Investigation on the Wettability between Nb-Al Alloy and Porous Al2O3 Ceramics Prepared by Freeze Casting

This paper adopted freeze casting method to prepare porous Al2O3 ceramic bodies with interconnected pore channels as a preform. The preform was pressureless infiltrated with Nb-Al binary alloy by using electromagnetic induction furnace. The results indicated that the Nb-Al melt solidified as a sphere-like body under the surface tension driving. It was difficult to obtain Nb-Al binary alloy matrix Al2O3 ceramic composites. However, the wettability between Nb-Al melt and porous Al2O3 ceramic bodies was improved obviously while the Ti and Cr alloying elements were added into Nb-Al binary alloy. Also, the resultant Nb-35Ti-20Al-10Cr melt was tilled into the interconnected pore channels existed in the Al2O3 preform by pressureless infiltration.