3699

3499

كارشناسي ارشد

شناسايي و روش ساخت مواد

اصفهان: دانشگاه صنعتي اصفهان، دانشكده مواد

1386

[هشت]، 112، [I]ص.: مصور، جدول، نمودار

ص. ع. به فارسي

احمد ساعتچي، كيوان رئيسي

محمدعلي گلعذار

14/7/86

محمدابراهيم بحرالعلوم، حسين ادريس

مهندسي مواد

ID3499

به فارسي و انگليسي: قابل رويت در نسخه ديجيتال

AbstractIn this study electrodeposition of nanocrystalline nickel coating using direct current wasperformed in Watts type bath The effect of current density on grain size texture andmorphology of the nanocrystalline nickel coating was investigated In addition usingelectrochemical impedance spectroscopy EIS adsorption phenomena at different currentdensities and its effect on nickel deposition mechanism have been studied The effect ofpH coating thickness and saccharin addition have been investigated too Results obtainedrevealed that at low current densities in modified Watts bath physisorbed atomichydrogen inhibits growth and therefore decrease the grain size Increasing the coatingthickness to 12 micron does not affect the coating texture Variation of pH did not haveany effect on grain size The domain at which hydrogen adsorption proceeds from nickelreduction was detected by getting derivate from charge transfer resistance againstpotential By increasing the current density the texture of coatings changed from 220 A atlow to 200 at medium and to 220 B at high current densities The grain size wasdecreased by saccharin addition However charge transfer resistance was increased bysaccharin additions which means that surface diffusion coefficient of adsorbed nickel ionson substrate surface was decreased and therefore nucleation rate was increased i e inhibited growth effect On the other hand the texture intensity at the presence ofsaccharin was weaker and consisted of two components of 111 and 200

احمد ساعتچي، كيوان رئيسي

محمدعلي گلعذار

محمدابراهيم بحرالعلوم، حسين ادريس