볼 밀링한 CuO-Co3O4 혼합분말의 수소환원 거동과 미세조직 특성
Hydrogen Reduction Behavior and Microstructure Characteristics of Ball-milled CuO-Co3O4 Powder Mixtures
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The hydrogen reduction behavior of the CuO-Co3O4 powder mixture for the synthesis of the homogeneous Cu-15at%Co composite powder has been investigated. The composite powder is prepared by ball milling the oxide powders, followed by a hydrogen reduction process. The reduction behavior of the ball-milled powder mixture is analyzed by X-ray diffraction (XRD) and temperature-programmed reduction at different heating rates in an Ar-10%H2 atmosphere. The scanning electron microscopy and XRD results reveal that the hydrogen-reduced powder mixture is composed of fine agglomerates of nanosized Cu and Co particles. The hydrogen reduction kinetics is studied by determining the degree of peak shift as a function of the heating rate. The activation energies for the reduction of the oxide powders estimated from the slopes of the Kissinger plots are 58.1 kJ/mol and 65.8 kJ/mol, depending on the reduction reaction: CuO to Cu and Co3O4 to Co, respectively. The measured temperature and activation energy for the reduction of Co3O4 are explained on the basis of the effect of pre-reduced Cu particles.
Abstract
The hydrogen reduction behavior of the CuO-Co3O4 powder mixture for the synthesis of the homogeneous Cu-15at%Co composite powder has been investigated. The composite powder is prepared by ball milling the oxide powders, followed by a hydrogen reduction process. The reduction behavior of the ball-milled powder mixture is analyzed by X-ray diffraction (XRD) and temperature-programmed reduction at different heating rates in an Ar-10%H2 atmosphere. The scanning electron microscopy and XRD results reveal that the hydrogen-reduced powder mixture is composed of fine agglomerates of nanosized Cu and Co particles. The hydrogen reduction kinetics is studied by determining the degree of peak shift as a function of the heating rate. The activation energies for the reduction of the oxide powders estimated from the slopes of the Kissinger plots are 58.1 kJ/mol and 65.8 kJ/mol, depending on the reduction reaction: CuO to Cu and Co3O4 to Co, respectively. The measured temperature and activation energy for the reduction of Co3O4 are explained on the basis of the effect of pre-reduced Cu particles.
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