Porous mullite ceramic composites with needle-like microstructure and zirconia. Processing and properties

P. V. LÓPEZ; A. MOCCIARO; M. F. HERNÁNDEZ; D. RICHARD; N. M. RENDTORFF

Florianópolis

Congreso; 67° Congresso Brasileiro de Cerâmica; 2023

Porous ceramics are used for many functional and structural applications. When they have to support load or pressure it is preferable that ceramics have optimum mechanical behaviour. However, the increase in porosity affects the mechanical properties and consequently its performance. The key to improving these properties is by designing microstructural features. A good approach is to develop composites reinforced with fibers, needles, or grains of materials with higher mechanical strength.The primary aim of this work is to synthesize, by ceramic processing, a novel porous ceramic composites based on acicular mullite (3Al2O3.2SiO2) and sub-micron grains of stabilized zirconia (ZrO2-8Y), (5:1 vol). These composites have the favorable properties of mullite such as low density, low conductivity and thermal expansion, resistance to high temperatures and corrosive environments. The acicular grains of mullite, being defect-free single crystals, act as reinforcement. In addition, zirconia improves mechanical properties, such as mechanical strength and hardness.