Statistical analysis of the influence of processing parameters content on the flatness of tapes obtained by tape casting

ABSTRACT

In the present study, 5 batches of tapes made of stabilized zirconia with 8% mol of yttrium (TZ8Y) were produced by the tape casting technique, varying among them the composition of the slurry, such as solids load and the contents of binder, type I plasticizer and type II plasticizer in order to verify the influence of these parameters and the thixotropic behavior of the slurry on the occurrence of warping. After sintering, the topography of the tapes was mapped using an indicator, taking measurements across the entire surface of the tapes in a coordinate system, and, from these maps, a numerical coefficient that quantifies the flatness of the samples was defined. The influence was investigated using a bivariate statistical analysis, relating the flatness coefficient to each of the target parameters. The analysis showed a strong and significant negative correlation using the Spearman coefficient (⍴ ≅ 0,95 e p-value < 10^–3) between the type I plasticizer content and the flatness of the produced slabs, but for the other parameters analyzed the correlation could not be considered statistically significant. In addition, the results also showed that the use of a post processing on the green tapes, such as a lamination, substantially improved the flatness of the plates after sintering.

Keywords
Tape Casting; Warping; Thixotropy; Ceramics; Statistics