Defects in the in situ synthesized TiB2/Fe composite coatings during PTA process

The in situ synthesized TiB2/Fe composite coatings were deposited by the plasma transferred-arc (PTA) powder surfacing process. The macro and micro defects in the TiB2/Fe composite coatings were investigated in this paper. It is found that heat input plays an important role in macro defects in the coatings. Only when the energy density and total heat input are appropriate will nice forming with few macro defects be obtained. As micro defects in the coatings, slag inclusions (C, Al2O3) and cracks often appear together. And it is found that slag inclusions and cracks tend to appear with a low dilution rate of the coatings, and their tendency decreases as the dilution rate increases.

► The macro and micro defects are sensitive to the surfacing process conditions. ► The coatings' surface forming depends on both energy density and total energy input. ► Slag inclusions and cracks often appear together. ► The tendency of slag inclusions and cracks decreases as the dilution rate increases.