Ln. Paritskaya et al., MECHANISM AND KINETICS OF SINTERING OF NONSTOICHIOMETRIC Y-BA-CU-O POWDERS, Powder metallurgy and metal ceramics, 33(9-10), 1994, pp. 453-457
Citations number
3
Categorie Soggetti
Material Science, Ceramics","Metallurgy & Metallurigical Engineering
Using high-resolution optical and scanning electron microscopy with x-
ray microanalysis at temperatures of 880 to 920 degrees C, we studied
the kinetics and mechanism of the formation of intergranular contacts
during sintering of powder-substrate models and also studied the mecha
nism of shrinkage during sintering of Y-Ba-Cu-O compacts with a stoich
iometric composition and two nonstoichiometric compositions, Y0.95Ba2C
U3Oy and Y1.05Ba2CU3Oy. The formation and the shrinkage of powders of
different compositions were found to be described by equations of diff
erent degrees, which points to different diffusion sintering mechanism
s. Powders with stoichiometric and hyperstoichiometric compositions ar
e sintered by a volume diffusion mechanism, which is controlled by the
slowest ion, Y3+. Powders with a substoichiometric composition (Y-0.9
5) are sintered like a liquid phase, i.e., is controlled by diffusion
through liquid or solid layers where new phases with higher diffusion
coefficients are formed as a result of segregation effects.