At the 12th PIB Practical Forum for Industrial Coating, experts from the Quality Association for Industrial Coating (QIB) presented the initial results of the extensive QIB blasting project. This was dedicated to the question of how blasting abrasives influence the adhesive strength and corrosion resistance of coatings.
13 different blasting media tested
Blasting is a proven method for pretreating surfaces, but unfortunately blasted surfaces do not always reach their full potential. This often leads to premature failure of the corrosion protection or other defects in the coating. In this project, 13 different blasting media - including angular and round, metallic and mineral materials - were tested to determine which would best provide the desired bond strength and corrosion resistance. Over 100 steel plates were blasted according to strict specifications and then coated with a 1-layer powder coating system.
Initial findings and results:
The series of tests showed that both angular abrasives and round abrasives achieved remarkably good results. All samples treated with the optimum abrasive operating mixture survived the 480-hour corrosion test without any significant defects. The correct abrasive operating mixture is particularly important. It must be neither too coarse nor too fine, neither dusty nor oily in order to achieve optimum surface roughness and cleanliness. The right abrasive - matched to the corrosion protection system - enables the full potential of the blasting process to be exploited. "Vulkan Inox's own stainless steel blasting media, Chronital and Grittal, have also proven particularly effective," says Christian Hoffmann, Head of Sales at Vulkan Inox and member of the QIB blasting project.