| 摘要 |
<p>A ceramic material for use in insert-casting, which contains not less than 65% by volume of aluminum titanate as a crystalline phase. The average particle diameter of crystals of the aluminum titanate is not less than 10 mu m, and not more than 20% by volume of a glass phase containing a rare earth element in an amount of 0.5 to 16% by weight when calculated in the form of an oxide is contained. Young's modulus is 50 to 2,000 kgf/mm<2>. A process for producing the same is also disclosed, which comprises the steps of preparing a powder by mixing a material, as an A l 2O3 source material, containing not more than 96% by weight of A l 2O3 and having an average particle size of not less than 3 mu m, a material having an average particle diameter of not more than 3 mu m as a TiO2 source material, and a given rare earth element in an amount of 1.8% by weight when calculated in the form of an oxide, shaping the powder, and drying and firing the shaped body. The ceramic material may have an actual beak strain of not less than 6 x 10<-><3>. The process for producing such a ceramic material includes a step of cooling the shaped body at a rate of at least not less than 500 DEG C/hr in a temperature range not less than 200 DEG C during and/or after the firing.</p> |
