Thermal expansion, physico-mechanical properties and microstructure of cordierite synthesized from different starting materials

The scope of this study is to investigate the effect of starting materials on some properties of synthesized cordierite. Based on the stoichiometric composition of cordierite, two batches (batch 1 and 2) were prepared from kaolin, talc, bauxite, fumed silica and magnesium hydroxide materials. The materials were grinded and mixed well at firing temperatures up to 1400 °C for 4 h. The mineral and chemical compositions of the raw and fired materials are determined using XRD and XRF techniques, respectively. Densification properties, microstructure and the thermal expansion coefficient of the fired samples were determined. The refractoriness under load and compressive strength was determined. It was concluded that cordierite is the only crystalline phase recorded in the two batches. Batch no.2 has higher density (2.28 g/cm3), lower porosity 0.5 % and an excellent thermal coefficient (0.436.10-6 K-1) at 1000 °C. Both batches show high compressive strength as well as refractoriness under load.