微弧氧化工艺在复杂铝合金工件上的应用研究

【作者】 石杰；

【导师】 贺子凯；

【作者基本信息】 昆明理工大学 ， 有色金属冶金， 2004， 硕士

【摘要】 微弧氧化是一种在阀金属表面原位生长陶瓷膜的新技术。本文在分析大量文献的基础上，对微弧氧化技术的发展概况及应用领域进行了概括，同时还对微弧氧化陶瓷膜层的性能、成膜机理及相关理论进行了综述。在微弧氧化工艺参数研究部分，重点考察了初始电压、电流密度及氧化时间对膜层生长的影响。并通过对膜层生长规律的研究及膜层厚度、硬度的测试，确定最佳的微弧氧化工艺条件。实验研究表明，控制适当的初始电压，电流密度为50A／dm2，氧化时间为60min的条件下，对LY12铝合金进行微弧氧化处理，能在铝合金表面生成具有一定厚度、硬度较高的陶瓷膜层。复杂工件研究以具有复杂外表面的齿圈状工件和具有内表面的圆筒状工件为对象，重点考察了影响微弧氧化在复杂工件表面上成膜均匀性的因素，最终通过合理控制工艺参数、适当地放置阳极及加入辅助阴极的方法，在复杂工件上生成性能良好、表面均匀的陶瓷膜层。通过对膜层的表面形貌的扫描电镜分析，指出在不同初始电压下，膜层形貌的差异，并结合微弧氧化机理加以分析。通过对膜层的XRD分析可知，膜层主要由不同晶型的Al2O3组成。其中α-Al2O3、 γ-Al2O3两相的生成是由熔融Al2O3快速冷凝的结果；膜层中出现δ-Al2O3相及其生成机理有待更多的实验进一步证实。更多还原

【Abstract】 Microarc oxidation (MAO) is a new technique, which can in-situ form a ceramic film on the surface of valve metal. On the base of studying lots of literature, Progress and application of MAO is summarized as well as the mechanism of the form of MAO ceramic film. Performance of MAO ceramic film and correlative theories are also reviewed.In the part of research of the technic parameter, the effect of initialization voltage, current density and oxidation time on the growth of MAO ceramic film is discussed. The best MAO process conditions are found by the research of the law of film growth, its thickness and hardness. The research show that ceramic film of certain thickness and high hardness on the surface of LY12 aluminium alloy can achieved by MAO under the conditions of proper initialization voltage, current density 50A/dm2, oxidation time 60min.The researches of complex workpiece focus on the gearwheels that contain complex exterior surfaces and the cylindrical objects that contain interior surfaces. Factors that can affect the uniformity of ceramic film on the surface of complex workpiece are studied. By the control of technic parameter, placing anode workpiece properly and puting assistant cathode, uniform ceramic film of good propertis can be formed on the surface of complex workpiece.By SEM, difference in surface morphologis of ceramic film is studied under different initialization voltage. And the difference is analyzed by the mechanism of form of MAO.The phase structures of ceramic film are analyzed by XRD. The results show ceramic film is made up of different kinds of A2O3. And the growth of a - Al2O3, y-Al2O3 is the results of rapid condensation of melt A2O3. Al2O3 product and its mechanism need to be confirmed by more researches.更多还原