ELECTRODEPOSITION OF Ni-Fe ALLOYS FROM SULFATE, SULFATE-CHLORIDE AND CHLORIDE BATHS

In an attempt to control the film composition, factors affecting the composition of Ni-Fe alloy deposits and their crystal structure have been analyzed as a function of bath composition, cathode current density, bath pH, temperature and an addition of citric acid. antimony electrode revealed that the deposition potential of Fe coincides with the potential where the abrupt increase of pH was observed. Ni-Fe alloy deposits have the layer structure and the thickness of each layer increased with an increase of the Fe content of the alloy deposits. Introduction Measurement of the pH of the cathode surface by using an Nickel-iron alloy coatings have many potential applications in industry as a functional coating because the alloy deposits have unique properties such as high hardness and stren th good ductility, brightness, sound corrosion resistance, etc coating are dependent on the composition and also on the structure of the deposits6-8). However, the deposition process of the Ni-Fe alloy is rather complex because of the anomalous codeposition of alloys. It is necessary, therefore, to obtain more electrochemical insight into the formation of Ni-Fe alloy films. mechanism of the anomalous codeposition of: Ni-Fe alloys from the mixed type sulfate-chloride bath as well as from the simple sulfate and chloride baths. The effect of plating variables on the codeposition of Ni-Fe alloys was also investigated. Experimental 7 s I . These physical and chemical properties of the Ni-Fe alloy In the present study, an attempt was made to elucidate the The composition of the bath used in this study is shown in Table 1. The cathode use: for the polarization measurement was a platinum disc (0 .75-4 cm ) plated with thin Ni-Fe alloy deposit. Cathode current efficiency was calculated from the total weight of the Ni-Fe alloy deposits and the quantity of the electricity passed during electrolysis. Measurement of the cathodic polarization curves was carried out by the potentiostatic and also galvanostatic methods by using a saturated calomel electrode (SCE) as a reference electrode. Partial 1 -