Influence of Process Parameter on Grit Blasting as a Pretreatment Process for Thermal Spraying

In thermal spraying uncoated substrates usually require roughening. As the most common roughening method, grit blasting increases the surface area and produces undercuts, which facilitate mechanical interlocking and thus promote the bonding between the substrate and coating. The effects of grit blasting parameters, i.e. the particle size, the blasting angle, the stand-off distance and the pressure, on the resulting surface topography are investigated. Furthermore the efficiency and wear behavior of the blasting media are analyzed. Influences of three different blasting media, corundum, alumina zirconia and steel shot, on the surface roughening are compared.