A.E. Kudryashov

About the Method of Thermoreactive Electrospark Surface Strengthening

The method of Thermoreactive Electrospark Surface Strengthening (TRESS) is presented in this work. Thus the process of coating formation becomes a less energy consuming one as compared to the basic technology of the electrospark alloying. The additional heat of the chemical reaction of the synthesis final products formation on the substrate contribute to the increase of thickness and continuity of the coating, to the diminution of the inner tension due to the smoother concentration gradients through the coating thickness. The opportunities of TRESS method are exposed with the example of the FGM wear- and heat-resistant coating formation on the base of NiAl, TiAl. FGM diamond containing coatings production by the said method is presented. Optimal conditions and technological parameters for diamond containing coatings deposition is found. The masstransfer kinetics, the coating structure and properties were studied.

Prospects of Nanodispersive Powder Applications in Surface Engineering Technologies

General potentials of UDD (ultra dispersive diamond), NbC, WC, W, WC-Co, ZrO2, Al2O3, Si3N4, Co, nanosized powders in determining structure and properties of composite electrodes and coatings deposited by electrospark alloying (ESA) and thermoreactive electrospark surface strengthening (TRESS) techniques were considered. It was shown that an addition of refractory compound nanosized powder to the electrode material positively effects microstructure and tribological characteristic of ESA-coatings. Nanoparticles incorporated in the coating on grains boundaries serve as a lubricant for friction pairs. Wear resistant W-C-Co coatings with a friction coefficient below 0.15 were deposited by TRESS using nanopowders of Co and W. Nano- or microstructural coatings on the base of cemented carbides can be formed, depending on pulse discharge energy and frequency. Examples of beneficial industrial application of the coatings strengthened by nanosized particles were presented.

New Multifunctional FGM Coatings Produced Using ESA and TRESS Methods

The influence of nanodispersed complex additives (ZrO2, Al2O3, W, WC, WC-Co, NbC, Si3N4) to SHS electrode materials on the mass transfer, structure and properties of electrospark coatings has been considered dependent on variation of the energy regimes of processing. The influence of the pulse discharge energy on the structure, composition, and properties of TRESS coatings has been studied. The optimum energy regimes of depositing high-quality multifunctional graded ESA and TRESS coatings have been found. It has been shown that introduction of nanodispersed complexes into electrode materials promotes improvement of the properties of ESA coatings.