PHYSICOCHEMICAL PROCESSES ACCOMPANYING THERMAL-GRADIENT PROCESSING OFBI2SR2CACU2OX CERAMICS

The physicochemical processes accompanying optical zone melting of Bi2 Sr2CaCu2Ox ceramics were studied by electron-probe x-ray microanalysis and x-ray diffraction. The results show that eutectic and peritectic reactions between the major and additional phases give rise to the for mation of a liquid phase in pores of the material. The liquid is respo nsible for the adverse processes observed in the premelting region. Th e role of contact melting is insignificant. The adverse effects can be reduced by decreasing porosity and enhancing homogeneity of the mater ial. The obtained data allow the requirements on the microstructure of ceramics for zone melting to be stated.