Plasma-aided manufacturing of ceramics and composite materials

Abstract

Owing to the recent availability of plasma generating devices and their reliable performance, the applications of plasma technology in materials processing is rapidly increasing. In this paper, therefore, the progress of plasma technology in materials processing has been critically examined. Also, the experimental results of the authors' investigation of the sintering kinetics of A1₂0₃ and PSZ, with and without Al₂0₃, in the plasma environment have been presented and discussed. Alumina and partially stabilized Zr0₂, with and without A1₂0₃, have been sintered in a radio frequency induction coupled plasma system. The translation speed of the specimens through the plasma, power level, sintering additives and pressure into the reaction tube were investigated as the experimental variables to elucidate the sintering mechanism (s). Both A1₂0₃ and partially stabilized Y₂0₃-+-Zr0₂ rods have been sintered with final densities greater than 99.7% at a very high densification rate. The grain sizes of the sintered specimens were smaller by a factor of two than the same materials sintered in a non-plasma environment. Specimen temperatures were found to be a function of plasma-supporting gas pressure, applied power and translation speed (TS) of the specimens. In the case of partially stabilized Zr0₂ in Ar plasma, temperatures increased with the increase in the TS of the specimen up to 6cm/min.