In order to prolong the service life of ZrO_(2) thermal barrier coatings,HS188 alloy was used as the substrate,and NiCrAlY powder(base layer,d_(50)=106μm)and yttria stabilized zirconia(YSZ,d_(50)=50μm)were employed ...In order to prolong the service life of ZrO_(2) thermal barrier coatings,HS188 alloy was used as the substrate,and NiCrAlY powder(base layer,d_(50)=106μm)and yttria stabilized zirconia(YSZ,d_(50)=50μm)were employed as the sprayed feeder to prepare NiCrALY+YSZ thermal barrier coatings using high-energy plasma spraying equipment with a progressive exploration method.The microstructure of the coatings was controlled by adjusting the stand-off distance(85,95,105 and 115 mm)and air-cooling manner(rear air cooling,rear air cooling+gun cooling,front air cooling,and front air cooling+gun cooling).The bonding strength of the coatings was evaluated by the drawing method.The results indicate that under the conditions of long stand-off distance and low cooling rate,it is difficult for the coatings to form a vertical crack structure due to the low instantaneous heating temperature and insufficient quenching on the sample surface.However,when the instantaneous heating temperature reaches the critical value and the air cooling rate is excessive,un-melted spray particles exist.When the stand-off distance is 85 mm and the cooling method is front air cooling,a thermal barrier ceramic coating with vertical crack morphology was obtained on HS188 alloy.Simultaneously,it has a moderate density of vertical cracks,the highest bonding strength and the best toughness.展开更多
文摘In order to prolong the service life of ZrO_(2) thermal barrier coatings,HS188 alloy was used as the substrate,and NiCrAlY powder(base layer,d_(50)=106μm)and yttria stabilized zirconia(YSZ,d_(50)=50μm)were employed as the sprayed feeder to prepare NiCrALY+YSZ thermal barrier coatings using high-energy plasma spraying equipment with a progressive exploration method.The microstructure of the coatings was controlled by adjusting the stand-off distance(85,95,105 and 115 mm)and air-cooling manner(rear air cooling,rear air cooling+gun cooling,front air cooling,and front air cooling+gun cooling).The bonding strength of the coatings was evaluated by the drawing method.The results indicate that under the conditions of long stand-off distance and low cooling rate,it is difficult for the coatings to form a vertical crack structure due to the low instantaneous heating temperature and insufficient quenching on the sample surface.However,when the instantaneous heating temperature reaches the critical value and the air cooling rate is excessive,un-melted spray particles exist.When the stand-off distance is 85 mm and the cooling method is front air cooling,a thermal barrier ceramic coating with vertical crack morphology was obtained on HS188 alloy.Simultaneously,it has a moderate density of vertical cracks,the highest bonding strength and the best toughness.
