Microstructure of a high strength alumina glass composite

Abstract

The morphology and microstructure of an Al2O3 glass composite (trade name In-Ceram, Vita Zahnfabrik) were studied using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The composite was produced by infiltration of a lanthanum-based glass throughout a porous Al2O3 body. This alumina body was formed by three classes of particles differing in size and shape: faceted particles typically ≤4 μm in diameter, platelets of average diameter 8 μm, 1.5 μm thickness, and small spheres 0.4 μm in diameter. The outstanding strength properties of the composite (600 MPa, ball-on-ring test) are a result of the high wetting capability of the glass phase on the Al2O3 surface. In addition, plastic strain relaxation in the faceted particles by dislocation formation compensates partially for residual stresses and impedes crack formation at the glass/Al2O3 interface.

Subcritical crack growth behavior of Al2O3‐glass dental composites

“…In-Ceram alumina-glass composites also have ϳ5 vol.% porosity and similar defect sizes, as revealed by the present study and other investigations. 6,7 the alumina-glass composite employed in this study has a similar microstructure and a comparable fracture strength and toughness as compared with In-Ceram alumina-glass composites. Figure 2 shows the dynamic fatigue data for the aluminaglass composite in air.…”

The influence of alumina abrasion and cement lute on the strength of a porcelain laminate veneering material

“…There was also no increase in the number of two (and concomitant decrease in three) fragment fractures recorded when specimens were stored in water for 24 h (compared with specimens stored in a desiccator) suggesting that immersion in water did not result in any significant corrosive effects on the porcelain. 25 However, if it is assumed that leaching effects did occur when the alumina abraded or non-alumina abraded discs were immersed in water for 24 h SEM may not have able to detect any morphological changes if the glass dissolution rates were too low.…”

A comparison of mechanical properties of all-ceramic alumina dental crowns prepared from aqueous- and non-aqueous-based tape casting

“…The strength increases with increasing the ratio up to 0.85 and 0.825 for each system, respectively, and then does not vary significantly as the ratios are further raised. The plateau strengths of the alumina-glass dental composites are about 559 and 508 MPa for each 12,13 These values are higher than the strength of alumina polycrystals, usually prepared by sintering at temperature higher than 1600°C, which ranges from 302 to 488 MPa, depending on the grain size of alumina. 14 The variation in the fracture toughness (Fig.…”