Comparison between Slip Casting and Cold Isostatic Pressing for the Fabrication of Nanostructured Zirconia

Abstract

Consolidation of ceramic parts may be achieved by several techniques, including the slip casting and cold isostatic pressing (CIP) methods. In the present work, the performances of the two methods are compared in the fabrication of nanostructured zirconia compacts for dental crown applications. First, a zirconia suspension suitable for slip casting was prepared. The rheological properties of the zirconia suspension were optimized by adding a dispersant agent and controlling the pH. Zirconia slurries were then slip-cast into a pellet. Second, another group of zirconia pellets were fabricated using uniaxial pressing and were then cold-isostatically pressed. Both slip-cast and CIP samples were sintered at 1300 °C with a soaking time of 2 hrs. The mechanical properties of both samples were compared. The samples prepared by slip casting were denser compared with those prepared via CIP. Slip casting technique produced samples with 98.8% of the theoretical density, which resulted in the high Vickers hardness (11.4 GPa) of the slip-cast samples. Morphological studies revealed that the microstructures of the slip cast-sample were more homogeneous and contain no porosity. The formation of such a structure is due to the enhancement of the particle packing efficiency by slip casting as well as to the removal of larger agglomerates by colloidal processing prior to casting. As a consolidation stage, slip casting appears to be more suitable than the CIP technique in preparing reliable nanostructural ceramic parts.

Influences of solid content of slurry on the microstructure of CaO crucible prepared by slip casting

“…It was demonstrated by the experiments of Lange and Roosen that colloidal processing method has obvious advantages over dry pressing with the potential for particles movement and rearrangement in the liquid. [11][12][13][14][15] Yousefian et al 16 prepared Zirconia-doped yttria transparent ceramics by slip casting method, and several processing parameters including solid load, the pH value of slurries, amounts of Dolapix CE 64 as a dispersant, citric acid, and de-agglomeration time were optimized. Tari et al 17 studied the effect of solid content on the shrinkage of the magnesium aluminate spinel (MgAl 2 O 4 ) samples, which reflected that the shrinkage of sample decreased while the solid content increased.…”

“…It was demonstrated by the experiments of Lange and Roosen that colloidal processing method has obvious advantages over dry pressing with the potential for particles movement and rearrangement in the liquid 11–15 . Yousefian et al 16 .…”

Influence of Thermal Expansion on the Bond Strength of Nanozirconia and Veneering Ceramics

“…However, nanoparticles are susceptible to agglomeration, which results in inferior-quality blocks [9,10]. By utilizing a special colloidal processing technique, zirconia powder with good particle homogeneity and a packing density of almost 100 wt% can be developed [11]. The combination of wet-processing and slip-casting techniques allows the fabrication of machinable zirconia blocks with good mechanical and aesthetic properties [12][13][14][15].…”