| Copper and its alloys are widely used in electronic,mechanical,decorative and other aspects with excellent electrical conductivity,corrosion resistance and ductility.However,if copper products are exposed to atmospheric and humid environments for a long time,it is likely to occur more serious corrosion.So,its surface must be treated.At present,the popular method is chromate passivation method and the corrosion effect is better and lasting.But the amount of the chromate or Cr O3 is very large in the process,this will pollute the environment seriously.Therefore,to find a new environmentally friendly chromium-free passivation technology is imperative.In this artical,environmental and efficient organic benzotriazole(BTA)were mixed with sodium molybdate,cerium nitrate and benzimidazole to study the synergistic effect between them.Through the accelerated corrosion method,electrochemical impedance test,polarization curves test and electron microscopy scanning technology studied the corrosion resistance of pure copper,which determine the best formula and process conditions.The anti-corrosion treatment process: treating in the inorganic system?treating in the organic system?drying.The inorganic system: 0.1 mol/L HCl+1 g/L Na2 Mo O4+1 g/L Ce(NO3)3solution,at room temperature for 10 min.The organic systems: the ratio is 7:1 of BTA solution and benzimidazole,at 40? water bath conditions for 1.5 h.The corrosion behavior of copper block in 10% H2 S gas confined system after treated with different compound system was discussed.And an impedance and polarization curves in 3.5% NaCl solution changes.The results show that the retention time of copper samples in the Na2 Mo O4 and cerium nitrate is 62 min and 45 min,only 126 min in the BTA solution alone and 55 min in the benzimidazole solution.After the best recipe treatment,the anti-discoloration time reach 475 min,the electrochemical impedance reach 1.78 × 105?.cm-2,and the anti-corrosion efficiency is 98%. |
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