Chemically removing workpiece, comprises treating the workpiece to be treated with first aqueous acidic solution of oxidizing compound in first process step, and treating the workpiece resulting from first process step with second solution

摘要

The method comprises treating a workpiece to be treated with a first aqueous acidic solution of an oxidizing compound in a first process step, treating the workpiece resulting from the first process step with a second solution containing surface-active agent and builder compound in a second process step, and treating the workpiece resulting from the second process step with a third solution containing builder compound, diluted solution and hydrogen peroxide and/or hydrogen peroxide-releasing compounds in a third process step, where the zinc casting workpiece is processed with the method. The method comprises treating a workpiece to be treated with a first aqueous acidic solution of an oxidizing compound in a first process step, treating the workpiece resulting from the first process step with a second solution containing surface-active agent and builder compound in a second process step, and treating the workpiece resulting from the second process step with a third solution containing builder compound, diluted solution and hydrogen peroxide and/or hydrogen peroxide-releasing compounds in a third process step, where the zinc casting workpiece is processed with the method. The concentration of the oxidizing compound is 1-30 wt.% related to the treatment bath of the first process step. The treatment bath of the first process step comprises a complexing agent, which contains tartrates and citrates. The first process step is additionally carried out in the presence of surface-active material. The surface-active material is used in a quantity of 0.01-5 g/L related to the treatment bath of the first process step. The concentration of the builder compound in the treatment bath of the second process step is 1-30 wt.% related to the treatment bath. The second treatment bath comprises pickling inhibitors. An energy input is exercised in the second process step by ultrasound of 2-60 W/L. The concentration of the builder compound in the treatment bath of the third process step is 0.5-20 wt.% related to the treatment bath. The concentration of the diluted solution in the treatment bath of the third process step is 0.1-5 wt.% related to the treatment bath. The concentration of the hydrogen peroxide in the treatment bath of the third process step is 0.1-5 wt.% related to the treatment bath. The surface-active material is surfactant. An independent claim is included for a workpiece.