This study considers some aspects of electrolytic plasma in the process of anodic carburising of steel, including the nature of the glow in a vapour gaseous envelope, its thickness under various hydrodynamic conditions; it also examines the formation patterns of a hardened layer after carburising along with quenching in the same electrolyte. The glow in a vapour gaseous envelope was examined with a spectrometer; its profile and thickness were determined by solving energy and mass balance equations in a pre-anode area. The structure of the carburised layer and hardness distribution were explored with an optical microscope and a microhardness tester. Carbon concentration in the carburised layer was determined by means of optical emission spectroscopy. The investigation has revealed that the glow in a vapour gaseous envelope under carburising is a continuous emission from heated bodies—vapour gaseous phase and the sample without any electric discharges. It has been theoretically derived, that in laminar approximation the layer has maximal thickness under certain hydrodynamic conditions. This conclusion has been confirmed by homogeneous distribution of current density throughout the surface of the sample during its carburising under condition of force hydrodynamics, i.e. the sample being flowed round with cooled electrolyte. Aerated stirring in electrolyte does not provide homogeneous current density distribution, which falls in vertical direction. Anodic carburising of steel in a glycerol electrolyte followed by quenching results in the formation of a martensitic layer up to 200 μm in thickness, within 5-min treatment, with maximal microhardness 1000 HV.

中文翻译：

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低碳钢阳极等离子电解渗碳的物理特性

本研究考虑了钢阳极渗碳过程中电解等离子体的某些方面，包括蒸汽气态包层中辉光的性质、其在各种流体动力学条件下的厚度；它还检查了在同一电解液中渗碳和淬火后硬化层的形成模式。用光谱仪检查蒸气气态外壳中的辉光；它的轮廓和厚度是通过求解预阳极区域的能量和质量平衡方程来确定的。用光学显微镜和显微硬度计研究渗碳层的结构和硬度分布。渗碳层中的碳浓度通过光学发射光谱法测定。调查表明，渗碳作用下的蒸汽气态外壳中的辉光是来自加热体的连续发射 - 蒸汽气相和样品，没有任何放电。理论上已经推导出，在层流近似中，层在某些流体动力学条件下具有最大厚度。该结论已通过在力流体力学条件下渗碳过程中样品表面的电流密度均匀分布得到证实，即样品在冷却的电解液中流动。电解液中的充气搅拌不能提供均匀的电流密度分布，电流密度分布在垂直方向。钢在甘油电解液中阳极渗碳，然后淬火会形成厚度达 200 μm 的马氏体层，