Epitaxial MCrAlY coating on a Ni-base superalloy produced by electrospark deposition

A novel electrospark deposition technique has been successfully developed to deposit epitaxially MCrAlY coating onto a directionally solidified nickel base superalloy. The coating is featured by cellular directionally solidified microstructure with primary γ phase. Its formation mechanism may be attributed to the facts that the alloy solidifies primarily with γ phase and solidification conditions of the tiny thin melt close to the limit of constitutional undercooling under the electrospark treatment condition.