EFFECT OF BALL MILLING ON FORMATION OF ZnAl₂O₄ BY REDUCTION REACTION OF ZnO AND Al POWDER MIXTURE

Abstract

It is well known that thermal energy generated during high energy milling / alloying can facilitate the reduction reaction, leading to formation of com-pounds and oxide reinforced composites. Solid state reduction reaction by the mixture of high purity fine zinc oxide and metallic Al powders is investigated. The ZnO powders are added to aluminum powder in ball milled and milled conditions, and then attrition milled for different times. The former is called double ball milled, and the latter is called single ball milled since it is only attrition milled. The results are further studied and verified by XRD, SEM, DTA and particle size analyzer. The complete reduction of ZnO to Zn is almost obtained in powders double ball milled for 10 h, which is converted to ZnAl₂O₄ when vacuum annealed. In the case of single ball milled powder, reduction of ZnO is partially done and no ZnAl₂O₄ phase forms after annealing.