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  • 铝压铸铸件四种表面处理方法
  • 本站编辑:杭州达跃机械有限公司发布日期:2020-01-02 21:22 浏览次数:
  • 铸铝技术在现代机械、工业行业运用十分之广泛,铝压铸工艺是常见的铸铝制造方法之一。在工艺制作过程中会遇到一些问题,今天给大家介绍下铝压铸铸件的表面处理方法。
     
    1、铝材磷化
     
    通过采用SEM, XRD、电位一时间曲线、膜重变化等方法详细研究了促进剂、氟化物、Mn2+, Ni2+, Zn2+, PO4;和Fe2+等对铝材磷化过程的影响。研究表明:硝酸胍具有水溶性好,用量低,快速成膜的特点,是铝材磷化的有效促进剂:氟化物可促进成膜,增加膜重,细化晶粒;Mn2+, Ni2+能明显细化晶粒,使磷化膜均匀、致密并可以改善磷化膜外观;Zn2+浓度较低时,不能成膜或成膜差,随着Zn2+浓度增加,膜重增加;PO4含量对磷化膜重影响较大,提高PO4。含量使磷化膜重增加。
     
    2、铝的碱性电解抛光工艺
     
    进行了碱性抛光溶液体系的研究,比较了缓蚀剂、粘度剂等对抛光效果的影响,成功获得了抛光效果很好的碱性溶液体系,并首次得到了能降低操作温度、延长溶液使用寿命、同时还能改善抛光效果的添加剂。实验结果表明:在NaOH溶液中加入适当添加剂能产生好的抛光效果。 探索性实验还发现:用葡萄糖的NaOH溶液在某些条件下进行直流恒压电解抛光后,铝材表面反射率可以达到90%,但由于实验还存在不稳定因素,有待进一步研究。探索了采用直流脉冲电解抛光法在碱性条件下抛光铝材的可行性,结果表明:采用脉冲电解抛光法可以达到直流恒压电解抛光的整平效果,但其整平速度较慢。
     
     
    3、铝及铝合金环保型化学抛光
     
    确定开发以磷酸一硫酸为基液的环保型化学抛光新技术,该技术要实现NOx的零排放且克服以往类似技术存在的质量缺陷。新技术的关键是在基液中添加一些具有特殊作用的化合物来替代硝酸。为此首先需要对铝的三酸化学抛光过程进行分析,尤其要重点研究硝酸的作用。硝酸在铝化学抛光中的主要作用是抑制点腐蚀,提高抛光亮度。结合在单纯磷酸一硫酸中的化学抛光试验,认为在磷酸一硫酸中添加的特殊物质应能够抑制点腐蚀、减缓全面腐蚀,同时必须具有较好的整平和光亮效果
     
    4、铝及其合金的电化学表面强化处理
     
    铝及其合金在中性体系中阳极氧化沉积形成类陶瓷非晶态复合转 化膜的工艺、性能、形貌、成分和结构,初步探讨了膜层的成膜过程和机理。 工艺研究结果表明,在Na_2WO_4中性混合体系中,控制成膜促进剂浓度为2.5~3.0g/l, 络合成膜剂浓度为1.5~3.0g/l,Na_2WO_4浓度为0.5~0.8g/l,峰值电流密度为6~12A/dm~2, 弱搅拌,可以获得完整均匀、光泽性好的灰色系列无机非金属膜层。该膜层厚度为 5~10μm,显微硬度为300~540HV,耐蚀性优异。该中性体系对铝合金有较好的适应性, 防锈铝、锻铝等多种系列铝合金上都能较好地成膜。Aluminum casting technology is widely used in modern machinery and industry. Aluminum die casting technology is one of the common manufacturing methods of aluminum casting. In the process of production, there will be some problems. Today, I will introduce the surface treatment method of aluminum die casting.
     
    1. Aluminum phosphating
    The effects of accelerants, fluorides, Mn2 +, Ni2 +, Zn2 +, PO4, and Fe2 + on the phosphating process of aluminum were studied in detail by means of SEM, XRD, potential time curve and film weight change. The results show that guanidine nitrate has the characteristics of good water solubility, low dosage and rapid film formation, which is an effective promoter for aluminum phosphating: fluoride can promote film formation, increase film weight and refine grains; Mn2 +, Ni2 + can obviously refine grains, make phosphating film uniform, dense and improve the appearance of phosphating film; when Zn2 + concentration is low, it can not form film or poor film formation, with the increase of Zn2 + concentration, the film weight increases; PO The content of PO4 has a great influence on the weight of phosphating film, and PO4 is increased. The weight of phosphating film increased with the content.
     
    2. Alkaline Electropolishing of aluminum
    The basic polishing solution system was studied, and the effects of corrosion inhibitor and viscosity agent on the polishing effect were compared. The basic polishing solution system with good polishing effect was successfully obtained, and the additives that can reduce the operating temperature, prolong the service life of the solution and improve the polishing effect were obtained for the first time. The experimental results show that good polishing effect can be obtained by adding proper additives into NaOH solution. It is also found that the reflectivity of aluminum surface can reach 90% after electropolishing with NaOH solution of glucose under certain conditions. However, due to the unstable factors in the experiment, further research is needed. The feasibility of polishing aluminum in alkaline condition by DC pulse electropolishing is explored. The results show that DC constant voltage electropolishing can achieve the leveling effect, but its leveling speed is slow.
     
    3. Environmental friendly chemical polishing of aluminum and aluminum alloy
     
    It is determined to develop a new environmentally friendly chemical polishing technology based on phosphoric acid and sulfuric acid. The technology should achieve zero NOx emission and overcome the quality defects of previous similar technologies. The key of the new technology is to add some compounds with special functions to the base solution to replace nitric acid. Therefore, it is necessary to analyze the chemical polishing process of aluminum, especially the role of nitric acid. The main function of nitric acid in the chemical polishing of aluminum is to restrain the spot corrosion and improve the brightness of polishing. Combined with the chemical polishing test in pure phosphoric acid and sulfuric acid, it is considered that the special substances added in phosphoric acid and sulfuric acid should be able to inhibit the spot corrosion and slow down the overall corrosion, at the same time, it must have a better leveling and bright effect
     
    4. Electrochemical surface strengthening of aluminum and its alloys
     
    The process, properties, morphology, composition and structure of ceramic like amorphous composite conversion film formed by anodizing of aluminum and its alloy in neutral system were discussed. The results show that in the neutral mixed system of nazhu2wo ﹤ 4, the concentration of film-forming promoter is 2.5-3.0g/l, the concentration of complexing agent is 1.5-3.0g/l, the concentration of nazhu2wo ﹤ 4 is 0.5-0.8g/l, the peak current density is 6-12a / DM ~ 2, and the gray series inorganic non-metallic films with good luster can be obtained by weak stirring. The thickness of the film is 5-10 μ m, the microhardness is 300-540hv, and the corrosion resistance is excellent. The neutral system has good adaptability to aluminum alloy, and film can be formed on various series of aluminum alloy such as antirust aluminum and forged aluminum.