| 摘要 |
PURPOSE:To stabilize a copper foil blackening soln., to prolong the service life of the soln. and to enable continuous use by replenishing the blackening soln. contg. potassium persulfate as an oxidizing agent with potassium persulfate and sodium hydroxide in accordance with the area of copper foil blackened. CONSTITUTION:A copper foil blackening soln. contg. potassium persulfate as an oxidizing agent is replenished with potassium persulfate and sodium hydroxide in accordance with the area of copper foil blackened. The blackening soln. is preferably replenished with 750-1,250g potassium persulfate and 400-600g sodium hydroxide per 50m<2> area of copper foil blackened. The blackening soln. is stabilized, the service life of the soln. is prolonged and continuous use is enabled. |
