Reactive sintered highly transparent AlON ceramics with Y₂O₃‐MgAl₂O₄‐H₃BO₃ ternary additive

Abstract

In this study, highly transparent aluminate oxynitride (AlON) ceramics were prepared via the reactive sintering of Al2O3 and AlN powders using a Y2O3‐MgAl2O4‐H3BO3 ternary sintering additive. The ternary doping process resulted in the efficient preparation of transparent AlON ceramics with small grains and high transmittance as compared to the binary doping (Y2O3‐MgAl2O4) process. The addition of 0.1 wt.% Y2O3‐0.4 wt.% MgAl2O4‐0.12 wt.% H3BO3 resulted in the formation of a 4‐mm‐thick AlON ceramic with high transmittance (81% at 600 nm) and low haze (3.46%). This is the best performance in terms of the thickness and transmittance reported for AlON transparent ceramics prepared by the reactive sintering method.

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

“…[1][2][3][4][5] AlON ceramics can be fabricated by consolidation of AlON powder or solid reaction of Al 2 O 3 /AlN. [6][7][8][9][10] Currently, most of AlON ceramics were prepared by consolidation of AlON powder by different sintering techniques, such as pressureless sintering (PS), [11][12][13][14] PS combined with hot isostatic pressing (HIP), [15][16][17][18][19] hot pressing, 20 and spark plasma sintering. 21,22 Among them, PS is the most favorite way for its low cost and feasibility in practice.…”

“…Aluminum oxynitride (AlON), as one of the transparent polycrystalline ceramics, exhibits excellent optical and mechanical properties, enabling its potential applications in infrared windows/domes and transparent armors 1–5 . AlON ceramics can be fabricated by consolidation of AlON powder or solid reaction of Al 2 O 3 /AlN 6–10 . Currently, most of AlON ceramics were prepared by consolidation of AlON powder by different sintering techniques, such as pressureless sintering (PS), 11–14 PS combined with hot isostatic pressing (HIP), 15–19 hot pressing, 20 and spark plasma sintering 21,22 .…”

Fabrication of AlON transparent ceramics with Si 3N 4 sintering additive

“…On the other hand, sintering additives are usually used to promote densification and sometimes inhibit the grain growth to obtain fully-dense AlON transparent ceramics. They are reported including a single additive as Y 2 O 3 [16,17] and other rare earth [18], MgO [15,19], SiO 2 [20,21], CaCO 3 [22], and LiAl 5 O 8 [23,24], binary additives as Y 2 O 3 -La 2 O 3 [13,[25][26][27] and Y 2 O 3 -MgO [14,28], and complex ternary additives as CaF-Y 2 O 3 -SiO 2 [29] and Y 2 O 3 -MgAl 2 O 4 -H 3 BO 3 [30]. Although the reported sintering additives are valid in the AlON system for the enhancement of densification and improvement of optical properties of transparent ceramics, the sintering temperature was still high, such as pressureless sintering at 1860-1940 ℃ and HIP at 1800-1900 ℃.…”