Sintered alumina product

A sintered product has the following chemical analysis, in mass percentages on the basis of oxides: Al2O3: the remainder to 100%, 0.26% < = Na2O < = 4%, 0% < = oxides other than Al2O3 and Na2O < = 6%, with the proviso that SiO2 < = 2%, the following crystalline phases, in mass percentages on the basis of the total amount of crystalline phases: 5% < = beta-alumina < = 37%, 0% < = beta-alumina < = 3%, and 0% < = beta-alumina < = 3%. Less than 6% of crystalline phases other than beta-alumina and alpha-alumina, up to the balance of alpha-alumina of 100%. 一种烧结产品，其具有：-以下化学分析，以基于氧化物的质量百分比计：Al2O3：至100％的余量，0.26％≤Na2O≤4％，0％≤除了Al2O3和Na2O之外的氧化物≤6％，条件是SiO2≤2％，-以下结晶相，以基于结晶相总量的质量百分比计：5％≤β-氧化铝≤37％，小于6％的除了β-氧化铝和α-氧化铝之外的结晶相，至100％的余量：α-氧化铝。