Effect of heating rate on properties of transparent aluminum oxynitride sintered by spark plasma sintering
- Dalian Maritime Univ. (China)
- San Diego State Univ., CA (United States)
Abstract High heating rates ranging from 50 to 250°C/min are selected to rapidly sinter transparent aluminum oxynitride (Al ON ) ceramics by spark plasma sintering ( SPS ) at 1600°C under 60 MPa using a bimodal Al ON powder synthesized by the carbothermal reduction and nitridation method. With 1 minute holding time before cooling, all the specimens show high density and high transparence. The maximum transmittance is up to 74.5%‐80.6%, where the maximum transmittance is positively correlated with the heating rate. Further analysis reveals that faster heating rates enable the decrease in the amount of the Al ON phase decomposed into the α‐Al 2 O 3 and AlN phases during heating. These α‐Al 2 O 3 and AlN phases have to be converted back to Al ON at the final stage of sintering, which indicates that a decrease in the amount of the α‐Al 2 O 3 and AlN phases via the boosted heating leads to the higher transmittance of the Al ON ceramics. The high heating rates and short holding duration of the SPS utilized in this study result in the fine grain size of the obtained ceramics (1‐6 μm) compared to that of the Al ON ceramics fabricated by the conventional sintering method. This effect of high heating rates is confirmed by the coupled densification‐grain growth modeling. In turn, the obtained Al ON specimens exhibit a Vickers hardness of 15.87‐16.62 GPa.
- Research Organization:
- San Diego State Univ., CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division; National Key Research and Development Program of China; Dalian Science and Technology Innovation Fund; USDOE
- Grant/Contract Number:
- SC0008581; 2017YFB0310300; 2018J12GX032; DE‐SC0008581
- OSTI ID:
- 1611089
- Alternate ID(s):
- OSTI ID: 1468495
- Journal Information:
- Journal of the American Ceramic Society, Vol. 102, Issue 2; ISSN 0002-7820
- Publisher:
- American Ceramic SocietyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
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