The New Jersey Institute of Technology's
Electronic Theses & Dissertations Project

Title:	Microstructural investigation of surface coating developed by electro-spark deposition technology
Author:	Xu, Tianzong
View Online:	njit-etd1993-164 (xv, 131 pages ~ 4.4 MB pdf)
Department:	Department of Mechanical Engineering
Degree:	Master of Science
Program:	Mechanical Engineering
Document Type:	Thesis
Advisory Committee:	Dubrovsky, Roman (Committee chair) Levy, Nouri (Committee member) Chen, Rong-Yaw (Committee member)
Date:	1993-01
Keywords:	Surface hardening Coatings Microstructure Electrometallurgy
Availability:	Unrestricted
Abstract:	Electro-spark deposition (ESD) is a pulsed-spark micro-welding process using an electrode to apply a fused, metallurgically bonded coating with an extremely low heat input so as to eliminate thermal distortion or changes in metallurgical structure of the substrate. The deposited surface achieves an exceptionally fine-grained, homogeneous coating that may approach as amorphous structure which is believed to contribute to good wear and corrosion resistance. In this research, an optical image analysis system, scanning electron microscope with computerized energy dispersive spectrometer, microhardness testing system and computerized surfanalyzer were employed to investigate the microstructure and properties of achieved surface coatings. As the results of this work, a special sample preparation method was designed, and microstructure-composition-properties of the surface coatings were obtained, showing that good bonding of applied coating and substrate as well as desirable transition microstructure contributed by alloying and diffusion can be achieved by electro-spark deposition process.