Structural and Phase Elemental Distribution in Pulsed Plasma Coating Deposited with Cemented Carbide Cathode

Authors V.G. Efremenko1 , Yu.G. Chabak1 , K. Shimizu2, T.V. Pastukhova1 , N. Espallargas3, V.I. Fedun1 , V.I. Zurnadzhy1

1Priazovskyi State Technical University, 7, Universitetskaia St., 87555 Mariupol, Ukraine

2Muroran Institute of Technology, 27-1, Mizumoto-Cho, 050-8585 Muroran-city, Japan

3Norwegian University of Science and Technology, 7491 Trondheim, Norway

Issue Volume 12, Year 2020, Number 3
Dates Received 20 February 2020; revised manuscript received 15 June 2020; published online 25 June 2020
Citation V.G. Efremenko, Yu.G. Chabak, K. Shimizu, et al., J. Nano- Electron. Phys. 12 No 3, 03039 (2020)
PACS Number(s) 52.77. – j, 62.20.Qp, 61.66.Dk, 64.70.Kb
Keywords Pulsed-plasma deposition, Coating (35) , Cemented carbide, Microstructure (21) .

The object of this work is to study microstructural features of the coating obtained by pulsed-plasma deposition using cemented carbide WC-TiC-Со as an eroded electrode. The coating was deposited employing an electro-thermal axial plasma accelerator involving a pulse arc discharge with the power reached 20 MW. Cemented carbide (an alloy of T15K6 grade) was used as a tip of the cathode to be eroded under the discharge. The substrate material was low-alloyed structural steel 75Mn1. The investigations included scanning electron microscopy observation (Quanta FEG 650 FEI, Ultra-55 Carl Zeiss), energy-dispersive X-ray spectroscopy (JED-2300, JEOL) and microhardness measurement (FM-300, Future-Tech Corp.) under the load of 20 g. It was shown that after 10 plasma impulses the coating of 95-125 (m thick was obtained tightly adjusted to the modified substrate layer. The coating consisted of high-carbon martensite or martensite/retained austenite matrix with a microhardness of 415-977 HV (mean value of 707 ± 113 HV) and of randomly distributed 2.1 vol. % globular carbides (W,M)C and (Ti,M)C of 0.2-8.5 (m diameter. EDS study revealed that the carbides were alloyed with tungsten and titanium both. It allowed to conclude that carbides were not transferred by plasma flux but they crystallized in situ from the melt deposited on the substrate surface. The contribution of cemented carbide to the coating formation was limited by 17 % which was explained by low cemented carbide erosion caused by the high temperature of carbides WC and TiC melting. The coating was mostly composed of the product of the erosion of a steel anode. The matrix was alloyed with the elements (W, Ti, Co, Cu), released from the cathode during its melting/evaporation under the high-current discharge.

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