Rotating-Arm Reaction Ball Milling for Mechanical Alloying and Solid State Amorphication of Ceramics

Abstract

Far from equilibrium rotating-arm reaction ball milling is developed for the mechanical alloying and solid state amorphization of ceramic materials. This processing provides peripheral equipments for the measurements of the temperature inside the PSZ tank and the torque applied to PSZ agitating-arms for the efficient and high quality production of amorphous (a) ceramic powders. We find that the mechanical alloying of powder mixture, PSZ-20mass%Al₂O₃ can produce the solid state amorphization in the multilayer (ml), according to a single reaction of ml-(PSZ/20mass%α-Al₂O₃)→a-(3mol%Y₂O₃-ZrO₂)₈₀(Al₂O₃)₂₀. The reaction milling method can be used to determine the starting time (t_s) of the exothermic amorphization at the plateau attrition temperature. The analysis of Johnson-Mehl-Avrami equation with X=1-exp{-k(t-t_s)ⁿ} shows that the isothermal amorphization obeys an exponential growth law with n=0.5 by using volume fractions (X), as obtained by X-ray diffraction method, of amorphous (3mol%Y₂O₃-ZrO₂)₈₀(Al₂O₃)₂₀. Furthermore, our dry attrition milling realizes free from the contamination of Iron incorporated in the amorphous ZrO₂-20mol%Al₂O₃ particle, when compared with the previous result.