Study on Aluminium Nitride Ceramics Properties
2010
Hochschulschrift
Zugriff:
98
In this study, five commercial aluminum nitride powders code-named TY, TWN, TK-E, TK-H and TK-HT respectively, are used in hydrolysis tests. The results show the order of the ability to resist hydrolysis: TY> TK-HT> TK-E> TK-H> TWN. The problem of powder hydrolysis is resolved by sintering the powders into compact ceramic substrates with good thermal conductivities - temperatures are set at 850, 950 and 1050 ℃ respectively with oxygen flow passing for 1 ~ 4 hours. A layer of alumina (Al2O3) - an important role in resisting hydrolysis - is formed on top of aluminum nitride powder. With the 1050 ℃-sintered-for-four-hours TK-H immersed in water at 60 ℃ for four hours, the pH only increases to 8.08, much less than 10.3 as in the case of unsintered TK-H. The alumina layer thickness of sintered TK-H is estimated to be around 130 nm. The densities and thermal conductivities of 1800 ℃- and 1850 ℃-dry-pressed (1 ton/cm2) TK-HT ceramic are measured and compared to those of the commercial tape-casting ceramic. Both the densities and thermal conductivities of dry-pressed ceramic are higher than those of commercial one. As for the influence of dry-pressed temperature, both the densities and thermal conductivities of 1850 ℃-dry-pressed TK-HT ceramic are higher than those of 1800 ℃-dry-pressed one. The strength tests for 1800 ℃-dry-pressed TK-HT specimen show: average failure strength 285.09 Mpa, Weibull modulus 10.87, micro-hardness 9.43 GPa, fracture toughness 11.66 MPa.m1 / 2. The SEM analysis of low-density aluminum nitride (σ = 219 MPa) shows that the destruction of specimens are caused by large grain (10um).
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Study on Aluminium Nitride Ceramics Properties
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Autor/in / Beteiligte Person: | Chang, Chih-Chieh ; 張智傑 |
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Veröffentlichung: | 2010 |
Medientyp: | Hochschulschrift |
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