Electrodes for electro-spark alloying (ESA)
and thermoactive electro-spark
surface strengthening (TRESS) methods

Strengthening and restoration of rolls by a disk-electrode

Electro-spark alloying (ESA) is attracting much attention in preparing protective coatings. ESA provides some obvious advantages in comparison with other deposition methods such as low cost, high productivity, relative simplicity and compactness of equipment, ecological safety. This process has some other useful characteristics such as the possibility of local coating deposition and the absence of substrate heating. Elaboration of the method is connected with the development of new materials for electrodes by either the force SHS-compaction or SHS-extrusion technologies. TRESS is a new method which combines the ESA and SHS processes within the interelectrode space. It is based on the exothermal and chemical reactions in the interelectrode space initiated by pulse discharge energy. The reaction (synthesis) products are formed on both the charge electrode tip and the work piece surface. The energy evolved as a result of the chemical reaction is comparable or even exceeds the energy of the chemical discharge. Therefore the total energy of the TRESS-process is significantly higher than the energy typical for the well-known ESA process. Thus it is possible to increase the efficiency of the deposition process 2–3 times. Electrical discharge initiates the synthesis reaction which, depending on the mix composition, can proceeds both in the regime of guided burning and locally within spark gap between the consumable electrode (anode) and the substrate (cathode). TRESS results in a high adhesion between the coating and substrate because of partial fusion of the substrate surface. Thus, TRESS process is somewhat similar to micro welding.

	Complete set “Alier-Metall”
Blending electrodes for TRESS

Applications

The film and coating systems obtained could be used in car, oil-extracting, mining, agriculture, food, and air space industries, as well as mechanical engineering.

ESA and TRESS coatings: surface strengthening and restoration of dies using in car industry; working edges of forges, punches, dies, trimmers, as well as dies for isothermal pressing; cutting tools, saws, and drills; farm equipment; equipment for oil-extracting industry (gasket rings for joint pipes); joint parts in the rocket engines; refit of rolls.