Effect of Zirconia‐Modified Magnesia Investment on the Casting of Pure Titanium

Abstract

Several investigations have examined magnesia-based investments for pure titanium casting. However, the thermal expansion value was insufficient at low casting temperatures and high interfacial reactivity occurred at high casting temperatures. The purpose of this investigation was to modify a magnesia-based investment by adding a heat-resistant mold material, zirconia, in different ratios to produce a more accurate titanium casting. The thermal expansion value was measured using a new precise automatic laser recording machine and pure titanium was cast using an argon casting machine. The marginal accuracy was measured using a stereomicroscope and the interfacial reactivity of the titanium was evaluated using X-ray diffraction analysis. The results indicate that adding different amounts of zirconia to a magnesia-based investment can increase its thermal expansion value and decrease the interfacial reactivity of the titanium. Maximal thermal expansion in the zirconia-modified investments significantly increased by 5-6 weight % (wt%) and peaked at 1.62% expansion. Selevest with 5 wt% zirconia had the smallest mean marginal discrepancy, 21.70 microm at 750 degrees C. Analysis of variance indicates significant differences in marginal discrepancy between zirconia-modified investments (p < 0.001). Adding zirconia can also decrease the interfacial reactivity of the titanium. The data indicated that proper amounts of zirconia (5-6 wt%) added to a magnesia-based investment can produce a more accurate and less interfacial reactive pure titanium casting.

Investigating the Effect of Shape Factor, Slurry Layers and Pouring Temperature in Precision Investment Casting

“…An analysis of variance procedure indicated that the key variables in casting superconductive ceramics are the particle size distribution and sintering temperature. Additionally, the interactions between the sintering temperature and the other process parameters also found to influence the density, porosity, and critical current density of the fired ceramics [3]. The thermal expansion value was insufficient at low casting temperatures and high interfacial reactivity occurred at high casting temperatures.…”

Investigating the surface roughness of implant prepared by combining fused deposition modeling and investment casting

“…14 Some researchers highlighted that IC has the ability to manufacture a wide range of industrial components with near net shape. 15,16 Conventional IC process starts with formation of wax pattern in precisely machined die to maintain dimensional accuracy. Patterns are attached to a riser and the resulting tree is stucco coated and kept to dry in air-controlled environment.…”

Taguchi approach for modelling of surface hardness in investment casting

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