Keywords: Melting temperature; ceramic glaze; melting time; hardness

Abstract

Production of low temperature glazes can benefit manufacturers by reducing production costs as well as improving the aesthetical value of ceramic products. A low temperature glaze was prepared by mixing 1.6 g of carboxymethyl cellulose (CMC), 20% boron oxide, 10% kaolin, 45% sodium feldspar, and 25% sodium silicate. Addition of CMC into the mixture was aimed to strengthen the bonds between particles. The mixture was stirred at 900 rpm ± 100 for 1 hour and ceramic pieces were dipped into the prepared mixtures for 10 seconds, then dried and transferred into a furnace to be melted at different temperatures, which was in the range of 800-1100°C. The selected sample was melted at 900°C for 1 to 4 hours of soaking time. Then, the sample was taken out and observed using Table Top Scanning Electron Microscope (TTSEM) and the hardness of the glaze was tested using Wilson Hardness. The dried glaze powder was characterized using X-Ray Diffraction (XRD). It was found that the best melting temperature and soaking time in producing a perfect glaze with no defect was 900°C with 4 hours of soaking time. Hardness test also showed that the glaze was hardened from 92.5 to 93.7 hv as the temperature increased from 900 to 1000°C. XRD results confirmed the presence of boron oxide, kaolinite, feldspar, and sodium silicate.