Nanotechnology: Novel Electrodeposited Nanocrystalline Metals and Composites

纳米技术：新型电沉积纳米晶金属和复合材料

• 批准号: 9871980
• 负责人: Carl Koch
• 金额: $ 55.82万
• 依托单位: North Carolina State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-08-15 至 2002-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9871980&HistoricalAwards=false
• 关键词: Nanotechnology; Novel; Electrodeposited; Nanocrystalline; Metals

9871980 Koch The focus of this research is to develop artifact-free nanocrystalline materials by electrodeposition. Electrochemical parameters that control the grain size and chemistry of copper and zinc nanocrystalline films are a central theme of the research. The effects of chemical addition agents to the bath and the waveform of a periodic, pulsed-current deposition are studied. For comparison purposes selected nanocrystalline samples are also prepared by mechanical attrition followed by powder compaction and by pulsed-laser ablation. Closely coupled with these processing studies is atomic level characterization of the nanocrystalline grain-boundary structure and chemistry using high-resolution transmission electron microscopy and analytical electron microscopy to provide feedback on the effects of processing variables. A goal of the synthesis and characterization studies is the processing of the nanocrystalline metals with a range of grain sizes from about 2 to 50 nm and the introduction of nanodispersoids at 1 to 10 volume percent. Into each nanocrystalline metal "hard" and "soft" (polystyrene) nanodispersoids are introduced during the electrodeposition process. This provides unique model systems to determine mechanical properties as a function of nanocrystalline grain size, test temperature, and strain rate. The influence of the nanoscale dispersoids on mechanical deformation and shear banding is of special interest. The data obtained should allow us to construct better models for the deformation and fracture behavior of nanocrystalline materials. This award is a selection under the NSF 98-20 initiative on Functional Nanocrystalline Materials. %%% In comparison to more conventional means to prepare nanocrystalline metals (e.g., gas phase condensation or mechanical attrition), electrodeposition has the following advantages: i) it is a relatively simple operation with low- cost equipment; ii) dense, void-free deposits can be prepared directly without need for consolidation; iii) current or plating-bath chemistry may be used to control grain size, and hence properties, of the nanocrystalline deposit; and iv) nanocomposites with unique properties can be formed by codeposition of nanoparticulates within the metal matrix. ***

小行星9871980 本研究的重点是电沉积法制备无人工痕迹的纳米晶材料。 控制铜和锌纳米晶薄膜的晶粒尺寸和化学性质的电化学参数是研究的中心主题。 研究了化学添加剂对镀液的影响以及周期性脉冲电流沉积的波形。 为了比较的目的，选择的纳米晶体样品也通过机械研磨，然后通过粉末压实和脉冲激光烧蚀来制备。 与这些加工研究密切相关的是使用高分辨率透射电子显微镜和分析电子显微镜对纳米晶晶界结构和化学进行原子级表征，以提供加工变量影响的反馈。 合成和表征研究的一个目标是加工具有约2至50 nm的晶粒尺寸范围的纳米晶金属，并以1至10体积%引入纳米分散体。 在电沉积过程中，将“硬”和“软”（聚苯乙烯）纳米分散体引入到每个纳米晶体金属中。 这提供了独特的模型系统，以确定作为纳米晶晶粒尺寸，测试温度和应变速率的函数的机械性能。 纳米弥散体对机械变形和剪切带的影响是特别感兴趣的。 所获得的数据应使我们能够构建更好的模型的变形和断裂行为的纳米晶材料。 该奖项是根据NSF 98-20功能纳米晶体材料倡议的选择。 与制备纳米晶金属的更常规的方法（例如，气相冷凝或机械研磨），电沉积具有以下优点：i）它是用低成本设备的相对简单的操作; ii）可以直接制备致密的无空隙沉积物而不需要固结; iii）电流或镀浴化学可以用于控制纳米晶存款的晶粒尺寸，并因此控制其性质;和iv）具有独特性能的纳米复合材料可以通过纳米颗粒在金属基体内的共沉积形成。 ***