Open AccessMicrostructural Characterization and Microhardness of Leucite Glass-Ceramics Synthesized from Sarawak Sand Reserves.
Author(s) -
Jasmina Qamaruzzaman,
Muhammad Hussain Ismail,
Andanastuti Muchtar,
Malek Selamat,
Rohaya Ahmad
Publication year - 2020
Publication title -
iop conference series. materials science and engineering
Language(s) - English
Resource type - Journals
eISSN - 1757-899X
pISSN - 1757-8981
DOI - 10.1088/1757-899x/834/1/012044
Subject(s) - leucite , materials science , indentation hardness , crystallization , scanning electron microscope , sintering , mineralogy , ceramic , composite material , microstructure , chemical engineering , geology , engineering
The purpose of this study was to evaluate the effect of varying the sintering temperature and holding time on the crystallization and microhardness of the SiO 2 – Al 2 O 3 –K 2 O glass system using SiO 2 from Sarawak sand reserves. A starting glass composition of SiO 2 (from Sarawak sand), Al 2 O 3 , K 2 O, Na 2 O, CaO, LiO and TiO 2 was prepared by conventional melt quenching technique followed by ball milling. The glass powder was pressed under pressure into disk-shaped compacts with 2 mm thicknesses and 14 mm diameters. The samples were then subjected to differing heat treatment schedules of 750°C, 800°C and 850°C with 1, 3 and 6 hours holding times. They were characterized by X-ray Diffraction (XRD), Scanning electron microscopy (SEM) and Vickers microhardness. XRD showed the crystallization of tetragonal leucite with minor secondary sanidine phases. SEM showed the formation irregular shaped and non-uniformly dispersed crystals. The hardness values showed an increasing trend with longer holding time at temperatures of 750°C and 800°C. This pattern was inversed for sintering temperature 850°C. In conclusion, sintering temperatures and holding time combinations influenced the crystallization and microhardness values of leucite glass ceramics produced from Sarawak sand silica.