Heat resisting low expansion zirconyl phosphate-zircon composite bodies and process for producing the same

摘要

Heat resisting low expansion zirconyl phosphate-­zircon composite bodies are disclosed, which contain zirconyl phosphate and zircon as a main crystalline phase and a secondary crystalline phase, respectively. The heat resisting low expansion zirconyl phosphate-­zircon composite bodies have a coefficient of thermal expansion in a temperature range from room temperature to 1,400°C being not more than 30×10⁻⁷/°C and a melting point being not less than 1,600°C. The composite bodies have a chemical composition essentially consisting of 58.2 to 65.4% by weight of ZrO₂, 17.4 to 37.1% by weight of P₂O₅, and 1.5 to 19.0% by weight of SiO₂. The heat resisting low expansion zirconyl phosphate-zircon composite bodies optionally contain MgO and Aℓ₂O₃ in a total amount of not more than 2.5% by weight or 0.1 to 4% by weight of Nb₂O₅. A process for producing such zirconyl phosphate-zircon composite bodies is also disclosed.