A Review of Metallic Fractal Aggregates

• 作者: Claude Rioux Michel Piché Rodolfo J. Slobodrian
• 来源期刊: 金属学报(美国)
• 学科: 化学
• 关键词: Fractals MONOMERS AGGREGATES METALS ALLOYS
• 年，卷（期）: jsxbmg,（2）
• 页码范围: 17-24
• 页数: 8页
• 分类号: O6

摘要

Metals are the main components of the Earth’s mass and are characterized by high thermal and electrical conductivity as well as high reflectivity of electromagnetic fields. Finely divided metals are efficient catalysers and this indicates the relevance of surfaces when their ratio to volume becomes large. This is a characteristic of fractal aggregates and their constituent monomers (spheroidal or other) in the micrometer to nanometer scales. Exotic fern shaped aggregates are also produced. All aggregates exhibit large ratios of surface to volume. Condensation of metallic vapours allows to obtain particle sizes much smaller than those obtained via grinding techniques and far superior in purity. Exotic alloys of non miscible metals have been obtained at the micrometer scale. Thermal and laser evaporation methods of metals followed by condensation are described. Low gravity aggregation experiments were also carried out on aircraft in parabolic flight.