Proceedings of SerbiaTrib '13

Figure 6. Wear resistance by linear wear I h , [µm/m] atN = 600 cl. for each sampleFigure 7. Diagram of the comparative wear resistanceε i,0 = I i /I 0Table 3. Comparative wear resistance of the samples compared to the standard – electrochemical nickel coating withoutdiamond nanoparticles.Number of cyclesNComparative wear resistance, ε i,eε 1,0 ε 5,0 ε 10,0 ε 20,0N = 300 cl 1,22 0,76 1,60 3,68N = 600 cl 1,27 1,05 1,21 2,004. ANALYSIS OF THE RESULTSIt is found that the nickel yield decreases with theincrease of the diamond nanoparticles concentration inthe electrolyte. The Ni yield acquires its highest valuesof about 12.0 mg/cm 2 at diamond nanoparticlesconcentration C NDDS = 1g/l, current density I = 3 A/dm 2and process duration t = 10 min.It is found also that the microhardness of the coatingat concentration of the diamond nanoparticles C NDDS =1g/l is 4800 МPa or 2.5 times more than that of purenickel coating (1950 MPa) and 1.7 times more than thatof coating at concentration of the diamond nanoparticlesC NDDS = 5 g/l (2800МPа).The increase of the abrasive wear with the frictiondistance has nonlinear character and is different for thedifferent coatings. This relation is linear only for coatingderived from electrolyte with diamond nanoparticlesconcentration 5 %.The abrasive wear rate is not constant value in time.The only exception is coating obtained from electrolytewith diamond nanoparticles concentration 10 %.The presence of diamond nanoparticles in theelectrochemical nickel coatings leads to increase of thewear resistance. The wear resistance is increased withthe increase of the diamond nanoparticles content in theelectrolyte and the relation is of nonlinear character.Coating with 20 % content of diamond nanoparticlespossesses the highest wear resistance – 52,1.10 -6 at N =600 cycles. This wear resistance is 2 times higher thanthe wear resistance of coating without nanoparticles.Out of the studied coatings the coating containing 1% nanoparticles and deposited with current density 3A/dm 2 and process duration 10 minutes possesses thelowest wear resistance.Comparing the wear resistance of the coatings obtainedat equal diamond nanoparticles concentration 1 % andcurrent density 3 A/dm 2 , the coating obtained at processduration 15 minutes has 2 times higher wear resistance.REFERENCES[1] I. Petrov, P. Detkov, A. Drovosekov, M.V. Ivanov,T. Tyler, O. Shenderova, N.P.Voznekova, Y.P.Toporov, D. Schulz: Nickel galvanic coatings codepositedwith fractions of detonationnanodiamond, Diamond and related Materials 15,pp. 2035-2038, 2006.[2] M. Kandeva, Il. Peichev, N. Kostova, K. Stoichkov,Complex Study of Surface Layers and Coatings, Journalof the Balkan Tribological Association 17, 2011.[3] M. Kandeva, D. Karastoyanov and A. Andonova,Wear and tribotermal effects of nanostructurednickel chemical coatings, Applied Mechanics andMaterials Vols. 157-158, pp 960-963, 2012.[4] БДС 14289-77, Меthod of abrasion test by frictionagainst embedded abragant grain13 th International Conference on Tribology – Serbiatrib’13 45