| Ni-Al₂O₃ composite powders were prepared by reduction of Ni^(++) from ammoniacal nickel sulfate solution on alumina core by hydrogen gas at elevated temperature and pressure. The reduction rate and the porperties of nickel layer were investigated by SEM, X-ray, size and chemical analysis. The reduction of Ni^(++) showed the maximum value when the molar ratio of NH₃/Ni^(++) was 2. In order to prevent the agglomeration of Ni powder and act as catalysis for reduction, Fe^(++) should be required and the anthraquinone was slightly influenced as catalysis. The concurrent addition of Fe^(++) and anthraquinone catalytically increased nickel deposition reaction. Optimum condition obtained in this study was reduction temperature 130℃, stirring speed 700rpm, hydrogen partial pressure 350psi and reduction time 45mins. Then the prepared composite powder obtained uniform and continuous nickel coating layer of nodule shape on alumina particles. |
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