The structural characteristics of the trivalent chromium deposits and their interfacial behavior in the plating solution with and without polyethylene glycol molecules were observed by using various electrochemical me...The structural characteristics of the trivalent chromium deposits and their interfacial behavior in the plating solution with and without polyethylene glycol molecules were observed by using various electrochemical methods such as cyclic voltammetry,open circuit potential transition,electrochemical impedance spectroscopy,scanning electron microscopy and X-ray photoelectron spectrometry.It is shown that the polyethylene glycol molecules make the reductive current density lower in the trivalent chromium plating system and promote a hydrogen evolution reaction through their adsorption on the electrode surface.And the trivalent chromium layer formed from the polyethylene glycol-containing solution has somewhat higher density of cracks on its surface and results in a lower film resistance,lower polarization resistance,and higher capacitance in a corrosive atmosphere.It is also revealed that the formation of chromium carbide layer is facilitated in the presence of polyethylene glycol,which means easier electrochemical codeposition of chromium and carbon,not single chromium deposition.展开更多
The effect of cationic additive on Cr/nanodiamond plating was studied.Chromium plating was performed in Sargent bath.Morphology of deposit was observed by scanning electron microscope(SEM);microhardness by hardness te...The effect of cationic additive on Cr/nanodiamond plating was studied.Chromium plating was performed in Sargent bath.Morphology of deposit was observed by scanning electron microscope(SEM);microhardness by hardness tester;wear rate by tribometer;amount of diamond in deposit by combustion method and passivity by potentiodynamic scan.Experimental results show that in the presence of cobalt cation,the amount of nanodiamond particle in the deposit is increased.With increasing diamond particle amount,the metallurgical,mechanical and electrochemical properties of Cr/nanodiamond deposit are improved.However,this improvement seems to be constrained.In the presence of 10 g/L of nanodiamond powder and 2.5 g/L of cobalt cation in the bath,the amount of diamond particle in deposit is increased by 4 times;and wear rate of Cr-Co/nanodiamond deposit is decreased by 2-3 times as compared with pure Cr/deposit.The passive current of Cr-Co/nanodiamond composite deposit is decreased from 18 to 8 μA.The morphology of Cr/nanodiamond is smooth remarkably in the presence of cobalt cation.展开更多
文摘The structural characteristics of the trivalent chromium deposits and their interfacial behavior in the plating solution with and without polyethylene glycol molecules were observed by using various electrochemical methods such as cyclic voltammetry,open circuit potential transition,electrochemical impedance spectroscopy,scanning electron microscopy and X-ray photoelectron spectrometry.It is shown that the polyethylene glycol molecules make the reductive current density lower in the trivalent chromium plating system and promote a hydrogen evolution reaction through their adsorption on the electrode surface.And the trivalent chromium layer formed from the polyethylene glycol-containing solution has somewhat higher density of cracks on its surface and results in a lower film resistance,lower polarization resistance,and higher capacitance in a corrosive atmosphere.It is also revealed that the formation of chromium carbide layer is facilitated in the presence of polyethylene glycol,which means easier electrochemical codeposition of chromium and carbon,not single chromium deposition.
基金funded by KIMM' Project and KOFST (Brain Pool Program)
文摘The effect of cationic additive on Cr/nanodiamond plating was studied.Chromium plating was performed in Sargent bath.Morphology of deposit was observed by scanning electron microscope(SEM);microhardness by hardness tester;wear rate by tribometer;amount of diamond in deposit by combustion method and passivity by potentiodynamic scan.Experimental results show that in the presence of cobalt cation,the amount of nanodiamond particle in the deposit is increased.With increasing diamond particle amount,the metallurgical,mechanical and electrochemical properties of Cr/nanodiamond deposit are improved.However,this improvement seems to be constrained.In the presence of 10 g/L of nanodiamond powder and 2.5 g/L of cobalt cation in the bath,the amount of diamond particle in deposit is increased by 4 times;and wear rate of Cr-Co/nanodiamond deposit is decreased by 2-3 times as compared with pure Cr/deposit.The passive current of Cr-Co/nanodiamond composite deposit is decreased from 18 to 8 μA.The morphology of Cr/nanodiamond is smooth remarkably in the presence of cobalt cation.
