A statistical analysis of the effect of a mixture component on the rheology of alumina feedstocks

A statistical analysis based on the McLean-Anderson design method was carried out in studying the influence of each formulation component on the flow properties of alumina feedstocks. The formulations were composed of alumina powder (AL), polypropylene resin (PP), paraffin wax (PW), and stearic acid (SA). Fourteen different formulations were designed and their viscosities were measured using a capillary viscometer. The corresponding rheological parameters, i.e., fluidity, pseudoplasticity, and flow energy (ΔE) were evaluated and the effects of each ingredient in the mixture on them were analyzed. The studied ranges of AL, PP, PW, and SA were 87 to 89, 5 to 9.25, 3 to 7.25, and 0.75 to 1.5 wt pct, respectively. The results indicated that the lower alumina content or higher binder content would improve the fluidity of feedstocks. The order of increase in fluidity is SA > PW > PP. An increase of either AL or SA or a decrease of either PP or PW would cause less shear thinning in the resulting mixtures. Polypropylene resin is more effective than PW in enhancing pseudoplasticity. Finally, ΔE of feedstocks first decreases, reaches a minimum value at AL of about 87.7 wt pct, and then increases with powder loading. Increasing SA or decreasing either PP or PW would make ΔE smaller.