Pre- and post-surface treatments using electron beam technology for load-related application of thermochemical and PVD hard coatings on soft substrate materials
Pre- and post-surface treatments using electron beam technology for load-related application of thermochemical and PVD hard coatings on soft substrate materials
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DOI：
10.1016/j.surfcoat.2019.07.084
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发表时间：
2019-10
影响因子：
5.4
通讯作者：
A. Buchwalder;R. Zenker
中科院分区：
文献类型：
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作者：
A. Buchwalder;R. Zenker
热化学处理（氮化、渗硼）和硬质涂层等表面处理具有特定的涂层特征和性能，在钢的磨损和腐蚀保护方面有着广泛的应用。然而，当将这些表面处理应用于较软的材料（例如铸铁和铝合金）时，在它们的可处理性和承载能力方面存在限制。硬化、重熔、合金化等）与上述治疗之一结合。在其他特征中，热EB表面处理的特征在于高加热和冷却速率，其促进了各种非平衡微观结构的产生，其表现出增加的硬度，并且对周围的基材具有最小的热效应。此外，层的厚度是一个或两个数量级高于那些产生的热化学处理或硬coating.Based上的综合结果，并使用铸铁和铝合金为例，研究表明，在何种程度上双重处理可以克服上述限制，以及如何摩擦学和/或腐蚀载荷行为的影响。双重表面处理后实现的属性配置文件强烈依赖于固有的微观结构和化学过程。这些复杂的工艺受到一系列因素的影响，例如在第一工艺步骤中产生的EB表面层的热稳定性、第二工艺的相应温度和时间段等。硬度测量、划痕测试、实现了使用不同法向载荷的无润滑销-盘磨损试验和动电位腐蚀试验，以便于表征单-和经热处理的层。
With their specific layer features and properties, surface treatments such as thermochemical treatment (nitriding, boriding) and hard coating cover a broad field of application in the wear and corrosion protection of steels. Limitations exist, however, when applying these surface treatments to softer materials, such as cast irons and aluminum alloys in terms of both their treatability and load-bearing capacity.This contribution deals with investigations into duplex surface treatments, where a pre- and post-electron beam (EB) surface treatment (e.g., hardening, remelting, alloying etc.) was combined with one of the above-mentioned treatments. Among other characteristics, the thermal EB surface treatments were characterized by high heating and cooling rates that facilitated the generation of a variety of non-equilibrium microstructures, which exhibited increased hardness and had minimal thermal effects on the surrounding base material. Furthermore, the layer thicknesses were one or two orders of magnitude higher than those generated by thermochemical treatment or hard coating.Based on the comprehensive results and using cast irons and Al alloys as examples, the study demonstrates the extent to which duplex treatments can overcome the aforementioned limitations, and how the tribological and/or corrosive load behavior is affected. The property profiles achieved after duplex surface treatment were strongly dependent on the inherent microstructural and chemical processes. These complex processes were influenced by a range of factors, such as the thermal stability of the EB surface layer generated in the first process step, the respective temperature and time period of the secondary process, etc.Hardness measurements, scratch tests, unlubricated pin-on-disc wear tests using different normal loads and potentiodynamic corrosion tests were realized to facilitate characterization of the different load behaviors of the single- and duplex-treated layers.