Processing-microstructure relationships for plasma-sprayed yttrium aluminum garnet

作者：Weyant C M; Faber K T^*

来源：Surface and Coatings Technology, 2008, 202(24): 6081-6089.

DOI：10.1016/j.surfcoat.2008.07.008

• Yttrium aluminum garnet
• Thermal barrier coating
• Plasma spray
• Design of experiments
• Processing
• Amorphous coating

Plasma-sprayed yttrium aluminum garnet(YAG) has been considered as a component in a thermal barrier coating system to reduce oxidation of the bond coat by impeding oxygen diffusion through the coating. For this application, a fully crystalline, dense YAG coating would be advantageous to maximize lifetime and minimize oxygen diffusion. The effects of nine processing variables on the porosity and percent crystallinity in plasma-sprayed YAG were determined. Two powder types were investigated to compare a commercial, off-the-shelf, fused-and-crushed powder to a specially-processed, spherical plasma-spray powder. The resultant models suggest that plasma torch power and Spray distance had the largest effect on the responses. It was determined that the processing parameters that lead to a coating with low porosity produce a coating with low crystallinity and vice versa. A possible route to producing a dense, crystalline coating was explored where a dense, amorphous coating was Subsequently heat treated to produce crystalline material that retained the microstructure of the as-sprayed YAG in the bulk of the coating. However, macrocracking in the system due to thermal mismatch and crystallization stresses would need to be addressed for a viable multilayer TBC.

• 出版日期2008-8-15
• 单位西北大学