Effects of initial oxidation on β phase depletion and oxidation of CoNiCrAlY bond coatings fabricated by warm spray and HVOF processes

► A modified HVOF process called “Warm Spray” was used to deposit CoNiCrAlY alloy. ► This alloy is important as a bond coat (BC) material for thermal barrier coatings. ► Comparison was made between bond coatings by HVOF and WS. ► Rougher and less oxidized BCs were deposited by the WS process. ► A simple diffusion model showed that initial oxidation determines service life time.