M. Pena et al., PHASE-RELATIONS OF A SILICIDE SILICA REACTION COUPLE AT 2273 K/, Metallurgical and materials transactions. B, Process metallurgy and materials processing science, 27(2), 1996, pp. 271-276
Citations number
16
Categorie Soggetti
Material Science","Metallurgy & Metallurigical Engineering
The phase relations of a zirconium silicide/silica reaction couple hav
e been investigated at 2273 K in air. After annealing times from 4 to
49 hours, the reaction couples, created by encapsulating zirconium dis
ilicide in a quartz ampule, developed an interdiffusion zone and an in
ner core consisting of solidified zirconium silicide. The interdiffusi
on zone consisted of a silica layer, zirconia precipitates, and prior
liquid silicide globules dispersed in prior liquid silica. Zirconia pr
ecipitates formed from the oxidation of the silicide melt between the
protective silica layer and the two liquid regions of silicide and sil
ica, as a result of oxygen diffusion. At 2273 K, the inner core consis
ted of liquid zirconium silicide (ZrSi)(l), although the microstructur
e analysis indicated formation of proeutectic ZrSi2 and a eutectic mic
rostructure of ZrSi2 and Si upon solidification. A constant oxygen pot
ential developed within the interdiffusion zone and protected the sili
cide from oxidation even after 49 hours at temperature.