Abstract
The ferromagnetic Al2O3-based cermets with different ratios of Co and Co–50Ni alloys were successfully prepared by combustion synthesis in thermal explosion (TE) mode. The reaction process, microstructure, and magnetic property of cermets were investigated. The relative density of cermets can be over 95% via uniaxial loading at the time of ignition when the cermets are hot and ductile. In Al2O3–Co cermets, β-Co and α-Co co-exist at room temperature with average size of less than 10 μm and disperse homogeneously in the matrix, while in Al2O3–(Co–50Ni) cermets, the network-like Co–50Ni alloy can infiltrate into the boundary gaps of Al2O3 particles. The ferromagnetic Co and Co–50Ni alloys are responsible of the magnetic properties of Al2O3-based cermets. The saturation magnetization strongly depends on the magnetic characteristics and ratios of ferromagnetic phases. Al2O3–(Co–50Ni) cermets have soft magnetic properties with high magnetic susceptibility and low coercive force.
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Acknowledgements
An acknowledgement is due to associate professors Fan Li and Haibo Huang for the SEM facility and associate professor Xun Xiao for the XRD facility in Analysis and Testing Center of SEU. The authors also would like to thank to Mr. Xun Dong and Mr. Yancheng Zhang for the valuable discussions in the experiments.
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Lu, T., Pan, Y. Combustion synthesis of ferromagnetic Al2O3-based cermets in thermal explosion mode. J Mater Sci 45, 5923–5928 (2010). https://doi.org/10.1007/s10853-010-4672-4
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DOI: https://doi.org/10.1007/s10853-010-4672-4