高强度泡沫镍生产工艺研究

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	高强度泡沫镍生产工艺研究
	刘伟华
学位类型	硕士
导师	郑志 ; 于清
	2012
学位授予单位	中国科学院金属研究所
学位授予地点	北京
学位专业	材料工程
关键词	泡沫镍纵向抗拉强度 Pvd改型面密度均匀性热处理 Nickel Foam Long Tensile Strength Pvd Foam Modified Uniform Of Surface Density Heat Treatment
摘要	" 泡沫镍由于具有三维网状结构、孔隙率高、比表面积大、质量均匀，因此成为MH-Ni及Cd-Ni电池理想的电极基板材料。但是近年来随着对镍的需求不断增加，镍价持续在高位运行。为了降低成本，低面密度泡沫镍成为主要研发方向。低面密度泡沫镍为了适应连续式电池生产，提高纵向抗拉强度是低面密度泡沫镍必须解决的一个问题。本论文主要进行了以下工作： 1、泡沫镍现有情况调查及影响因素分析在现有生产设备及工艺条件的基础上，我们分析了影响泡沫镍抗拉强度的各种因素，发现： a．由于作为泡沫镍基体的HPB型聚氨酯泡沫的骨架结构不均匀，造成暗区有效骨架少，抗拉强度低。 b．HPB型聚氨酯泡沫的骨架结构不均匀对电力线的接受程度不同；并且现有沉积区过长，沉积区内电力线不均匀。两者共同影响造成面密度分布不均匀。 c．热处理还原温度过高，造成晶粒长大过度，抗拉强度降低。 2、工艺研究为了解决暗区有效骨架少的问题，我们通过在PVD阶段对聚氨酯泡沫进行定向改型，增加了单位纵向横截面积内有效骨架数量，使泡沫镍纵向抗拉强度得到提升。同时对极间距、沉积膜电阻、工作真空度和冷却系统等因素对定型效果的影响进行研究，制定出相应的工艺。通过降低电沉积沉积区尺寸及调整阳极的位置，可以使泡沫镍面密度更均匀。减小沉积区尺寸和采用倾斜式阳极都会使沉积区内电流分布更加均匀，减轻聚氨酯泡沫骨架结构带来的负面影响。但是减小沉积区尺寸和采用倾斜式阳极都会增加能耗，降低生产速度。研究发现泡沫镍晶粒长大主要发生在还原阶段，通过降低热处理时的还原温度或者加快热处理速度都可以减小泡沫镍晶粒尺寸，提高泡沫镍的抗拉强度。合理的控制各热处理参数可以保证各项性能合格的前提下提高泡沫镍的纵向抗强度。采用新的工艺组合，生产的常规面密度泡沫镍及低面密度泡沫镍，均达到纵向抗拉强度提高10%的目标。关键词：泡沫镍，纵向抗拉强度，PVD改型，面密度均匀性，热处理 "
其他摘要	" For its three-dimensional network structure, high porosity, large surface area, and uniform quality, nickel foam becomes ideal electrode substrate material of MH-Ni and Cd-Ni battery. But in recent years, nickel prices continued to run high with increasing demand for nickel. In order to reduce the cost of the battery, lower density nickel foam became the main direction of research and development. Low-density nickel foam with high longitudinal tensile strength became a key problem that must be solved to meet continuous cell production. This paper mainly described the following work: Survey of existing nickel foam process and analysis of influencing factors of process. On the basis of existing production equipment and process conditions, we analyzed the various factors influencing the tensile strength of nickel foam, and found that: As nickel foam substrate, HPB-type polyurethane foam skeleton structure is uneven for its bright and dark zone. Low long tensile strength is resulted from less skeleton in dark zone. Acceptance of the power lines is different on uneven HPB polyurethane foam skeletons; and distribution of power line area is uneven for long deposition area. The combined effects lead to the uneven distribution of surface density. Too big grains also decrease long tensile strength which is caused by high reduction of heat treatment temperature. Process research In order to solve the problem of less effective skeletons in the dark zone, polyurethane foams is directionally modified at PVD stage to increase the number of skeletons in the longitudinal cross-sectional area effectively, so that the longitudinal tensile strength of nickel foam is improved. The factors on the modified effects are researched which include anode-cathode distance, deposited film resistors, vacuum and cooling systems, thus the specification of process is determined. Surface density of nickel foam is more uniform by reducing the size of electro-deposition zone and adjusting the position of the anode. Reduction of the deposition area size and the use of tilt-type anode could make the current distribution more uniform in the deposition area, and reduce the negative effects which are caused by skeleton structure of polyurethane foams. However, reduction of the deposition area size and the use of tilt-type anode would increase energy consumption and reduce the production efficiency. It is found that grain growth occurres mainly at the recover stage. The grain sizes of nickel foams could be reduced by lowering heat treatment temperature or speeding up the rate of heat treatment, which improve the longitudinal tensile strength of nickel foam. Reasonable control of heat treatment parameters could ensure the properties of target and improve the longitudinal tensile strength of nickel foams. Combined with new technique, both normal and low-density nickel foam could reach the target that longitudinal tensile strength increase 10%. Key words: nickel foam, long tensile strength, PVD foam modified, uniform of surface density, heat treatment "
文献类型	学位论文
条目标识符	http://ir.imr.ac.cn/handle/321006/64561
专题	中国科学院金属研究所
推荐引用方式 GB/T 7714	刘伟华. 高强度泡沫镍生产工艺研究[D]. 北京. 中国科学院金属研究所,2012.