原 文： Magnesium alloy electric wheel hub
micro-arc oxidation production research
学生姓名 ： 陈孟丽 学号：1002130301
专 业 ： 机械设计制造及其自动化
院（系） ： 机电工程学院
2015年4月10日
Magnesium alloy electric wheel hub micro-arc oxidation production research
Most electric vehicles at home and abroad is configured to aluminum alloy wheel hub, its quality, energy saving, shock absorption, noise reduction and vehicle dynamics characteristics index is much lower than magnesium alloys. Magnesium alloy is 30% lighter than aluminum alloy, the damping effect is 30 times that of aluminum alloy. Replace the aluminum alloy with magnesium alloy wheel hub, driving the development of magnesium alloy material development and deep processing technology, to reduce electric vehicle weight and power consumption, energy conservation and environmental protection; To reduce vibration and noise; Improve ride comfort and electric vehicle dynamic characteristics such as objective (transportation quality each reduce 10%, energy consumption will be reduced 8% ~ 10%). But its corrosion resistance is poor, seriously limits the application. Commonly used chemical oxidation and anode oxidation formation of oxide film on magnesium alloy has certain protective effect, but its corrosion resistance, environmental friendliness, appearance is not satisfactory, be badly in need of the development of new surface treatment. In recent years, people trying to develop a var
冷光源uv机iety of new technologies, such as micro arc oxidation technology, the better
One Micro-arc oxidation mechanism
Micro-arc oxidation technology is a new surface treatment technology of green environmental protection, can grow in light metal surface in situ ceramic layer directly. Its technological characteristics, surface treatment, as well as the performance of the since the technology was invented by the favour of people, its mechanism is to light metals such as aluminum, magnesium, titanium and its alloy put in electrolyte aqueous solution as anode, using the method of electrochemical spark discharge spots on the surface of the material, the thermal chemistry, plasma chemistry and electrochemistry, under the joint action of metal oxide ceramic layers of a surface modification technology
Two research methods and technology
This topic in the research on magnesium alloy electric wheel hub, higher requirements on the toughness of the alloy, so choose AM60B, melt and initial temperature of 468 ℃, the
melting end temperature is 596 ℃, the liquidus temperature range of 165 ℃. The chemical composition as shown in table 1.
Table 1 AM60B alloy chemical composition (WB / %)
Al | Zn | Mn | Si | Cu | Ni | Fe | 杂质 | 余量 |
5.6～6.4 | ≤0.20 | 0.26～0.5 | ≤0.05 | ≤0.008 光电限位开关 | ≤0.001 | ≤0.004 | 0.02 | Mg |
| | | | 聚乙二醇辛基苯基醚 | | | | |
Because of the magnesium alloy electric wheel hub surface area is larger, general above 0.4 m2, require micro-arc oxidation power supply is bigger, this subject adopts the lanzhou university of technology institute of materials and development of MAO - 300 type nc micro-arc oxidation production device (figure 1) micro-arc oxidation on magnesium alloy wheel casting processing, its similar to ordinary anodic oxidation equipment, including special high-voltage power supply, micro-arc oxidation alkaline solution of electrolytic tank, mixing system, cooling system, workpiece with stainless steel plate for peer electrode.湿电除雾器
With micro-arc oxidation method in sodium silicate and sodium hydroxide electrolyte fluid system in the preparation of magnesium alloy wheel casting oxide ceramic membrane, the concrete technological process first set oxidation process parameters and the alkaline tank sodium silicate solution, the cleaning after micro-arc oxidation of magnesium alloy wheel casting into cell 15 ~ 20 min, clean with clear water tank 2 ~ 4 min, add hot water in hot water (80 ℃, 10 ~ 15 min), closed, then cool in the cold water tank 2 min, hoisted out drainage, drying, examine the hub. After micro-arc oxidation treatment must be closed by hot water, formed by micro-arc oxidation discharge holes so the distribution of the channel and the surrounding a large number of micro cracks will be closed, prevent oxygen to cause oxidation. After completion of micro-arc oxidation, from after micro-arc oxidation on magnesium alloy wheel casting intercept film sample were analyzed, and to facilitate test analysis, request samples made of circular plate, so the sample interception location choice among wheels, most is shown in figure 2. Using scanning electron microscope analysis of oxide film
Figure 1 MAO - 300 type nc micro-arc oxidation power supply电阻线
Figure 2 after micro-arc oxidation magnesium alloy wheel hub casting and interception of
membrane layer analysis sample
彩灯控制器Three micro-arc oxidation process parameters on the quality of the film
Based on the research of the sample and analysis of micro-arc oxidation technology is, in fact, the substrate magnesium magnesium oxide. Figure 3 for the dimension of samples before and after oxidation appearance schematic simulation, which is suitable for ceramic oxide film a outward growth, namely the increase of size part, b is the depth of the internal oxidation to the matrix, a and b interface for initial sample surface position, h for the total thickness of oxide film.
Figure 3 samples dimension changes before and after micro-arc oxidation diagram
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