ABSTRACT
Since ZrO2 is a nonplastic material, slip casting of objects using this technique is difficult. The objective of the present work was to develop a slip casting technique for ZrO2 using water plus a deflocculant/binder that gives a high degree of deflocculation, slow casting rate and adequate green strength.
Y2O3-stabilized ZrO2 (mean particle size https://www.w3.org/1998/Math/MathML"> d = 19.3 μm https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781003421290/07e4de97-c68f-4ca1-95b4-28d8b410031d/content/eq268.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/> ) from ICI Advanced Ceramics was ball milled for 90 hours to produce a powder of average particle size https://www.w3.org/1998/Math/MathML"> d = 1.64 μm https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781003421290/07e4de97-c68f-4ca1-95b4-28d8b410031d/content/eq269.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/> . Slips containing 65 wt% yttria-stabilized zirconia (Y-TZP) and 35 wt% demineralised water were prepared with 0.05-0.93 wt% sodium carboxymethylcellulose (Na-CMC) added as a deflocculant/binder. Viscosity, thixotropy, casting rate, cast density and diametral shrinkage tests were performed as a function of Na-CMC addition.
Concurrent optimisation of the viscosity, thixotropy, casting rate, cast density and diametral shrinkage was obtained for ~ 0.25 wt% Na-CMC addition. This produced a body with low, yet sufficient green strength for handling as a result of the binding power of the Na-CMC molecules.
