تاثير ساخارين بر خواص خوردگي و تريبوخوردگي پوشش هاي الكترولس نيكل-فسفر

چكيده انگليسي :

96 Effect of saccharin on corrosion and tribocorrosion properties of Electroless NiP coatings Amin Fayazi A Fayazi@ma iut ac ir Date of Submission January 22 2014 Department of Materials Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisors K Raeissi Associate Professor k raeissi@cc iut ac irA Saatchi Emeritus Professor saatchi@cc iut ac irAbstractNiP coatings were electrolessed on carbon steel AISI 1045 without saccharin and in presence of 10 and 20 g Lsaccharin in bath solution Elemental composition of coatings showed 11 2 wt W for NiP coating withoutsaccharin in bath solution and 10 7 and 10 6 wt W in presence of 10 and 20 g L saccharin in bath solutionrespectively The presence of 10 and 20 g L saccharin in bath solution caused to co deposition of 1 0 and 1 4 wt W sulphur respectively The scaning electron microscopy photographs exhibited the refining of nodules sizewith addition of saccharin to bath solution The structure of NiP coatings with and without saccharin in bathsolution were totally amorphous and with increasing dosage of saccharin to 10 and 20 g L saccharin in bathsolution the peak broadening of 111 and 220 reflecting planes taked place that indicate the grain refining The surface roughness coatings in presence of 10 and 20 g L saccharin were 0 060 and 0 057 m that indicatedthe roughness refining compared to the coating without saccharin in bath solution 0 078 m The microhardness measurement of coatings exhibited 454 Hv for NiP coting without saccharin and increasing of hardnessto 473 and 620 Hv in presence of 10 and 20 g L saccharin respectively The potentiodynamic polarization andEIS tests showed that addition of saccharin to bath solution had not a devastating effect on the corrosion currentdensity but Corrosion performance will weaken in the anodic region and corrosion resistant in the anodic regionseverely reduced caused to co deposition of sulphur The potentiostatic and EIS analysis in the anodic potentialindicated the weaken of protective layer in the presence of saccharin to plating bath Tribo corrosion test in theOCP potential on wear track NiP coating without saccharin showed the lowest potential drop during wear whilethis coating showed the most worn volume during abrasion and with increasing of saccharin the amount of wornvolume decreased probable caused to hardness improvement in this coating Tribo corrosion test in the anodicpolarization on wear track the best performance of coated NiP in the worn volume and increasing of currentdensity obtained from the bath containing 20 g Saccharin and probable caused to hardness improvement in thiscoating Trib corrosion test in the cathodic polarization on wear track minimal degradation of current densityand minimal worn volume is obtained from the bath containing 20 g L Saccharin and probable caused tohardness improvement in this coating The type of wear mechanism in all cases of tribo corrosion test wasabrasive wear and only a slight weight percent silica silicon carbide ball as an abrasive substance was presentin the wear track which explains the slight adhesive wear mechanisms Friction coefficient at open circuitpotential anodic and cathodic were calculated The results showed that increasing the saccharin caused toincreasing of hardness and reduction of adhesion between coating abrasive ball and the friction coefficient wasreduced The lowest coefficient of friction between different types of potential was cathodic potential and thepossible cause is adhesion loss in interfacial coating abrasive ball Keywords Electroless NiP coating Saccharin Microhardness Corrosion Tribocorrosion Potentiodynamic Potentiostat EIS Friction coefficient

فياضي، امين

تاثير ساخارين بر خواص خوردگي و تريبوخوردگي پوشش هاي الكترولس نيكل-فسفر

ميكروسختي , پتانسيوديناميك , پتانسيواستات , طيف سنجي امپدانس الكتروشيميايي , ضريب اصطكاك