Fracture strength of ion-exchange silicate-containing dental glass ceramics
| Autor: | David J. Green, Tzer‐Shin Sheu |
|---|---|
| Rok vydání: | 2007 |
| Předmět: |
Aqueous solution
Materials science Sodium oxide Weibull modulus Mechanical Engineering Mineralogy Potassium oxide chemistry.chemical_compound chemistry Flexural strength Mechanics of Materials Phase (matter) visual_art Aluminium oxide visual_art.visual_art_medium General Materials Science Ceramic Composite material |
| Zdroj: | Journal of Materials Science. 42:2064-2069 |
| ISSN: | 1573-4803 0022-2461 |
| Popis: | Dental glass ceramics with the composition of (0.2K, 0.8Na)2O–xAl2O3–ySiO2 (x = 0.4–0.8, y = 4–6) were studied for their mechanical properties. Different ion-exchange practices were used to modify the sub-surface concentration distributions of K+, Na+, and H+ of these glass ceramics. Specimens were heat-treated in molten KNO3, and NaNO3 + KNO3 salt baths at 350–450 °C for the ion exchanges of K+ and Na+, or in the 4% acetic aqueous solution at 85 °C for a hydration treatment. Some glass ceramics contained a feldspar crystalline phase, which was not affected by different ion-exchange practices. Specimens with a single ion-exchange process or with the hydration treatment had higher flexural strength than those without either of these two treatments. For double ion-exchange specimens, the flexural strength increased with decreasing ion-exchange temperature. The double ion-exchange specimens had flexural strength up to 280 MPa, which was slightly lower than that of the single ion-exchange specimens, but much higher than that of the as-annealed specimens. However, the Weibull modulus of these double ion-exchange specimens was 5–8 because of the presence of large defects. For further increasing mechanical reliability, silicate-containing dental glass ceramics were required to have appropriate flaw controls and ion-exchange processes. |
| Databáze: | OpenAIRE |
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