【摘要】：人類文明從石器時代、銅器時代、鐵器時代、工業(yè)時代以及信息時代一路走來,對于能源以及材料的利用方式也在逐漸改變。相比于其他材料,金屬材料具有優(yōu)異的加工性能與使用性能,使得金屬材料在如今林林總總的材料中依然有著不可替代的地位。但是金屬材料也有一定的局限性,例如容易在各種腐蝕介質(zhì)中發(fā)生腐蝕,硬度高的金屬材料其塑性、加工性較差等。金屬表面處理是一種提高材料表面質(zhì)量性能的重要手段。通過表面處理,使得金屬材料的表面具有良好的耐磨、耐蝕性能,同時保持基體的金屬特性,從而達(dá)到擴(kuò)大金屬材料應(yīng)用領(lǐng)域,提高構(gòu)件壽命,減少資源消耗的目的。碳化鎢顆粒由于其優(yōu)異的物理化學(xué)性能常被用于金屬表面處理。將碳化鎢顆粒應(yīng)用于金屬表面涂層的常用工藝有激光熔覆、熱噴涂、釬焊等方法。這些方法中都存在一些問題,如涂層不能與基體形成良好的冶金結(jié)合,涂層結(jié)合強(qiáng)度低、涂層中存在較大的殘余應(yīng)力等。本文探索研究了采用真空熔覆法制備碳化鎢涂層的工藝,并成功應(yīng)用于螺桿鉆具徑向軸承套的表面。論文主要工作如下:(1)柔性金屬布成型工藝研究。制備柔性金屬布是真空熔覆方法有別于激光熔覆、熱噴涂的特點之一。通過將粉末狀增強(qiáng)相顆粒制備成金屬布,一方面提高了原材料利用率,另一方面增加了對增強(qiáng)相的包覆能力,使得真空熔覆技術(shù)可以應(yīng)用于工件的內(nèi)表面、外表面以及其它異形面。通過對比Ni60、WC粉末含量配比以及軋制參數(shù)對金屬布性能的影響,結(jié)果表明在Ni含量在40~50wt.%,軋制速率為2m/min,單次壓下量50%,20-30℃下可以制備出厚度均勻、組織致密、性能良好的柔性金屬布。(2)真空燒結(jié)工藝研究。真空熔覆工藝主要解決涂層如何與基體材料形成冶金結(jié)合的問題。真空燒結(jié)過程包括兩個階段:在第一階段燒結(jié)溫度550℃,可以使金屬布中的有機(jī)粘結(jié)劑完全揮發(fā);第二階段燒結(jié)溫度1150℃,保證Ni60粉末熔化使涂層粉末顆粒具有一定的流動性,并使熔體狀的Ni60包覆WC顆粒對基體形成良好的包覆。(3)涂層性能評價。主要對涂層結(jié)合強(qiáng)度、磨損性能、腐蝕性能三個方面進(jìn)行測試分析。通過制備不同的試樣分別測試了涂層界面的剪切結(jié)合強(qiáng)度、拉伸結(jié)合強(qiáng)度。結(jié)果表明涂層平均剪切結(jié)合強(qiáng)度可達(dá)151MPa,平均拉伸結(jié)合強(qiáng)度可達(dá)200MPa。涂層的耐磨性能主要依據(jù)環(huán)塊摩擦磨損試驗進(jìn)行評價,對磨材料為整體淬火45鋼。結(jié)果表明涂層耐磨性比45鋼提高了14倍。通過極化曲線表征了涂層的耐腐蝕性能,結(jié)果表明涂層自腐蝕電位為-588m V,自腐蝕電流密度為2.7μA/cm2,涂層耐腐蝕性能介于45鋼與304不銹鋼之間,適用于一般耐腐蝕環(huán)境中。
[Abstract]:From the Stone Age, the Bronze Age, the Iron Age, the Industrial Age and the Information Age, the use of energy and materials is gradually changing. Compared with other materials, metal materials have excellent processability and use performance, which makes metal materials still have irreplaceable position in all kinds of materials. However, metal materials also have some limitations, such as corrosion in various corrosive media, high hardness of metal materials plastic, poor workability and so on. Metal surface treatment is an important means to improve the surface quality of materials. Through surface treatment, the surface of metal materials has good wear resistance and corrosion resistance, while maintaining the metal properties of the matrix, thus expanding the application field of metal materials, increasing the life of components and reducing the consumption of resources. Tungsten carbide particles are often used in metal surface treatment because of their excellent physical and chemical properties. Laser cladding, thermal spraying and brazing are commonly used to apply tungsten carbide particles to metal surface coating. There are some problems in these methods, such as the coating can not form a good metallurgical bond with the substrate, the bonding strength of the coating is low, and there are large residual stresses in the coating. The preparation process of tungsten carbide coating by vacuum cladding has been studied and successfully applied to the surface of radial bearing sleeve of screw drill tool. The main work of this paper is as follows: (1) Research on forming process of flexible metal cloth. The preparation of flexible metal cloth is one of the characteristics of vacuum cladding, which is different from laser cladding and thermal spraying. On the one hand, the utilization ratio of raw materials is improved, and the coating ability of the reinforcing phase is increased, which makes vacuum cladding technology applicable to the inner surface of workpiece. External surfaces and other special-shaped surfaces. By comparing the effect of Ni60,WC powder content ratio and rolling parameters on the properties of metal cloth, the results show that when the content of Ni is 40 ~ 50wt., the rolling rate is 2 m / min, the single reduction amount is 50 ~ 30 鈩，

本文編號：2290560