| Physico‑mechanical behaviour of alkali and alkaline earth metal‑containing mica glass–ceramics: a comparative evaluation |
| Amit Mallik |
| Department of Chemistry, Acharya Jagadish Chandra Bose College, 1/1B, A.J.C.Bose Road, Kolkata 700020, India |
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Received: February 14, 2020; Revised: April 24, 2020 Accepted: April 25, 2020. Published online: September 30, 2020. |
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| ABSTRACT |
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Mica glass–ceramics are known for their superior mechanical strength, fracture toughness and machinability. Crystallization, microstructure and mechanical behaviour of alkali and alkaline earth metal-containing mica glasses based on K2O/SrO/BaO·4MgO·Al2O3·6SiO2·2MgF2 composition were investigated by differential thermal analysis, X-ray diffraction, scanning electron microscopy and microhardness indenter. A distinct crystallization exotherm was observed in the differential thermal analysis curve.The crystallization peak corresponded to the formation of K-fluorphlogopite for K-glass, Sr-fluorphlogopite for Sr-glass, and Ba-fluorphlogopite for Ba-glass. XRD results revealed that the above-mentioned formations were the major phases, while alpha hexacelsian, enstatite, and mullite were the minor phases in K-, Sr-, and Ba-glass–ceramics. SEM results indicated that the “house of cards” microstructure appeared in Sr-glass–ceramics at lower crystallization temperature than in the K- and Ba-glass–ceramics. The physico-mechanical properties of Ba- and Sr-glass–ceramics were compared with K-glass ceramics, and it was found that Ba-glass–ceramics possessed superior crystallization, microstructure and mechanical strength than the other two glass ceramics. |
| Key words:
Microstructure · Hardness · Mica glass ceramics · Fracture toughness · Machinability · Alkaline earth metal |
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