Which is better, HVOF or HVAF

       

Due to the erosion caused by particles and
gas, hydropower plants using silt water for power generation will suffer
serious metal loss. Many factories use oxygen combustion supersonic flame
spraying process (HVOF) to produce coatings, so as to improve the service life
of equipment.

There are also factories using air
combustion supersonic flame spraying technology(HVAF). This technology can
provide higher particle velocity and lower spraying temperature, so it can
obtain more compact non oxidation coating.

Many people will ask whether HVOF or HVAF
is better for combustion? In the condition where HVOF particle velocity reached
740m / s and HVAF particle velocity reached 895m / s and 1010m / s, we used
WC10Co4Cr. Then we compared the mechanical properties of the two sprayed
coatings, including porosity, hardness, indentation toughness and gas corrosion
resistance. The surface damage of the coating was analyzed by scanning electron
microscope (SEM). The weight loss of the eroded coating surface was measured at
different time periods. The uniformity of bond strength of each coating was
qualitatively detected by measuring the scratch depth of cross section. The
results show that HVAF coating has low porosity, high hardness and excellent
gas corrosion resistance. The phenomenon of carbide particles peeling and
falling off can be observed in HVOF coating, but this phenomenon is relatively
less in the damaged area of HVAF coating. For WC10Co4Cr or high velocity
oxyfuel fuel spraying powder, search wococarbide for more information.