Pressureless sintering of highly transparent AlON ceramics with CaCO3 doping

Pressureless sintering of transparent AlON ceramic with assimilable γ‐Al2O3 as sintering promoting additives

“…Even though the distribution of grain size is not uniform and the shape of grains is not regular, the surfaces show a dense structure. The concentration of γ‐Al 2 O 3 nano‐powder seems to have no obvious effects on the distribution of grain size, which is different from traditional sintering additives 27,28 . The mean grain size of all the samples is about 10 μm, which is much smaller than other AlON samples doped with traditional sintering additives 29,30,26,32 …”

“…The concentration of γ-Al 2 O 3 nanopowder seems to have no obvious effects on the distribution of grain size, which is different from traditional sintering additives. 27,28 The mean grain size of all the samples is about 10 μm, which is much smaller than other AlON samples doped with traditional sintering additives. 29,30,26,32 Five valid indentations were made at the same load of 0.3 Kg for each sample, as can be seen in the inserted SEM image of 3,15,31,33 The in-line transmittance parameters of AlON ceramics were determined and the result is shown in Figure 10.…”

Study on robust additive of CaCO3 for fast fabrication of highly transparent AlON ceramics by pressureless sintering

“…25 Therefore, the phase assemblage and morphology evolution of three AlON powders of different PSD during heating were first thoroughly observed. To evaluate the role of CaCO 3 on densification, two groups of samples were investigated, that is, no CaCO 3 addition and 0.3 wt.% CaCO 3 addition (transparent AlON ceramics with 83% transmittance were obtained by 0.3 wt.% CaCO 3 doping in the previous work 33 ). Accordingly, all the samples in this work were named after their PSD and additive doping weight ratio.…”

“…Many additives, such as Y 2 O 3 , 6,24 La 2 O 3 , 30,31 MgO, 27,32 SiO 2 , 17,18 CaCO 3 , 33 and GeO 2 , 34 have been employed as sintering additive to prepare transparent ceramics including AlON. Among them, CaCO 3 successfully served as sintering additive to obtain highly transparent AlON ceramics (up to 85% at ∼3700 nm).…”

“…Among them, CaCO 3 successfully served as sintering additive to obtain highly transparent AlON ceramics (up to 85% at ∼3700 nm). 33 It is known that CaCO 3 decomposes into CaO + CO 2 at 800-900 • C, which implies that CaCO 3 can serve as sintering additive by mean of CaO at high temperature. As a matter of fact, CaO is an effective sintering additive for preparing of YAG, MgO⋅1.5Al 2 O 3 , MgAl 2 O 4 , and Y 2 O 3 transparent ceramics.…”