Mc. Wang et al., PREPARATION OF NEPHELINE GLASS-CERAMICS AND THEIR APPLICATION AS DENTAL PORCELAIN, Materials chemistry and physics, 37(4), 1994, pp. 370-375
The batch of starting glass was prepared from analytical-grade reagent
s. Crystallization of the nepheline glass system was investigated usin
g differential thermal analysis, X-ray diffraction, transmission and s
canning electron microscopy. The major crystalline phase was found to
be nepheline, Na2O.Al2O3.2SiO2. The Vickers microhardness of these mat
erials is 640-660 MPa, and the thermal expansion coefficients are 12.1
-16.6 x 10(-6) K-1 from 298 to 773 K. The nepheline glass-ceramic powd
ers were coated on a Ni-Cr alloy pattern. It was found that the failur
es of the composites usually occurred at the interface between the all
oy and opaque layer.