【作者】 张琦；

【导师】 程旭东；

【作者基本信息】 武汉理工大学 ， 材料学， 2010， 硕士

【摘要】 金属的腐蚀行为会引起巨大的经济损失和资源消耗,同时也是导致设备失效、事故发生的原因之一,因此研究金属的腐蚀与防护具有重要的意义。阴极保护是防止或减缓金属腐蚀的行之有效的方法之一。本文选用锌镍合金作为低电极电位耐腐蚀合金材料,通过氧乙炔火焰进行喷涂得到阴极保护涂层对金属基体进行保护。针对锌、镍熔点相差大,难以互熔的特点,本文采用机械合金化制备锌镍合金,分析了工艺参数对机械合金化结果的影响并得到最优参数,同时本文对机械合金化机理进行了分析。采用氧乙炔火焰喷涂制备锌镍合金涂层,对涂层性能进行了分析。本文主要研究内容和结果如下：1：通过机械合金化工艺的设计和优化制备锌镍合金,并且进行锌镍金属机械合金化机理及过程的分析研究,对工艺参数进行正交对比试验,以球磨过后粉末物相为指标,得出球磨工艺较优的工艺参数及各工艺参数对球磨结果的影响规律。一般而言在锌镍机械合金化过程中,选取球磨转速为400r/min-500r／min,球磨时间为70-80h,球料比为10：1,以无水乙醇为球磨介质可以得到反应充分的锌镍合金粉末。长时间的球磨容易造成粉体过细、粉末易于氧化的缺点,因此应当采取适当的工艺来保护粉末的氧化。2.利用Miedema理论计算了合金的形成自由能,其中金属间化合物-8.07(KJ/mol)＞固溶体-6.02(KJ/mol)＞非晶态-5.47(KJ/mol),说明热力学条件下,三种合金都有可能产生。球磨过程中晶粒细化产生的界面能、机械研磨积累的晶格畸变能及反位缺陷能是形成金属间化合物的主要原因。3：用氧乙炔火焰对锌镍合金进行喷涂,得到物相为锌镍过饱和固溶体的合金涂层,该涂层电位为-0.32V,低于同等环境下不锈钢电位(-0.20V),具备低电极电位的特点,同时该涂层自腐蚀电流(1.556×10-4mA/cm-2)低于不锈钢自腐蚀电流(6.751×10-4mA/cm-2),说明该涂层具备低电极电位耐腐蚀特点,能够满足服役需要。经过强酸强碱以及盐的腐蚀,涂层表现出良好的耐腐蚀性。更多还原

【Abstract】 The corrosion behavior of metals poses enormous economic losses and consumption of resources to the social development. Meanwhile, it is also one of the sources leading to equipment failure and accidents. So the research of metal corrosion and protection is of great significance. Cathodic protection is an effective method to prevent or slow down the metal corrosion. This zinc-nickel alloy used as a low electrode potential corrosion-resistant alloys, carried out by oxyacetylene flame spraying protective coatings by cathode protection on the metal substrate.Allowing for there is huge difference between the melting point of zinc and nickel and those two kinds of metals are hard to solute with each other, the zinc-nickel alloy was prepared by mechanical alloying, and the affects of how processing parameters acts on mechanical alloying results were discussed and finally the optimal parameters were available in this paper. At the same time, this paper also has analyzed the mechanism of mechanical alloying. Prepared by using an oxyacetylene flame spraying zinc-nickel alloy coating, the coating performance was analyzed. The main content and the results of this paper are shown as follows:1:The preparation of zinc-nickel alloy was designed and optimized by mechanical alloying process to which the theoretical analysis was conducted. According to the process parameters of the effects of ball milling and the phase of the powder after ball milling, the orthogonal experiment was designed, and optimum process parameters and principle of those parameters affecting the process were obtained. In general, in the zinc-nickel alloying process, the milling speed was confined between 400r/min-500 r/min; the milling time was 70-80h; and the ball ratio was 10:1. And then with ethanol as milling media the full reacted zinc-nickel alloy powder can be obtained. A long-time ball milling is prone to the shortcomings of the powder’s being too small and easily oxidized. So the appropriate process should be adopted to keep the powder from oxidation.2. Miedema theory was applied to calculate the formation free energy of alloys ordered intermetallics-8.07 (KJ/mol)> solid solution-6.02 (KJ/mol)> amorphous -5.47 (KJ/mol). Milling process grain refinement of interfacial energy, mechanical grinding accumulation of lattice distortion energy and antisite defects can be the main reason for the formation of intermetallic compounds.3:Oxyacetylene flame was used to spray on zinc-nickel alloy and supersaturated solid solution of nickel alloy coating was obtained. The potential of the coating was-0.32V, lower than the potential of stainless steel (-0.20V) under the same condition, so the coating was of the characteristics of a low electrode potential. Meanwhile, the coating from corrosion current (1.556×10-4mA/cm-2) being lower than that of stainless steel from corrosion current (6.751×10-4mA/cm-2), it was showed that this coating was of low change electrode potential and corrosion-resistance, and can meet the service needs. After strong acid and alkali and salt corrosion, the coating showed good corrosion resistance.更多还原