Mathematical Modeling of Roughness Changing of Hard Metal Coatings Obtained by Contactless Electrospark Deposition

Surface Topography and Roughness Parameters of Electrospark Coatings on Titanium and Nickel Alloys

“…With an increase in the pulse energy, an increase in the diameter and time of the spark discharge occurs, as a result of which the erosion of the electrodes increases. The depth and size of the craters of the solidified material on the cathode grows and, as a result, the roughness increases [6][7][8][9][14][15]. In the ESD of the samples with initial roughness Ra=1.67, 2.5 and 3 μm, the roughness Ra of the coatings of all used electrodes at pulse energy up to 0.03 J is close to that of the initial titanium surface (Fig.…”

“…It is known [6][7][8][9][15][16][17][18][19][20][21][22][23][24][25] that the increase in energy leads to an increase in the thickness, hardness and amount of wear-resistant phases in the coatings, which creates prerequisites for increased wear resistance of the coated surfaces. At the same time, however, the roughness and unevenness of the coatings increases.…”

“…Up to certain limits, which are different for different specific cases, this increase is compensated by the high microhardness, the higher content of wear-resistant phases, the greater thickness and the fine-grained structure of the coatings [8,15,[17][18][19]21,25]. After these limits, the higher roughness begins to adversely affect the layered surfaces' tribological properties and reduce the lamination effect.…”

“…At present, the improvement of the surface properties of titanium alloys is carried out mainly by the methods of surface modification and application of wearresistant coatings [4,5]. Among these methods, the lightest, cheapest, most affordable and most versatile is electric spark deposition ESD [6][7][8]. The ESD surface layer changes the friction conditions in two main directions: a change of surface composition, the structure, and the surface microgeometry change.…”

“…The ESD surface layer changes the friction conditions in two main directions: a change of surface composition, the structure, and the surface microgeometry change. It is known that most often after ESD the roughness of the coatings is higher than that of the base and the relatively high roughness of ESD coatings adversely affects the wear resistance of coated products [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25].…”