| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an alumina sintered body that can be sintered at a low burning temperature, can reduce the cost required in a burning step, and has high withstand voltage characteristics. <P>SOLUTION: The alumina sintered body has alumina crystals as a main phase and an amorphous grain boundary phase. The amorphous grain boundary phase is a grain-boundary glass phase having a glass component in which at least one of either CaO or MgO is added to SiO<SB POS="POST">2</SB>, and at least one type of oxide selected from rare-earth elements and elements in Group IV of the periodic table included in the glass component as a specific component. When a composition ratio of the main phase and the grain boundary glass phase is alumina: glass component: specific component=a:b:c (a+b+c=100 wt.%), in a triangular coordinate of which peaks are alumina, the glass component, and the specific component, a point (a,b,c) is within a range surrounded by four points, A(98.0,1.0,1.0), B(90.0,5.0,5.0), C(93.5,5.0,1.5), and D(97.8,2.0,0.2). <P>COPYRIGHT: (C)2012,JPO&INPIT |
