Optimization of Sintering Process of Alumina Ceramics Using Response Surface Methodology

In this work, alumina (Al2O3) ceramics were prepared using an environmentally friendly slip casting method. To this end, highly concentrated (70 wt.%) aqueous suspensions of alumina (Al2O3) were prepared with different amounts of the ammonium salt of a polycarboxylic acid, Dolapix CE 64, as an electrosteric dispersant. The stability of highly concentrated Al2O3 aqueous suspensions was monitored by viscosity measurements. Green bodies (ceramics before sintering) were obtained by pouring the stable Al2O3 aqueous suspensions into dry porous plaster molds. The obtained Al2O3 ceramic green bodies were sintered in the electric furnace. Analysis of the effect of three sintering parameters (sintering temperature, heating rate and holding time) on the density of alumina ceramics was performed using the response surface methodology (RSM), based on experimental data obtained according to Box-Behnken experimental design, using the software Design-Expert. From the statistical analysis, linear and nonlinear models with added first-order interaction were developed for prediction and optimization of density-dependent variables: sintering temperature, heating rate and holding time.

Automated summary

In this study, alumina ceramics were prepared using an environmentally friendly slip casting method by preparing highly concentrated alumina aqueous suspensions with the addition of the ammonium salt of a polycarboxylic acid as a dispersant. The stability of the suspensions was monitored by viscosity measurements, and green bodies were obtained by pouring the stable suspensions into plaster molds before sintering in an electric furnace. Analysis of sintering parameters on density was performed using response surface methodology and statistical modeling for prediction and optimization of density-dependent variables.