Combined surface treatment for generation of multi functional surface by means of electron beam cladding (EBC) and thermochemical treatment (TCT) on an austenitic corrosion resistant steel (KomET)

耐腐蚀钢的特征在于优异的耐腐蚀性，但受到与耐磨性相关的相当大的限制。为消除这些不利因素而采取的许多治疗方法只取得了部分积极效果。所提交的项目是基于一种组合的表面处理与电子束熔覆（EBC）作为第一个工艺步骤和随后的离子氮碳共渗（PNC）。自己的初步研究表明，原则上可以提高硬度和耐磨性，并保持耐腐蚀性。该项目的目的是生成在腐蚀性介质中增加载荷条件下可用的层/基质化合物。以X6 CrNiMoTi 17 -12-2钢为例，首先要确定最佳的电子束参数，以生产单道次，特别是多道次的钴基EBC涂层，无裂纹和孔隙，以及完美的冶金连接。硬度和耐磨性应大大提高。耐腐蚀性至少应与基材的耐腐蚀性相近。这些研究的基础是一种选择的Co基添加剂，必须研究Cr和Fe含量对EBA涂层形成（微观结构）和混合程度的影响，即先前沉积的熔覆层的元素含量，特别是在多道EBA涂层中。结合EBC+PNC，应系统地研究冶金相容性和涂层配置（微观结构）对与致密材料相关的PNC层形成机制的影响，以及EBA涂层对随后生成的薄PNC层（膨胀奥氏体）的支撑作用。对EBA（EB/material相互作用）和PNC（Co基EBA涂层上N/C层的形成）过程进行了分析和解释。在选定的参考试件的基础上，研究了层/基体复合材料的载荷特性，即：e.将主要研究在不同应用特定载荷条件下发生的磨损和腐蚀机理。为此，应在不同载荷水平（法向力5-500 N）和/或不同温度（24-300 °C）下进行磨损试验（摩擦计），以及在不同酸性介质中进行腐蚀试验（在0.05 M酸性硫中进行动电位测量，在30%柠檬酸或20%酸性硫中进行长期试验）。在项目的结果中，应获得与项目相关的新的基础知识，并为工艺设计提供概括性的结论。

Corrosion resistant steels are distinguished by an excellent corrosion resistance, but are afflicted with considerably limitations related to wear resistance. Numerous treatments to eliminate these disadvantages led only partially to positive results. The submitted project is based on a combined surface treatment with an electron beam cladding (EBC) as first process step and a subsequent plasma nitrocarburizing (PNC). Own preliminary investigations showed that in principle it is possibly to raise hardness and wear resistance and to maintain the corrosion resistance at one. Aim of the project is to generate layer/matrix compounds useable under increased loading conditions in corrosive media. Using the example of steel X6CrNiMoTi17-12-2 initially there are to indentify optimum EB parameters to produce one- but especially multi-pass Co-based EBC coatings, free of cracks and pores, as well as a faultless metallurgical connection. Hardness and wear resistance should be improved considerably. The corrosion resistance at least should be nearly the same as that of base material. Basis for these investigations is one selected Co-base additive, which have to be investigated concerning the effect of Cr and Fe content on EBA coating formation (microstructure) and the degree of mix up , i.e. the element content of the prior deposited cladding layer, especially in the multi-pass EBA coating. In connection with the combination EBC+PNC, the metallurgical compatibility and the effect of coating configuration (microstructure) on the mechanisms of PNC layer formation in relation to a compact material as well as the supporting effect of the EBA coating for the subsequently generated thin PNC layer (expanded austenite) should be methodically investigated. The occurring processes during EBA (interaction EB/material) respectively PNC (N/C layer formation on Co-base EBA coating) will be fundamentally analyzed and interpreted. On the basis of selected reference specimens the load characteristic of the layer/matrix compounds, i. e. which wear and corrosion mechanisms occur in case of different application specific load conditions will be basically investigated. For that purpose should be carried out wear tests (Tribometer) on different load levels (normal force 5-500 N) and/or at different temperatures (24-300 °C) as well as corrosion tests in different acid media (potentiodynamic measurements in 0.05M acid sulfur, and long term tests in 30% citric acid or 20% acid sulfur). In result of the project should be obtained new basic knowledge about the project relevant combined surface treatment and created generalized conclusions for the process design.