The Influence of Processing on Crack Formation,Microstructure,Density and Hardness of Sol-Gel Derived Zirconia Films

摘要

Sol-gel zirconia films were deposited onto stainless steel and glass substrates by dip-coating.The correlation between the withdrawal speed,the sol composition and the resulting film thickness was studied.If a critical film thickness is exceeded,crack formation occurs.Cracking is one of the major drawbacks of the sol-gel deposition method because of the limitation of the maximum film thickness achievable without crack formation via single step deposition.The correlation between sol composition and crack formation was examined.Especially the role of polyethylene glycol (PEG)-an organic additive to reduce crack formation-was studied.Multi-layer coatings were deposited to characterize film density and hardness as a function of the heat treatment temperature from 400 to 800 deg C.The film density was found to be between 4 g cm~(-3) to 5.5 g cm~(-3) and the film hardness was in the range of 2.8 to 6.0 GPa,with a steep increase observed between 450 to 600 deg C.