本文選題：AZ91D鎂合金 + 超聲場(chǎng)��； 參考：《江蘇大學(xué)》2017年碩士論文

【摘要】：鎂及其合金是目前工業(yè)應(yīng)用中最輕的金屬結(jié)構(gòu)材料,我國(guó)鎂資源豐富,儲(chǔ)量為世界第一,鎂合金產(chǎn)量和出口量也名列前茅,廣泛應(yīng)用于國(guó)防軍工、航空航天、汽車等領(lǐng)域。但鎂合金表面生成的氧化膜不致密,在溶液中不穩(wěn)定,耐腐蝕性能差,限制了其應(yīng)用。表面改性技術(shù)是改善鎂合金的耐腐蝕性能的重要手段�；瘜W(xué)鍍是目前發(fā)展最快也是應(yīng)用最廣的表面處理技術(shù)之一。本文在AZ91D鎂合金化學(xué)鍍過(guò)程中引入超聲場(chǎng),通過(guò)單因素試驗(yàn)法優(yōu)化預(yù)處理工藝參數(shù);通過(guò)正交試驗(yàn)法優(yōu)化超聲化學(xué)鍍工藝參數(shù);通過(guò)單因素試驗(yàn)法優(yōu)化熱處理工藝參數(shù);最后采用間隔取液法延長(zhǎng)鍍液壽命。借助掃描電子顯微鏡、X射線衍射儀、電化學(xué)工作站和摩擦磨損試驗(yàn)機(jī)等儀器對(duì)化學(xué)鍍層的表面形貌、成分、結(jié)構(gòu)、膜厚、耐蝕性、耐磨性、沉積速率、結(jié)合力等性能進(jìn)行系統(tǒng)研究。結(jié)果顯示,超聲場(chǎng)能顯著提升化學(xué)鍍沉積速率,改善預(yù)處理表面質(zhì)量,提升結(jié)合力,制備的化學(xué)鍍層厚度均勻、完整致密,沉積速率提升了0.2083μm/min。在本試驗(yàn)條件下其最佳預(yù)處理工藝參數(shù)是:酸洗時(shí)間30 s,活化時(shí)間10 min;最佳化學(xué)鍍工藝參數(shù)是:溫度85℃,時(shí)間60 min,超聲功率80 W,pH值6.0;最佳熱處理工藝為300℃×1 h。經(jīng)過(guò)超聲化學(xué)鍍處理后鎂合金的自腐蝕電位比基材正移了0.902 V,顯著提高了鎂合金的耐蝕性;超聲化學(xué)鍍處理后鍍層表面均勻、致密、平整,其摩擦系數(shù)由基材的0.23降低到0.14,顯著提升鎂合金的耐磨性。經(jīng)300℃×1 h熱處理處理后,試樣結(jié)合力比未經(jīng)熱處理試樣顯著提升近一倍,此時(shí)鍍層的硬度達(dá)到峰值為890 HV。老化性試驗(yàn)中,鍍液的壽命為4 h;利用間隔取液補(bǔ)充溶液法可以延長(zhǎng)鍍液的施鍍時(shí)間至9 h。
[Abstract]:Magnesium and its alloys are the lightest metal structural materials in industrial application at present. China is rich in magnesium resources, its reserves are the first in the world, and its output and export are among the highest in the world. It is widely used in the fields of national defense, aerospace, automobile and so on. However, the oxidation film formed on magnesium alloy surface is not dense, unstable in solution and poor corrosion resistance, which limits its application. Surface modification technology is an important means to improve corrosion resistance of magnesium alloys. Electroless plating is one of the most widely used surface treatment technologies. In this paper, ultrasonic field was introduced into the electroless plating process of AZ91D magnesium alloy. The pretreatment process parameters were optimized by single factor test method, the ultrasonic electroless plating process parameters were optimized by orthogonal test method, the heat treatment process parameters were optimized by single factor test method. In the end, the bath life is prolonged by the method of interval liquid extraction. The surface morphology, composition, structure, film thickness, corrosion resistance, wear resistance, deposition rate of the electroless coating were studied by means of scanning electron microscope (SEM), electrochemical workstation and friction and wear tester. The properties such as binding force were studied systematically. The results show that the deposition rate of electroless plating can be improved by ultrasonic field, the surface quality of pretreatment is improved, and the adhesion is enhanced. The thickness of the electroless coating is uniform and compact, and the deposition rate is increased by 0.2083 渭 m / min. The optimum pretreatment process parameters are as follows: pickling time 30 s, activation time 10 min, optimum electroless plating process parameters 85 鈩，

本文編號(hào)：2107707