Manufacture Of Iron Foil By Electroforming And Modification Of Rare Earth

This thesis develops the preparation technology of iron foil by electroforming, researchs in detailed the relation of electroforming temperature and cathodic current densities to performance of iron foil. And the effect that rare-earth compound in the solution take on electrodeposited iron are also discussed simply in this thesis.Making sure the iron foil, 30~50um in thickness, to be stripped from the cathodic intant and ensuring the stability of electroforming solution are the two key problems in preparing iron foil by electroforming technology. Solving the former problem not only optimizes the technological parameter, but also puts pure titanium forward as suitable cathodic material. And the stability of the solution under high temperature can be raised to more than 80% by adding 20g/L stabilizer SS.Magnetic performance of iron foil is studied by testing its magnetic hysteresis curve. And the results show that the coercive force of electroforming iron foil is in direct proportion to cathodic current densities, and is inversely proportional to electroforming temperature; and the maximal permeability of iron foil is inversely proportional to the cathodic current densities and is in direct proportion to electroforming temperature.The electric performance of iron foil is analyzed by measuring its resistively ratio. The results indicate that the resistively ratio of electroforming iron foil is larger than that of industrial pure iron because of intercrystalline scatter; while being electroformed in the temperature between 85 degree~95 degree, the gained iron foil will have a low resistively ratio. On the contrary, the resistively ratio of iron foil increase while the cathodic current densities increases.The mechanical performance of iron foil is analyzed by testing its hardness. The results show that micro-hardness of iron foil gained by electroformed in high cathodic current densities iscomparatively high, and that got by electroformed in high solution temperature is low.Having been treated with vacuum annealing, the coercive force of iron foil be reduced, but the maximal permeability is increased. Meanwhile, because of the declination of resistivity ratio and hardness, the tenacity of the iron foil be improved.To make sure the cathodic current densities is 6~8A/dm2, pH figure is 1-2, electroforming temperature is 90-96 degree in the system containing 110~140g/L Fe2+, 60g/l NaCl, 30-50 micron in thickness gained under this condition. Following is magnetic parameters of iron foil: coercive force 58.9A/m, maximal permeability 5.6Ω·10-3H/m, saturation magnetic induction intensity 1.1707T, residual magnetism intensity 0.7677T, resistively ratio (10.8-11.7)Ω·10-8Ω·. m (before annealing ) and (9.9-10.6) ×10-8Ω·m (after annealing at temperature of 650); Hardness:80~90kg/mm2 (before annealing) 50~60kg/mm2 (after annealing at temperature of 650). Tensile strength 310MN/m2, percentage elongation reaches to 8%. Cathodic current efficiency reaches to more than 95% and the electrodeposited speed of iron foil reaches to 95 Mm /h.Besides 0.06 percent of the corbon, the analytical result of purity show that other impurity elements are rarely contained in iron foil. The purity of iron foil could reach to more than 99.9%.Adding rare-earth compound in the system of electroforming, influences antioxidation of Fe2+ at low temperature. The antioxidative ability doesn't exist with the increase of the temperature. After adding trace rare-earth compound, cathodic polarization increases. It thus make the grain of iron foil thinner, and increase cathodic current efficiency by 3%. However, rare-earth doesn't coelectrodeposit with iron.According to the electrode materials and stabilization technology, a trial production line which could produce iron foil of 30 um in thickness and 20 cm in wideness was designed and essembled, and will also provide a basic reference for the industrialized popularization of the technology.