Surface sealing of electron beam physical vapor deposited thermal barrier coatings by high-intensity pulsed ion beam

Abstract

A surface sealing technology by employing high-intensity pulsed ion beam (HIPIB) technique is developed for electron beam physical vapor deposited (EB-PVD) thermal barrier coatings (TBCs) to further improve the high temperature performance. The HIPIB irradiation can deliver a high-density energy up to 100J∕cm2 into the shallow ion range of about 0.1–10μm within a short pulse width of less than 1μs, by which a micrometer-thick bridging layer was achieved on the gap between columnar grains of EB-PVD TBCs under a single pulse of 4.5J∕cm2. The thin bridging layer provided atmosphere shielding for the TBCs along with matching strain tolerance of the columnar top coat during thermal cycling. Cyclic oxidation tests at 1050°C demonstrated that weight gain of the sealed TBC samples is decreased by about 60% from 0.8mg∕cm2 of the as-deposited ones.