共沉淀法制备纳米Al₂O₃弥散强化铜基复合材料的研究

【作者】 符学龙；

【导师】 戴起勋； 丁红燕；

【作者基本信息】 江苏大学 ， 材料学， 2007， 硕士

【摘要】 本论文研究了Al₂O₃陶瓷颗粒弥散增强铜基复合材料的制备技术及制备材料的组织和性能，并采用LS-800型激光粒度仪测试复合粉的二次粒径D₅₀和粒度分布，ARL／XTAR X射线衍射仪（XRD）进行复合体的物相分析，日立S-3000N型扫描电子显微镜（SEM）观察复合粉体的形貌以及磨痕，用Micro-XAM^TM型非接触式表面三维形貌仪测试磨损体积和三维形貌。改变共沉淀法溶液中的母液浓度，沉淀剂浓度，反应温度以及pH值，采用XRD、SEM和激光粒度仪等分析测试技术对共沉淀法制备的复合粉进行检测，结果表明：最佳工艺参数为反应温度55℃，pH值为7，CuSO₄浓度为0.095mol／L，NH₄Al（SO₄）₂浓度为1.67g／L，NH₄HCO₃浓度为1.52mol／L，得到的复合粉粒径在60nm左右。通过对还原后的粉体进行热压烧结的复合材料进行性能研究，测试结果显示：增加热压压力、升高热压温度和延长保温时间都可以提高复合材料致密度，其中热压压力最为显著，最佳烧结工艺是烧结温度为900℃，压力为24.5MPa，保温时间为2小时。利用球-面接触式摩擦磨损试验机研究了Al₂O₃颗粒增强铜基复合材料的干滑动磨损行为，铜基复合材料的摩擦磨损主要以粘着磨损为主，强化相的加入提高了基体的抗磨损性能；随着陶瓷颗粒含量的增加，铜基材料的耐磨损率性能出现先升高后下降的走势；提高摩擦磨损时的负载，复合材料的磨损体积损失将逐步升高。复合材料中强化相的增加会提高材料的硬度和耐磨损性能，但降低材料的电导率；复合材料具有好的致密度，提高材料的电导率，提高材料的耐磨损性能。最终选择Al₂O₃含量为2％的铜基复合材料为最佳，其相对密度为92.875％，电导率为44.2μΩ·cm，耐磨性能为纯铜的2.4倍，综合性能最佳。更多还原

【Abstract】 In the thesis, the preparation technology of nano-Al₂O₃-dispersed strengthening copper-based composites was investigated, including their structures and properties. The average size of composite powder and its distribution was analyzed by LS-800 Laser Particle Analyser and ARL/ XTAR X-Ray Diffraction; The composite structure and the appearance of powder and the wear-trace was observed by S-3000N Scanning Electron Microscope; the volume loss and 3D Microsope is tested by Micro-XAM^TM 3D Microsope respectively.The experiment scheme is that: change the maternal solution concentration, the precipitator concentration, the reaction temperature and pH, the compound powder produced by co-precipitation was analyzed by XRD, SEM and laser granular analyzer. The results showed that: the optimized reaction parameter was 55℃in 7pH with 0．095mol/L CuSO₄, 1．67g/L NH₄Al（SO₄） ₂ and 1．52mol/L NH₄HCO₃ concentration. The mean particle size of the composite powder obtained by the optimized process was about 60 nm.The nano-powder deoxided by hydrogen was then hot-pressed in order to achieve the composites with good properties, the results were as following: increase the hot pressure, improve the hot-press temperature and prolong the heat preservation time could all improve the relative density of the composites, especially the prominent effect of the hot pressure. So the optimized sintering processes were: the hot-pressed temperature was 900℃, the hot pressure was 24．5MPa, heating preservation time was 2h.Dry sliding wear behavior of Al₂O₃-dispersed strengthening copper-based composite was studied by using ball-on-surface test rig. The results showed that the friction behavior of composite was primary of adherence wear. The addition of strengthening phase improve the counter-abrasion properties of matrix, the counter-abrasion properties of copper-based composite were hoisted and then descended with the augment of porcelain content. The volume loss of composite was improved with the elevating load pressed on.The increase of the volume of ceramics will lead to increase wear-resistance and stress with the expense of decrease of the conductivity and thermal expansion of copper-based composites. The composites with good relative density will shorten the distances between grains, which will improve conductivity and wear-resistance and rupture intensity of the composites.The over-all properties of copper-based composite with Al₂O₃ 2wt% are considered to be the best, because its relative density is 92．875%, electrical conductivity is 44．2μΩ·cm, and its wear-resistance is 2．4 times of pure copper.更多还原