Electrodeposition Of Zn-fe-re Ternary Alloy Process

The author studies the technologies and principles of the sulfate system and electrodeposition Zn-Fe-Re coatings of ternary alloy in this paper ,and how to the electrodepositrion the Zn-Fe-Re coatings of ternary alloy by choosing Lacl3 under the sulfate system. The main processes are as fallows:Through the perpendicularity experiment of 250mlHull's trough experiment and 150ml rectangle alveus experiment, the electrodeposition technology was confirmed by using the Rare earth salt in the sulfate system as an addition to change the functions of Zn-Fe alloy coatings. The technology conditions should in include:FeSO4.7H2O 80~120g/L, ZnSO4.7H2O 30~50g/L, Ce3(SO4)2 0.6-1. 5g/L, (NH4)2SO4 50~80g/L, C6H8O7.H2O 10~20g/L,H3BO3 5~15g/L, l~3g/L of ascorbic acid, proper addition, PH is 2 to 4,10minutes of electroplate time,Dk= 2~4A/dm2 of electric current density and 20~30癈 temperature of electroplating solution.On the basis of the sulfate system and by consulting a lot of literatures, the author confirms the electrodepositrion technology of Zn-Fe-La coatings of ternary alloy, which is by using Hull trough experiment and rectangle alveus experiment to choose the bright area of the coatings. The technology conditions are: FeSO4-7H2O 30~50g/L, ZnCl2 20~40g/L, LaCl35~l 5g/L, NH4C1 60~90g/L, C6H8O7.H2O 10~20g/L, C6H7O7Na3 20~40g/L,2~3g/L ascorbic acid, proper addition, suitable auxiliary addition, PH2~4, lOminutes of electroplate time, DK=2~4A/dm2 of electric current density and 20~30℃ temperature of electroplating solution.The technological study of chloride system electrodepositrion Zn-Fe-La coatings of ternary alloy shows that coordinated usage of main-salt density, C6H7O7Na3 of complexing agent, shining agent, assistance shining agent, and PH are the main factors that affect the compositions and functions of Zn-Fe-La coatings ternary alloy. However, it is disadvantageous for the alloy's electrodepositrion when adding LaCl3 to a certain amount. In addition, conductibility salt NH4C1, ascorbic acid and electric current density, and so on also have influence on coatings. Basically, ascorbic acid won't affect thecompositions of the alloy coatings within the technology, but it will affect more or less the coatings quality.This paper analyzes the influence of the compositions of the coatings and functions of the electroplating solution ( including dispersancy, conductivity and stability, etc. because of adding the Rare earth. The result shows that adding the rare earth can improve the coatings and the functions of the electroplating solution.On the basis of studying the Chlorophosponazo(III) and coloration condition of Re, this paper explores a method of not separating ion Fe but determining the rare earth in coatings through spectrophotographinc. Containing Re content from 0~55ug/mL conforms with Lambert beer's law. Satisfactory and simple operation, this method can be used in routine anadysis.This paper studies the corrosion resistance of Zn-Fe-La coatings ternary alloy by the experiment of soaking the coatings into 5 % NaCl solution, whose PH is 7, and determining the cathode and anode of the coatings and the stable electric potential of 5 % NaCl solution of PH=7. The result shows that there is high corrosion resistance without passivating the coatings, and that the corrosion resistance of Zn-Fe-La coatings of ternary alloy is better than Zn-Fe-La alloy coating, and is much better than Zn coating.From the point of view of the structure of electrical double layer, adsorption, inhibition mechanism and the under electric potential electric deposition mechanism, and based on the various characters of cathode polarization curve while adding kinds of rare earth salt in basic solution , this paper inquires into the mechanism of electrodepositrion of Zn-Fe-La rare earth of ternary alloy.