Balázsi K, Varanasi D, Horváth Zs E, Furkó M, Cinar F S, Balázsi C
Thin Film Physics Department, Institute of Technical Physics and Materials Science, Centre for Energy Research, Konkoly-Thege M. Str. 29-33, Budapest, 1121, Hungary.
Metallurgical and Materials Engineering Department, 34469, Maslak, Istanbul, Turkey.
Sci Rep. 2022 May 17;12(1):8250. doi: 10.1038/s41598-022-12456-2.
The effect of the pressureless post-sintering in hydrogen on the structural and mechanical properties of the hot isostatic pressed AlO prepared by oxidized AlN powder has been studied. The micrometer size AlN powder has been oxidized in air at 900° C and sintered by hot isostatic pressing (HIP) at 1700 °C, 20 MPa nitrogen atmosphere for 5 h. Pressureless sintering (PS) has been applied for all HIP sintered samples in H gas at 1800° C for 10 h. It has been shown that the oxidation caused a core-shell AlN/AlO structure and the amount of AlO increased with increasing of the oxidation time of the AlN powder. For the first time, the green samples obtained from oxidized AlN powder have been successfully sintered first by HIP followed by post-sintering by PS under hydrogen without adding any sintering additives. All post-sintered samples exhibited the main α-AlO phase. Sintering in H caused the full transformation of AlN to α-AlO phase and their better densification. Therefore, the hardness values of post-sintered samples have been increased to 17-18 GPa having apparent densities between 3.11 and 3.39 g/cm.
研究了氢气中无压后烧结对由氧化氮化铝粉末制备的热等静压氧化铝结构和力学性能的影响。将微米尺寸的氮化铝粉末在900℃的空气中氧化，并在1700℃、20MPa氮气气氛下通过热等静压（HIP）烧结5小时。对所有热等静压烧结的样品在氢气中于1800℃进行10小时的无压烧结（PS）。结果表明，氧化导致了核壳结构的氮化铝/氧化铝，且氧化铝的量随着氮化铝粉末氧化时间的增加而增加。首次成功地将由氧化氮化铝粉末获得的生坯样品先通过热等静压烧结，然后在氢气中进行无压后烧结，且未添加任何烧结添加剂。所有后烧结样品均呈现主要的α-氧化铝相。在氢气中烧结导致氮化铝完全转变为α-氧化铝相且致密化程度更好。因此，后烧结样品的硬度值提高到了17 - 18 GPa，表观密度在3.11至3.39 g/cm之间。
