Slip Casting of Titanium Powder for Dental Prosthetic Appliances

Abstract

The feasibility of using slip casting of titanium powder as a method for manufacturing dental prosthetic appliances was examined. Slips with water-powder (W/P) ratios, 0.318, 0.354 and 0.391, and with minimum viscosities were cast in plaster molds. Castings were sintered in an argon atmosphere at 1373, 1473 and 1573 K for 3.6, 7.2 and 10.8 ks, respectively. Green densities and strengths of castings were 2.20 kg/m 3 and 2.31-3.82 MPa, respectively. Linear shrinkages and relative densities of sintered castings varied from 17.6 to 20.8% and 0.82 to 0.97 of the theoretical density of titanium, respectively. Tensile strengths and Vickars hardness of the sintered castings were 199.5-315.4 MPa and 233.0-247.7, respectively. There was almost no elongation. Decreasing porosity and crystal grain growth were found in the microstructures of sintered castings and rod-like precipitates of TiC with -titanium were also observed. Concentrations of carbon and oxygen in the microstructures of sintered castings were higher than those in wrought titanium. Fractured surfaces showed ridge patterns typical of brittle fracture. Further modification of the sintering atmosphere and the additives for the slip is needed to improve the microstructure of slip-cast sintered titanium.

Synthesis and Mechanical Characterization of Al Casting Produced by Slip Casting and Pressure Less Sintering

“…When fine powder is mixed in water to produce suspension, attractive forces are developed between water molecules and suspended particles in most of the cases which may cause sedimentation. The stability, castability and the green density of the slurry after drying are very important properties and controlled by the shape of particles, stabilizing additives, viscosity and the pH of the slip [18,21]. A stable slip can be made with liquids and dissolved surface-active ions which are adsorbed on the particle…”

“…surface. Sedimentation and agglomeration is prohibited by repulsion between like charge particles [21]. Al powder was used in the current investigation and a thin oxide layer appeared on particles surface which formed surface OH-groups in suspension or slip.…”

Porous shape-memory NiTi-Nb with microchannel arrays

“…Slip casting [28] has been used to create Ti and NiTi foams with sodium alginate as a binder, by partial sintering of Ti powders [29] and by SHS of elemental Ni and Ti powders [30], respectively. In another study, the slurry to make Ti foams was optimized using a PVA binder [31].…”

The effects of organic template and thickening agent on structure and mechanical properties of titanium foam fabricated by replica impregnation method

“…Ohkawa et al [6] used sodium alginate as a binder for slip casting of dental implants. However, the resultant sintered titanium products contained precipitates of TiC, which limited elongation.…”