Since the last two decades, many novel techniques have evolved from electro-discharge machining (EDM). Among them, surface modification is one of the rigorously growing technologies by which surface properties can be enhanced by providing a layer having a thickness up to some microns on the workpiece. Existence of tool material on the machined surface after EDM was observed previously. This attribute of EDM makes it a benchmark in surface modification technology. Surface modification in EDM can be done by using different types of electrodes like solid, powder metallurgy (P/M), brush type, etc. This phenomenon can also be acquired by suspending powder particles into dielectric media. However, P/M electrode gives superior results with less effort and also proves to be economical. In this paper, a review has been made on using P/M electrode in surface modification during EDM. The different types of electrodes for surface modification, development of P/M electrode, types of layers generated and surface roughness improvement are critically analyzed. Also, some scope for future works is suggested here.

中文翻译：

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使用粉末冶金电极通过放电加工进行表面改性：综述

近二十年来，许多新技术从电火花加工 (EDM) 发展而来。其中，表面改性是一种严格发展的技术，通过在工件上提供厚度可达几微米的层，可以增强表面性能。之前观察到电火花加工后加工表面上存在刀具材料。EDM 的这一特性使其成为表面改性技术的标杆。EDM 中的表面改性可以通过使用不同类型的电极来完成，如固体、粉末冶金 (P/M)、刷式等。这种现象也可以通过将粉末颗粒悬浮在介电介质中来获得。然而，P/M 电极以更少的努力提供了优异的结果，并且也被证明是经济的。在本文中，综述了电火花加工过程中P/M电极在表面改性中的应用。对用于表面改性的不同类型的电极、P/M电极的开发、生成的层类型和表面粗糙度的改善进行了批判性分析。此外，这里建议了未来工作的一些范围。