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  • Development of non-oxide ceramic matrix composites based on reactive infiltration and in situ growth of AlN bonding phase
    Kevorkijan, Varužan
    Novel ceramic composites (CMCs) were prepared by reactive infiltration of porous (50-70% T.D.) ceramic preforms and in situ growth of an AlN bonding phase (10-35 vol%) from molten Al alloys. The ... continuity of the forming phases results in a very favourable balance of both physical and mechanical properties. Moreover, becuse the prepared composites have a continuous Al phase (5-15 vol%), they exhibit some traditional macroscopic plasticity, despite being appoximately 70 vol% ceramic. Performs with optimal porosity and permeabilitys were prepared by conventional ceramic processes using commercially avaliable AlN, SiC and Si▫$_3$▫N▫$_4$▫ powders. Different non-oxide species were selected in order to demonstrate the flexibility of the preparation route. Wetting-assisted pressureless infiltration of Al into the preforms was accomplished in nominally pure N▫$_2$▫ or under an argon atmosphere at temperatures between 850°C and 1200°C. The AlN bonding phase was prepared by displacement reactions between Al and selected commercially available nitrides (Si▫$_3$▫N▫$_4$▫, Mg▫$_3$▫N▫$_2$▫, Zn▫$_3$▫N▫$_2$▫, 325 Mesh powders) previously deposited on the surface of the porous ceramic body. Composite growth rates between 0.4-0.6 mm/min were observed and correlated with the interfacial reaction enthalpy change. Initial characterisation of selected mechanical properties (hardness, Young's modulus, compresive and flexural strength, toughness) of composites with the same ratio of forming phases was also performed.
    Vir: Proceedings of the American Society for Composites : Twelfth Technical Conference, October 6-8, 1997, The Dearborn Inn, Dearborn, Michigan (Str. 970-974)
    Vrsta gradiva - prispevek na konferenci
    Leto - 1997
    Jezik - angleški
    COBISS.SI-ID - 5955094

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