Formation mechanism of internal pores in aerosol deposition

Abstract

Full-dense Pb(Zr,Ti)O₃ (PZT) ceramics with thickness of 300 m were successfully obtained by aerosol deposition (AD) employing the starting powder subjected to an adequate pretreatment. It was found that formation of internal pores during the post-deposition firing treatment takes place in the two different mechanisms on different scales. Residual carbons contained in the as-deposited PZT ceramics are responsible for the formation of extra-large pores inducing a severe distortion to the shape of the sample. On the other hand, trapped agglomerated particles in the as-deposited PZT ceramics are responsible for the formation of intermediate pores. The relevant mechanisms are discussed with a focus on the positive/negative correlation between the pretreatment of starting powders and the formation of internal pores.