In this dissertation, an electrical discharge coating uses an isolated sleeve to form a closed space between the end surface of electrode and the work to deposit a thin film onto a substrate. The discharge occurs at the location where the two surfaces are closest and the dielectric fluid ionizes at this location to create a path for the discharge. Hence, this closed space is heated to extremely high temperature, so that a small portion of the work surface is suddenly melted with the particles in the dielectric fluid and then coated to increase its coating speed and quality. The electrode material is made of brass, the work material SKD11, and the dielectric fluid is kerosene with the WC powder concentration of 50g/L. The pulse-on and pulse-off times are 25 and 500£gs, respectively. The effects of supply voltage, electrical discharge coating time, electrical discharge gap, and powder added cycle on the coating characteristics are investigated.
According to the experimental results, the electrical discharge with isolated sleeve can achieve a complete coating layer onto the surface of work. The coating thickness increases with increasing electrical discharge coating time and gap as the supply voltage is larger than the threshold voltage of electrical discharge. At the supply voltage below 250V and the added powder cycle less than 10, the coating thickness increases with increasing supply voltage and cycle. The quality of coating layer is better at the low gap distance and the high supply voltage. The hardness of coating layer is about HV 1687 which is approximately 5 times of substrate hardness using micro-hardness test. The electrical discharge without isolated sleeve cannot achieve the above-mentioned advantages.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0910108-093041 |
| Date | 10 September 2008 |
| Creators | LIU, YEN-HSIAO |
| Contributors | Hsiao-Ming Chu, Lee, Rong-Tsong, Yuh-Ping Chang, Chiou, Yuang-Cherng |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | Cholon |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0910108-093041 |
| Rights | not_available, Copyright information available at source archive |
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