| This dissertation has systematically studied the preparation and growth mechanism of CO3BO5 whiskers. Appropriate materials, flux, the flux ratio and the reaction conditions were optimized. The whiskers were characterized by XRD, SEM, TEM and SAED, the growth mechanism of the whiskers was explored. The main contents are as following:(1) Through Single factor experiments, cobalt chloride and borax were selected as cobalt source, boron source, respectively, and the ratio of the materials is in the range of 3:2-3:3; potassium chloride was selected as the flux, and the ratio of the flux is 0.75-1.25 of the summation quantity of cobalt salts and borate materials; the reaction temperature is between 850℃-900℃, and the reaction time is between 2-3 h. High length ratio of CO3BO5 whiskers can be prepared under these conditions.(2) Through orthogonal experiments, the range and variance analysis, the optimum prepartion conditions of Co3BO5 whiskers were determined as:the ratio of Co:B is 3:2.25, the ratio of flux is 0.75, the reaction temperature is 900℃, and the reaction time is 4 h; the order of the factors affecting the reactions is:temperature> content of flux> ratio of Co:B> reaction time.(3) The prepared whiskers were analyzed and characterized by XRD, SEM, TEM and SAED et al. The results showed that:the whiskers are orthorhombic Co3BO5, the average length of the whisker is more than 500μm, most diameters are between 0.5-5μm with a few diameters up to 10μm, the average length ratio is above 100 within high ratio. It is a single crystal structure that grows along the [231] direction.(4) Through estimating the precursor product, the growth mechanism of the CO3BO5 whiskers was explored. The Co3BO5 whiskers prepared by the crucible outer wall was considered as the gas phase reaction growth, and after sintering, the dissolved whiskers within a block can be explained by dissolving-depositing mechanism.Based on the selected preparation conditions of Co3BO5 whiskers, Co3B2O6 and Co2B2O5 whiskers were obtained. Reagents were chosen as cobalt chloride and boric acid, flux is potassium chloride, the optimized conditions are:reaction temperature is 850℃, reaction time is 1.5 h, the ratio of cobalt:boron is 1:2 and 1:3 to 1:4 respectively. The prepared Co3B2O6 whiskers are brittle and have some defects. The crystals'surfaces have taken on some cracks and ruptures, and the average length of the whiskers is more than 500μm, most diameters are between 10-100μm. Contrasted with Co3B2O6 whiskers, the quality of Co2B2O5 whiskers was improved. The fibriform crystals are increased and the clavas are reduced. The cracks and ruptures are reduced also.The average length of the whiskers are 200-500μm, most diameters are between 2-20μm.During the preparation of Co3BO5 whiskers, a hexagonal plate Co3O4, a new morphology, was discovered surprisingly. The synthetic material, conditions of the hexagonal plate Co3O4 were optimized and the final experimental conditions are:the material ratio is CoCl2·6H2O: NaOH:H3BO3= 1:5:1; the reaction temperature is 750℃, the reaction time is 2 h. XRD results show that the final product is Co3O4; SEM results show that their shapes are regular hexagonal piece, the surface is clean, smooth, no cracks and other defects, the side range is between 2-10μm, the side image shows a layer structure. TEM results show that the product is hexagonal plate single crystal, crystal is perfect, the surface is smooth with no holes. SAED and HRTEM figures show that the distance between the strips is 0.24 nm, corresponding to the [311] crystal face.
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