The Study On Reparation And Properties Of Aluminum Titanate Ceramic

Aluminium titanate as a kind of new ceramic material has special capability as thermal expand coefficient which is close to zero, low transmit heat coefficient, high melting point, thermal shock resistance and thermal beat resistance. It's high temperature resistance is the best of low expand materials at present. Aluminium titanate material is a kind of excellent material which has high melting point and low dilatability. According to aluminium titanate's different properties, it can be used differently. Such as it can be used as vehicle's engine component for it's good thermal resistance and high melting point. As it has high thermal beat resistance and low soakage to melting metal, it can be used in colored metal found and glass industry. It is used as inner liner compound tie-in material. But the material has two fatal defects: one was that the crystal was very large anisotropy which made its mechanical strength very low because there was much crack in the material when it cooled. Another was that itwould be very easy to decompose into rutile and corundum between 750～1300℃, which made it lose the excellent properties. So its application was restricted.The paper makes an overview about the microstructure of AT, simply thermal stability, thermal decomposition, low thermal expansion, coefficient mechanical strength, as well as the factors that influenced the properties mentioned above. Nevertheless, the article stated the making method of the AT powder. The AT powder is prepared by co-precipitation method using NH₄HCO₃ as precipitator. The progress in the research of AT ceramic is the key and it is showed that the PH is playing an important role in the co-precipitation of AT .Meanwhile, methods used to suppress thermal decomposition and how to improve the mechanical strength are also discussed, especially, the influence of different additive, suchasMgO,Fe₂O₃,SiO₂ and ZrO₂ on the capability of AT ceramic are discussed. Aluminum titanate is well stabilized by introducing ferric oxide and compositing with mullite. Aluminum titanate received a thermal stress from mullite around it because their differences of structure and property. The aberration of aluminum titanate was not easy to happen, so the thermal stability of aluminum titanate was promoted. After ferric oxide was added, the lattice constant of c increased because Fe³⁺ and Si⁴⁺ replaced Al³⁺ and Ti⁴⁺, the aberrance extent of aluminum titanate decreased, crystal latice of aluminum titanate was made to be stable, and the thermal stability was promoted.The thermal expansion coefficient of aluminum titanate-mullite composite is containing. Sintering temperature is important to the final properties of AT ceramic. It can be obtained AT ceramic of crystal granularity uniformity and component equality at proper temperature and heat preservation time.