以α-Bi2O3和WO3粉末为原材料，利用铋的半金属性，通过高能球磨制备核壳结构的Bi/WOx复合粉体材料，通过对粉末的微观形貌与结构的分析，进一步研究富氧壳层对复合粉体耐热氧化性和禁带宽度的影响。结果表明，核壳结构的Bi/WOx复合粉体的壳层为非晶态WOx，壳层厚度约30 nm，内核为结晶完好的六方金属Bi，内核的平均粒径为20~90 nm。Bi/WOx复合材料在富氧环境下耐热氧化性较好，这是由非晶态WOx中O原子的扩散速率大决定的。球磨时间是影响Bi/WOx复合粉末微观形貌、结构和性能的重要因素。当球磨时间为5 h时，产物中存在单斜WO3纳米晶，禁带宽度约1.72 eV；随球磨时间延长，产物形貌更均一，禁带宽度蓝移，这是由壳层非晶态WOx中过量O原子和明显的结构缺陷所致；当球磨时间延长至15 h时，禁带宽度为2.1 eV；进一步延长球磨时间，禁带宽度红移。%The core-shell Bi/WOx composite powders material were prepared via high energy ball milling fromα-Bi2O3 and WO3, based on the half metallic bismuth. The influence of oxygen-enriched content in the WOx shell on the thermal stability properties and the forbidden band width were studied via analyzing the micro- morphology and structure of Bi/WOx composite powders. The results show that the shell of Bi/WOx composite powders is amorphous WOx with the thickness of about 30 nm, and the core is hexagonal Bi of 20-90 nm in diameter. In oxygen atmosphere, the core-shell Bi/WOx composite material shows excellent thermal stability, which is due to the low diffusion rate of oxygen in WOx shell. The morphology, microstructure and properties of core-shell Bi/WOx composite powders are sensitive to ball milling time. There are monoclinic WO3 nanocrystals exist in the products with forbidder band width of 1.72 eV, when the milling time is 5 h. With the increasing of milling time, the morphology and size become more uniform. Meanwhile, the shell structure completely transform to amorphous WOx with surplus oxygen and structure defects, which lead to the blue-shift of forbidden band width. When the milling time is extended to 15 h, the forbidden band width of the product is 2.1 eV. With the milling time further extension, the red-shift of forbidden band width for the products milled beyond 15 h can be observed.
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