Application of galvanic iron-based compositions
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KROITORU, Dumitru, GURYANOV, G., SKLIFOS, S., BOBANOVA, Zh.. Application of galvanic iron-based compositions. In: Materials Science and Condensed Matter Physics, Ed. 7, 16-19 septembrie 2014, Chișinău. Chișinău, Republica Moldova: Institutul de Fizică Aplicată, 2014, Editia 7, p. 307.
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Materials Science and Condensed Matter Physics
Editia 7, 2014
Conferința "Materials Science and Condensed Matter Physics"
7, Chișinău, Moldova, 16-19 septembrie 2014

Application of galvanic iron-based compositions


Pag. 307-307

Kroitoru Dumitru1, Guryanov G.2, Sklifos S.3, Bobanova Zh.1
 
1 Institute of Applied Physics, Academy of Sciences of Moldova,
2 Bryansk State Agricultural Academy,
3 State Agrarian University of Moldova
 
Disponibil în IBN: 20 martie 2019


Rezumat

An increase in technical characteristics of a vehicle-tractor stock, namely, the rate of exploitation, productivity, etc., is connected with the growth of loads on the friction units and working parts. To provide for the growing necessities the materials with specific properties are required, which can guarantee reliability and long-term service of the vehicles. The materials that improve wear resistance of the surfaces of workpieces are the composite galvanic coatings (CGC) based on iron.  The iron-based CGC are obtained  from the electrolytes-suspensions (ES) which consist of the solutions of iron chloride (500--600 kg/m3) and particles of a disperse phase (DP) (40--100 kg/m3) at a current density of i = 30 A/dm2 on the cathode. As a substance of the second phase we used micropowders of carborundum (SiC), electro corund white (Al2O3), etc, of M7, M14, and M20 quality classes. The DP particles in the electrolyte were suspended by mechanical agitation.  During the CGC plating, hydrodynamic methods for controlling the compositions of the coatings were used (flow-stationary, centrifugal hydrodynamic field, etc.), which made it possible to vary the concentration of the DP particles in the wide range (0--30%).  Wear resistance was determined on a MVPD-1KPI friction machine, which models the conditions of the work of a cylinder-piston ring couple during the operation of the combustion engines. In the scheme of the testing, the wear of the upper fixed cylindrical specimen with a composite coating resulted from the friction of the latter against a flat chrome-plated surface of the lower specimen, which performed a reciprocal motion.  The studies performed showed high working efficiency of the iron-based CGC. Increase in the volume share of the DP in CGC in all cases lead to the growth of wear resistance of the compositions. The wear of the chrome-plated counterbody contacting the CGC varied insignificantly, correlating with the surface roughness. The least wear was exhibited by the specimens with M14 particles and content of 24--26%(vol.).  Treatment of the workpieces with the composite coatings was performed on polishing and honing machines. In particular, the study of the treatment of the cylinders with CGC was carried out under plant conditions on a honing machine using the hard-grained diamond bars to obtain the precision-and-efficiency standards of the treatment. The investigation proved the possibility of honing the cylinders with CGC using the hard-grained diamond bars. The correlation is established between the indices of precision and factors of the mechanical treatment, where the effects of the pressure of the bars and of the frequency of the hone rotation were found to be the greatest. With an increase in the hone rotation frequency and abrasive grain sizes of the bars the accuracy of the treatment of the cylinders with CGC grows, however, an increase in the pressure of the bars and in the number of the double strokes of the hone leads to a decrease of the accuracy of the treatment.   Galvanic compositions based on iron can be used in heavily loaded joints that work under conditions of the abrasive wear, high temperature and specific pressures.