Magnetic-aided electrospark deposition
- 6 Downloads
A new electrospark deposition method (ESD), which employs a magnetized electrode to which fine powder is attracted, is proposed and studied. Unlike the traditional ESD method which employs a solid bar electrode, the electrode tip of this latest development can be regarded as a “fluidized” head formed by an assembly of coating powders. With the powder-assembled head acting like a soft brush, the electrode can closely follow the surface contours of the workpiece. For this magnetic-aided electrospark deposition method (M-ESD), the spark discharge location and the contact condition are no longer dictated by the irregular surface asperities of the solid electrode, but instead, “soft” contacts, which are self-regulating, are established between the magnetized coating powders and the workpiece surface. The experimental results showed that M-ESD was a more stable process than the traditional ESD process; moreover, the deposition weight of the former was significantly higher than that of the latter. The discharge mechanisms of these two processes were found to be different: single discharge for ESD and multiple discharges for M-ESD. This was confirmed by the discharge images captured by a high-speed camera and was supported by the results of the simulation of the electrical fields of the electrodes in the traditional ESD and M-ESD processes.
KeywordsElectrospark deposition Magnetic Powder Discharge mechanism Electrical waveform
The work described in this paper was fully supported by a grant from the Research Grants Council of the Hong Kong Special Administrative Region, China (Project No. PolyU 152096/15E).
- 2.Lin D, Ucok I, Onal K (2014) Electrospark deposition process for oxidation resistant coating of cooling hole. U.S. patent 2014/0050938 A1Google Scholar
- 4.Champagne V, Pepi M, Edwards B (2006) Electrospark deposition for the repair of army main battle tank components. Army Research Laboratory, Maryland, USA, Report no. ARL-TR-3849Google Scholar
- 7.Hollis KJ (2010) Zirconium diffusion barrier coatings for uranium fuel used in nuclear reactors. Adv Mater Process 168(11):57–59Google Scholar
- 11.Reynolds JL, Holdren RL, Brown LE (2003) Electro-spark deposition. Adv Mater Process 161(3):35–37Google Scholar
- 13.Belik VD, Litvin RV, Kovalchenko MS, Rogozinskaya AA (2007) Effect of pulse duration and size of interelectrode interval on electrospark spraying. II. Effect of pulse duration and size of interelectrode interval on composition and mechanical properties of coatings. Powder Metall Met Ceram 46(1–2):95–99CrossRefGoogle Scholar
- 19.Xia H, Kunieda M, Nishiwaki N (1994) Research on removal amount difference between anode and cathode in EDM process. Int J Jpn S Prec Eng 28(59):31–40Google Scholar