| 摘要 |
Corrosion-inhibiting compositions for addition to acidic aqueous compositions for cleaning metals for use in cleaning the surfaces of metal parts which are soiled by water-insoluble deposits which are soluble in acids, containing a partially hydrolysed protein which is a partially hydrolysed gelatin, or a partially hydrolysed casein, or a mixture of these, in which the partially hydrolysed protein has a total nitrogen content of approximately 10 to approximately 20 % by weight and a nitrogen content of the free amino group of approximately 4 to approximately 30 % relative to the total nitrogen content. The invention also relates to aqueous acidic solutions containing the corrosion inhibitor of the invention and processes for treating soiled metal parts with such acidic compositions.
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