TWI Frequently asked questions
by Suman Shrestha
Advantages of HVOF spraying over other thermal spray processes primarily relate to improved coating quality, such as:
- Higher density (lower porosity) due to greater particle impact velocities
- Better wear resistance due to harder, tougher coatings
- Higher hardness due to less degradation of carbide phases
- Improved corrosion protection due to less through porosity
- Higher strength bond to the underlying substrate and improved cohesive strength within the coating
- Lower oxide content due to less in-flight exposure time
- Retention of powder chemistry due to reduced time at temperature
- Thicker coating due to less residual stresses
- Smoother as-sprayed surface due to higher impact velocities and smaller powder sizes
