Pressure infiltration of molten aluminum for densification of environmental barrier coatings

Abstract Environmental barrier coatings (EBCs) effectively protect the ceramic matrix composites (CMCs) from harsh engine environments, especially steam and molten salts. However, open pores inevitably formed during deposition process provide transport channels for oxidants corrosives, lead to premature failure of EBCs. This research work proposed a method pressure infiltration densification which blocked these in coatings. These results showed that it was difficult aluminum infiltrate spontaneously, but with increase external gas internal vacuum simultaneously, obviously moved forward, finally stopped infiltrating at depth specific geometry. Based on wrinkled zigzag pore model, mathematical relationship between critical intrinsic geometry established. The confirmed this relationship, indicating given coating, dense thick film can be obtained by adjusting pressures drive melt infiltration.