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Effects of operating conditions on the surface modification of steel using a coating method of closed-type electrical discharge

¡@¡@An electrical discharge coating method, which an isolated sleeve is used to form a closed space between the end surface of electrode and the workpiece so that the particles, the ions, and the pressure during the discharge process are concentrated on this space, is employed to increase the coating speed and the quality of the coating. The electrode for the cathode is made of brass, and the workpiece for the anode SKD11. They are immersed in kerosene containing W/C powder with the concentration of 50g/L. The time for the pulse-on is 25£gs and that for the pulse-off times 500£gs. The growing thickness and the quality of coating layer are investigated under the supply voltage of 50-400V, discharge coating time of 34-284s, and the gap distance of 50-300£gm.
¡@¡@Experimental results show that when the supply voltage is larger than 100V, the gap distance less than 150£gm and discharge coating time 142s, the area covered by the coating can achieve more than 90 percent of the total surface area. Moreover, the coating thickness increases with increasing gap distance and discharge coating time, but as the gap distance is larger than 150£gm, the coating thickness decreases with increasing gap distance.
¡@¡@For a special case, under the supply voltage of 200V, the gap distance of 100£gm and the discharge coating time of 142s, the coating thickness can achieve about 17£gm with little pore in the coating layer. The hardness of the coating layer can almost achieve the level of W/C hardness.

Identiferoai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0826109-222554
Date26 August 2009
CreatorsMa, Chia-nan
ContributorsRong-Tsong Lee, Jen-Fin Lin, Yuang-Cherng Chiou, Yeau-Ren Jeng
PublisherNSYSU
Source SetsNSYSU Electronic Thesis and Dissertation Archive
LanguageCholon
Detected LanguageEnglish
Typetext
Formatapplication/pdf
Sourcehttp://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0826109-222554
Rightsnot_available, Copyright information available at source archive

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