Cu-Fe Coated Powder

Powder coating is a new multiphase composite powder alloys, which many varieties, unique performance, has been widely used in the defense industry, machinery manufacturing, chemical industry and other fields. Coated powder having micro heterogeneity, coating integrity, according to the different needs of the salient features of each component; having uniformity in the macro, make the product uniform metallurgical structure, greatly reducing or eliminating uneven mixing caused organization of different ingredients, unstable performance shortcomings. In addition, the powder coating can also change the surface properties of the powder, the powder to improve process performance, superior performance prepared materials and powder metallurgy products. Panzhihua Iron converter sludge into the case of an aerosol powder, the powder is more nearly smooth spherical traditional pressed and sintered powder metallurgy applications difficult to use has been certain restrictions. To this end, the subject of the actual converter sludge Panzhihua iron powder, chemical displacement plating method, coated with a layer of copper on its iron surface, both on the original Panzhihua Iron converter sludge surface modification cheap copper coated iron powder metallurgy and composite powder was prepared. In this paper, X-ray diffraction (XRD), scanning electron microscopy (SEM), optical microscopy, chemical titration test means and methods section of the cladding layer microstructure, surface morphology, cladding elements were analyzed; by orthogonal experiment, the effects of additives on coating quality, optimize the process parameters; by comparison test of different passivation agents for copper plating passivation effect; through dynamic tests, effects of temperature, stirring speed, initial copper concentration and pH value on the replacement rate, and on this basis to calculate the diffusion coefficient of copper ions. Studies have shown that, with the increase propenyl thiourea, sodium lauryl sulfate, polyethylene glycol and the amount of sodium acetate is added after the first good poor, i.e., four kinds of additives added volume has an extremum. Optimal dosage is obtained: sodium acetate 15g / L, thiourea propenyl 0.5g / L, sodium dodecyl sulfate 1g / L, polyethylene glycol 5g / L. By metallographic section analysis to know, to get a good replacement plating, Cu deposition rate can not be too fast, adding an appropriate amount of additive package in the original bath, it is possible to obtain a good combination with the matrix, complete continuous copper plating. To protect the copper layer from oxidation during a given period, by the corrosion test results BTA-OP-10-based compound passivating agent excellent effect of copper coated iron powder and draw the optimal dosage is: BTA 0.5%, OP-10 1 ~ 3 g / L. According to the present coating process, additives and deactivators, for 200kg sludge Panzhihua Iron powder-coated copper batch trial, access to satisfactory coating effect, the amount of copper coating and process performance met the requirements for use. Economic and social benefits are substantial. The paper also by analyzing the thermodynamic and kinetic learned in the displacement coating process, when k D / δ, speed k · A · (Me_1 ~ (2+)), the process is controlled by chemical reaction; when k when D / δ, speed (D / δ) · a · (Me_1 ~ (2+)), part of the process is controlled by diffusion. In the surface of the powder required for different nucleation nucleation power ratio