(Sr_<1-x>Ba_x)SiO_3(x≦0.2)セラミックスのち密化に及ぼすAl_2O_3添加の影響

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Effect of Al_20_3 on the sintering of SrSi0_3 and (Sr_<1-x>Ba_x) Si0_3 (x≦0.2) ceramics was studied. Bulk densities, microstructures, chemical compositions and lattice constants of metasilicates were measured for the fired bodies. (1) An orthosilicate was formed as a precursor when an equimolor mixture of SrC0_3 and Si0_2 was heated above 700℃, and the orthosilicate and Si0_2 reacted to form a metasilicate at higher temperature. (2) The calcined powders of SrC0_3 and Si0_2 did not sinter at 1450℃. (3) Substitutional solid solutions were formed in the composition range (Sr_<1-x>Ba_x) SiO_3(≦x0.2) at 1300℃. They did not sinter like SrSi0_3 powders. (4) When 3-5 wt% of Al_20_3 was added, the powder of (Sr_<1-x>Ba_x) Si0_3 (0≦x≦0.1) densified rapidly at about 1300℃. A glassy phase was formed at grain: boundaries. (5) The average chemical composition of this glassy phase was 2 (Sr, Ba) 0・2Si0_2・Al_20_3 and that of the crystalline phase was (Sr,Ba) ・SiO0_2. (6) When Al_20_3 was added, the sintering temperature decreased with increasing BaO content. The BaO content in the metasilicate crystal was less than that expected from the mixing ratio indicating that BaO was concentrated at the glassy phase preferentially.
社団法人日本セラミックス協会の論文
1988-01-01