Thu, 15 August, 2024
TWI has been using its new, state-of-the-art thermal spray coating process, high velocity air fuel spraying (HVAF), for the application of dense alloy and cermet coatings in projects for Industrial Members working in a wide range of sectors.
As with high velocity oxygen fuel spraying (HVOF), a key advantage of HVAF spraying is the ability to produce high quality coatings from carbide cermet materials and metallic powders to protect parts against abrasion, erosion and corrosion.
Benefits of HVAF
As well as delivering high quality coatings, HVAF offers reduced OpEx due to the high spray rates, reduced surface preparation and reduced post-coating finishing operations relative to traditional coating systems. Additionally, the HVAF process has the capability to produce coatings on internal diameters.
These benefits allow the latest HVAF (and HVOF) technologies to act as an alternative to hard chrome plating and other coatings for REACH-compliance, repair and reclamation, and the application of critical and strategic materials via the deposition of denser, higher quality coatings at a lower cost.
TWI Research
TWI has already evaluated HAVF technology for the application of nickel alloys, stainless steel and cermet coatings such as WC-CoCr and Cr3C2-NiCr for industries including construction and engineering, nuclear, metal recycling and geothermal. The research showed that the coatings exhibit dense microstructures with excellent performance when compared to both HVOF and cold spray coatings.
Work is currently concluding on a Joint Industry Project (JIP) to assess the performance of HVOF, HVAF and extreme high speed laser application (EHLA) coatings. However, early findings show that HVAF coatings have performed exceptionally well in tests, including during salt spray testing.
Next Steps
Our research into HVAF is continuing with the launch of a new Joint Industry Project to evaluate the mechanical performance of advanced HVOF and HVAF coatings as hard chrome replacement alternatives.
Industrial Members are invited to join the project, which will assess 4-point bending, fatigue and the wear performance of these advanced coatings for industrial service.
To find out more about the technology or the soon-to-launch JIP, please contact us at: surfacing@twi.co.uk