Description

Mullite has long been used as a refractory material. Its properties include: · Good high temperature strength · Good thermal shock resistance · Excellent thermal stability · Resistance to most chemical attack; it has excellent stability in acid metal slags and is insoluble in most acids · Resistance to oxidation and attack by furnace atmospheres · Resistance to abrasion · Good electrical resistivity The approximate limiting temperatures of use are ***0oC in air and ***0oC in vacuum. Propertyï&frac*4;š Density (g/cm3)ï&frac*4;š3.*3 Young’s Modulus (GPa)ï&frac*4;š**0 Fracture Toughness (******1/2)ï&frac*4;š**4 Modulus of Rupture (MPa)ï&frac*4;š**0 Thermal Expansion Co-Efficient (x***6 /°C)ï&frac*4;š4.**5.6 Thermal Conductivity (W/m.K)ï&frac*4;š4.**6.0 (*******0°C) Maximum Operating Temperature (°C)ï&frac*4;š***5°C in air Applicationsï&frac*4;š largest use of mullite based products is in refractories. The glass and steel industries are two main markets. The next largest user of mullite is the ceramic industry mostly in kiln furniture items such as kiln setter slabs and posts for supporting ceramic ware during firing. The aluminium and petrochemical industries also use mullite-based aggregates for applications requiring chemical attack resistance, thermal shock resistance and hot-load strength. New mullite materials that have more controlled mechanical and physical properties and are providing opportunities for a wider use of the material. The good mechanical properties at high temperatures of high purity mullites have made them potential high temperature engineering ceramics, for example in turbine engine ***** is alo a leading candiate material for high-strength infrared transmitting windows.