Synthesis, characterisation and sintering behaviour influencing the mechanical, thermal and physical properties of cordierite-doped TiO2

Cordierite–TiO2 composite (5–20 wt.%) ceramics for various stoichiometric compositions were synthesised using conventional techniques with standard raw materials. The green composite ceramic samples obtained were dried at 100 °C for 12 h, followed by pre-sintering at 800 °C for 3 h. The powders were dry milled for 2 h and then compacted at 240 MPa to form pellets. The sample pellets were sintered at temperatures in the range of 600–1300 °C for 3 h. The study of the different phases of the samples was performed using X-ray diffraction. The poor mechanical properties of cordierite have attracted the use of TiO2 as a dopant. A study on the influence of TiO2 addition to flexural strength, fracture toughness, hardness, bulk density and thermal expansion was performed. Vickers hardness value of the cordierite–TiO2 composites of 6.46 GPa is higher than other compositions of cordierite. The cordierite–TiO2 exhibited a fracture toughness of 3.28 MPa m1/2. The flexural strength of the cordierite–TiO2 was 158.47 MPa. The effect of thermal expansion was very low in the cordierite–TiO2. Studies using X-ray diffraction and scanning electron microscope imaging on samples sintered at 1300 °C confirmed the presence of cordierite, along with small amounts of rutile and cristobalite.