“…In order to examine the difference in the generated phases by the sintering additives near the firing temperature, powder X-ray diffraction analysis was performed on each sintering additive treated at 750 ∼ 980 • C. The change of generated compounds by the heat-treated temperature of additive A and C is shown respectively in Figs. 5 and 6, and the generated compounds after treating at 850 • C are shown in Table 1 CuNb 2 O 6 , CuTi 2 Nb 2 O 10 and CuO at 850 • C, but these compounds disappear with the increased treatment temperature and produces the composite compound Cu 4 TiNb 4 O x , which promotes alumina sintering, in almost a single phase at 900 • C and higher [5]. On the other hand, sintering additive C, which contains 34.8mol% of Ag 2 O, produces primarily AgNbO 3 and CuO at 750 • C, but these compounds decrease as the treatment temperature rises, and produces the compound (called Cu 4 TiNb 4 O x solid solution), which has the same diffraction pattern as Cu 4 TiNb 4 O x at 800 • C and higher.…”