The invention relates to the technical field of
metal surface passivating treatment, in particular to a
zinc layer trivalent
chromium iridescent
passivation treating fluid used under normal temperature and a usage method thereof. Based on calculation per
liter, the
zinc layer trivalent
chromium iridescent
passivation treating fluid consists of 15-20g of
chromium trichloride, 5-10g of
sodium nitrate, 8-15g of
propane diacid, 15-20g of
citric acid, 5-10g of
sodium dihydrogen
phosphate, 8-15g of
thiourea, 0.8-1.5g of
ferrous sulfate, 0.6-1.0g of
cerium sulfate and the balance of deionized water.Under a continuous stirring condition, the chromium trichloride is dissolved in a part of the deionized water, the
sodium nitrate, the
propane diacid, the
citric acid, the sodium dihydrogen phosphateand the
thiourea are sequentially added and fully dissolved, the
cerium sulfate is added and stirred to completely dissolve, the
ferrous sulfate and the remaining deionized water are added, and the
zinc layer trivalent chromium iridescent
passivation treating fluid is obtained after standing. The zinc layer trivalent chromium iridescent passivation treating fluid has the characteristics of being capable of performing normal
temperature treatment, simple and convenient, easy to control, stable and the like, and a
colored passive film bright, uniform and compact, and good in
corrosion resistancecan be obtained by passivating an encapsulated galvanized sample under the condition that PH (potential of
hydrogen) value is 2.2 in a laboratory.