TY - JOUR
T1 - Growth Stage Kinetics in the Synthesis of Al2O3/Al Composites by Directed Oxidation of Al-Mg and Al-Mg-Si Alloys
AU - Venugopalan, H.
AU - DebRoy, T.
N1 - Funding Information:
The authorsw ish to thank Dr K. Tankalaf or useful discussionsa nd Professor R. Roy for his interest in the work. This work was supported by the National ScienceF oundation,D ivision of Materials Researchu nder Grant No. DMR-9118075.
PY - 1996
Y1 - 1996
N2 - Although synthesis of ceramic matrix composites by the directed oxidation process offers significant advantages over traditional composite processing routes, the scientific basis for the process is not fully understood. This paper is addressed to understanding the mechanism of composite growth from Al-Mg and Al-Mg-Si alloys theoretically and experimentally. Analysis of the oxidation kinetics of Al-Mg and Al-Mg-Si alloys for various oxygen pressures, temperatures and durations of oxidation, obtained in this study and reported in the literature, demonstrates that the growth kinetics can be tailored by the control of alloy composition. For the Al-Mg alloys, transport of oxygen through a thin alloy layer near the surface controls the growth rate. When Si is added to the alloy, the oxidation mechanism is completely changed. The rate of oxidation of Al-Mg-Si alloys depends on the transport of electronic species through a thin MgO layer at the top surface of the composite. Apart from contributing to a more complete understanding of the growth stage, the mechanism of composite growth will serve as a basis for improving growth rates.
AB - Although synthesis of ceramic matrix composites by the directed oxidation process offers significant advantages over traditional composite processing routes, the scientific basis for the process is not fully understood. This paper is addressed to understanding the mechanism of composite growth from Al-Mg and Al-Mg-Si alloys theoretically and experimentally. Analysis of the oxidation kinetics of Al-Mg and Al-Mg-Si alloys for various oxygen pressures, temperatures and durations of oxidation, obtained in this study and reported in the literature, demonstrates that the growth kinetics can be tailored by the control of alloy composition. For the Al-Mg alloys, transport of oxygen through a thin alloy layer near the surface controls the growth rate. When Si is added to the alloy, the oxidation mechanism is completely changed. The rate of oxidation of Al-Mg-Si alloys depends on the transport of electronic species through a thin MgO layer at the top surface of the composite. Apart from contributing to a more complete understanding of the growth stage, the mechanism of composite growth will serve as a basis for improving growth rates.
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U2 - 10.1016/0955-2219(96)00068-4
DO - 10.1016/0955-2219(96)00068-4
M3 - Article
AN - SCOPUS:0002969494
SN - 0955-2219
VL - 16
SP - 1351
EP - 1363
JO - Journal of the European Ceramic Society
JF - Journal of the European Ceramic Society
IS - 12
ER -