Synthesis of electrical discharge metal matrix composite coating through compacted semi-sintered electrode and its tribological studies

• Published in: Journal of the Brazilian Society of Mechanical Sciences and Engineering Vol. 41; no. 5; pp. 1 - 15
• Main Authors: Arun, Ilangovan, Yuvaraj, C., Selvarani, P., Senthilkumaar, J. S., Thamizhmanii, S., Muruganandam, P.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.05.2019; Springer Nature B.V
• Subjects: Alloying elements; Blowholes; Carbon; Coated electrodes; Coefficient of friction; Cracks; Electric discharges; Energy dispersive X ray spectroscopy; Engineering; Lubricants; Mechanical Engineering; Metal matrix composites; Metallurgy; Migration; Properties (attributes); Pyrolysis; Reduction; Scanning electron microscopy; Sintering; Substrates; Technical Paper; Tribology; Tungsten; Wear rate; Electrical discharge alloying; Coefficient of friction; Specific wear; Metal matrix composite; Material migration
• ISSN: 1678-5878; 1806-3691
• DOI: 10.1007/s40430-019-1718-7

Electric discharge coating is an alternative process for surface modification/alloying/coating requirements to improve mechanical and metallurgical properties of the materials. The high-pressure compacted electrode is made of the semi-sintered nickel and tungsten during the electric discharging process which influences the material migration towards substrate. In this proecess addtiton of pyrolysis carbon from dielectric togeather with the alloying elements and substrate material results in formation of metal matrix composite coating. It depended on the stabilization pressure of spark which increases the deposition rate of alloying materials and reduces the carbon, brittleness, cracks, voids, blowhole on the surface and made the layer to be desired metallurgical properties. Modified layer shows higher in hardness value of 1100 HV0.5 and reduction in specific wear to 0.082 × 10 −5  mm 3 /Nm compared with uncoated substrate material. Inclusion of the alloying material and reduction of the carbon percentage consequences in self-lubricant properties which alter the wear rate and coefficient of friction. Surfaces topography obtained during alloying, material migration and the mechanism have been characterized through scanning electron microscopy and energy-dispersive X-ray spectroscopy. The wear behaviour has been analysed by using pin-on-disc tribometer.