CC BY
15iSHS 2019
Moscow, Russia
MULTILAYER TiNbC COATINGS PRODUCED BY A COMBINATION OF PULSED ARC EVAPORATION AND ELECTRO-SPARK DEPOSITION IN
VACUUM
O. S. Manakova*", K. A. Kuptsov", A. N. Sheveyko", D. V. Shtansky",
and D. A. Sidorenko"
aNational University of Science and Technology MISIS, Moscow, 119049 Russia
*e-mail: [email protected]
DOI: 10.24411/9999-0014A-2019-10094
Today, one of the promising ways to improve the performance of parts and components of various machines and mechanisms is to modify their surfaces. Protective coatings based on hard carbides, borides, nitrides, etc. are used to enhance mechanical properties, heat- and wear resistance. Developing surface with desired properties is possible not only by selecting the composition of the formed layers, but also by creating gradient and multilayer coatings [1].
Two-layer coatings based on double carbide (Ti, Nb)C were developed for the sequential treatment of the steel substrate by the combination of electric-spark deposition (ESD) and pulsed arc evaporation (PAE) methods. Composite dispersion-hardened materials based on (Ti, Nb)C carbide were used as electrode materials. To increase erosion of the electrodes and improve the quality of coatings, a metal binder based on Ni was introduced into the electrode material. In this work electrode materials based on Ti-Nb-C system with binder were produced by a combined force SHS-pressing technology. The electrode materials were heat treated in vacuum at a temperature of 900°C for 4 h [2].
Optimal regimes of surface treatment for each deposition method were established. Selection of the optimal regime of ESD layer deposition was conducted on the basis of kinetics of mass transfer, structure and properties studies. The criteria for selection of PAE layer deposition regimes were coatings growth rate and integrity of the electrodes.
It was found that the coatings with the best properties were formed in an argon atmosphere at a pressure of 0.3 Pa under optimal conditions.
The structure, phase and chemical composition of the obtained two-layer coatings were studied by SEM (Fig. 1), TEM, XRD, XPS, and Raman spectroscopy. The coatings were also characterized in terms of their mechanical and tribological properties. It was found that the main structural components of the ESD layer were carbide phases ((Ti, Nb)C and Fe2C) and intermetallic phases based on Fe, Ni, Co, Ti. The PAE layer contained mainly fcc-phase based on carbide (Ti, Nb)C with a strong texture in the (220) direction.
Fig. 1. The microstructure of the two-layer coatings based on double carbide (Ti, Nb)C.
XV International Symposium on Self-Propagating High-Temperature Synthesis
The thickness of the formed two-layer coating was 21 |m. Roughness did not exceed 3.0 |m. The two-layer coatings were successfully obtained by the ESD and PAE combined technology and were characterized by low friction coefficient in the range of 0.16-0.25 compared to the single layer ESD coatings characterized by high friction coefficient of 0.7-0.8.
1. Ph.V. Kiryukhantsev-Korneev, A.N. Sheveyko, N.V. Shvindina et al., Ceram. Int., 2018, vol. 44, pp. 7637.
2. O.S. Manakova, V.V. Kurbatkina, E.A. Levashov, Russ. J. Non-Ferr. Met., 2015, vol. 56, no. 4, pp. 486.
