By塔哈汗2022年4月13日
在这里，我们讨论应用于金属合金的电流沉积，以修复注射成型工具和铸造模具中的缺陷。
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什么是电铅的沉积？
电渣岩沉积（ESD）用于使用脉冲微焊接在小规模上精确修复高价值磨损的组件。电铅的沉积也被称为脉冲电极表面，脉冲融合表面，电渣合金合金，电剥落的韧性和火花硬化。在行业中，它用于修复注射成型工具和铸造模具中的缺陷。
ESD系统具有基于电容器的电源，该电源通过旋转电线消耗电极产生脉冲。这些脉冲在非常短的持续时间内具有高电流。消耗电极（阳极）的材料通过电火花沉积在工件（阴极）上。
ESD Applied to Metal Alloys
当电容器能量释放时，直流电流在电极的尖端和金属合金工件之间产生高温等离子体弧。该高温范围在8000至25000°C之间。等离子体弧电离阳极，然后将该熔融材料迅速转移到工件上。
This ionized anode is transferred onto the substrate through short pulses. The high-temperature arc consists of anode particles, thermal flux (heat jet), and plasma (developed by gases decomposition and nitrogen, oxygen, and carbon active atoms). The major portion of heat is carried by the heat jet and the plasma.
Since the pulses are short, the heat transfer via heat jet and other gases is minimal, and the only heat transfer to the substrate is through the small number of anode microparticles deposited on the substrate. Therefore, these pulses impart a small heat input to the substrate, which results in no modifications of its microstructure. This method can be more beneficial than fusion welding processes generally used to repair alloys that have poor heat affected zone properties (like low toughness, high hardness, liquation cracking).
此外，此过程有助于在底物和涂层之间建立牢固的冶金键。电极熔体和基本材料之间的微合同通过空气分解，碳酸盐，碳化物和氮化物启动血浆形成。亚博网站下载
放电参数
The deposition quality depends on specific discharge parameters such as pulse time, current, and voltage, which rely on the chemical and physical properties of device-electrode-based materials. Therefore, the parameters depend on the electrode deposition type, temperature dependence, flowability, electrical resistance, density, diffusivity, chemical reactivity of anode elements, thermal conductivity, and melting temperatures.
优点
There are several advantages associated with ESD applied to metal alloys. For instance, no special preparation of the surface of the workpiece is required. The deposited layer attains amorphous specific properties due to high solidification speed, and it may not need subsequent finishing. ESD can be easily applied to the complex part’s surface, allowing deposition in strictly indicated places. Both metal alloys and pure metals can be used as an electrode. ESD allows the use of hard fusible compounds and metallic ceramics for deposition.
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ESD应用于金属合金的另一个优点是，在沉积过程中，样品缺乏加热。此外，ESD通过消除涂层过程中的有毒非金属材料（如氰化物）的使用来提供无污染的程序。亚博网站下载此外，设备非常简单，添加材料app亚博体育的质量决定了与ESD相关的成本。亚博网站下载
ESD程序的另一个优点是，该材料的热密度非常低，这有助于维持基本材料的特性及其化学成分。ESD方法形成的薄层分为两个子层。内部扩散层具有基本材料和添加材料的最终特性，而表面或外部层具有强烈修改的结构。ESD还增加了小表面积的侵蚀和耐磨性。
限制
ESD是修复浅和小缺陷的理想选择。但是，由于该过程的缓慢，涂层的最大厚度为2mm，因此不适合大缺陷。
有时，底物的几何形状限制了涂层。对于ESD，电极和底物表面之间的接触是必要的，但是某些表面几何不允许这种接触。因此，涂层仅应用于相邻区域。
沉积层的特征受过程参数的控制，例如电极尖端的压力，底物各个区域的通行次数，温度，频率，火花持续时间，火花能量等，表面波状的表面波动率少于电极的直径可能导致涂层仅在峰上建造。一些沉积参数可能导致初始覆盖不足，从而使某些零件发现。随着弧线进入最接近的表面，只有高点才能继续通过连续的传球和层来积累。解决此问题的解决方案是通过合适的参数选择最佳的工作方式。
最近的研究
最近，已经进行了许多有关同时应用ESD与其他方法制造特定合金的研究。例如，在2021年，罗马尼亚布加勒斯特大学Politehnica的研究人员发表了一篇论文，调查了通过ESD沉积的突破性的高腐蚀涂层。
In this research, an alloy with high entropy was fabricated through the dust of Zr, Ti, Ta, Nb and Hf by mechanical alloying and spark plasma sintering. A thin layer was coated on a stainless steel sample through ESD. This coating had improved hardness compared to the substrate, and when they tested for corrosion resistance it showed a very low corrosion rate of 0.00024 mm/year.
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参考和进一步研究
Johnson, R. N. (2002). Alternative coatings for wear and corrosion: the electrospark deposition process. published in Proceedings, American Electroplaters and Surface Finishers Society.https://www.nmfrc.org/pdf/awk02/awk02d06.pdf
Manea, C. A., Sohaciu, M., Stefănoiu, R., Petrescu, M. I., Lungu, M. V., & Csaki, I. (2021). New HfNbTaTiZr High-Entropy Alloy Coatings Produced by Electro-spark Deposition with High Corrosion Resistance. Materials, 14(15), 4333.https://www.mdpi.com/1996-1944/14/15/4333
Twi-Global，什么是电气线路沉积（ESD）？[在线]可用：<https://www.twi-global.com/technical-knowledge/faqs/faq-what-is-electro-spark-deposition-esd>
Vizureanu，P.，Perju，M。和Nejneru，D。A. C.（2018）。金属合金上的高级电流沉积过程。在（ed。），高级表面工程研究中。intechopen。https://www.intechopen.com/chapters/62514
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