showed huge annual cost avoidances and high 15-year net present values, in favour of HVOF.
Time and time again, High Velocity Oxygen Fuel has outperformed Hard Chromium Coating Electroplating to become the superior coating solution for engineered components. Which is why, at EP Coatings, we recommend and supply HVOF as a high quality, performance effective and cost efficient coating solution for all major engineering companies.