Development of cordierite-based low-expansion porcelain tiles with application potential in an underfloor heating system

Abstract

The high coefficients of thermal expansion (CTEs; α) of common porcelain tiles result in deformation, cracking and even breakage after prolonged utilization in an underfloor heating system. Cordierite-based porcelain tiles with low α values have good application potential in underfloor heating systems. Herein, environmentally friendly and low-cost cordierite-based porcelain tiles made with desert sand were presented. The bulk density, linear shrinkage, water absorption, CTE, and modulus of rupture were determined to investigate the sintering stage of this desert sand-based low-expansion porcelain tiles. Powder X-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy analyses were used to characterize the phase changes and microstructures of the materials. The results revealed that mass ratio of SiO₂ to Al₂O₃ (m[SiO₂/Al₂O₃]), mass ratio of MgO to Al₂O₃ (m[MgO/Al₂O₃]), and sintering temperature jointly affected the CTEs of the porcelain tiles. Moreover, the sintering temperature significantly impacted the quantities and morphologies of the cordierite crystals. An increase in the number of columnar-like cordierite crystals during production resulted in a decreased CTE. The results of this study present an effective technique for preparing low-CTE porcelain tiles from natural waste materials. These desert sand-based tiles could be widely applied in underfloor heating systems.