Stainless Steel Electrodeposited with Zinc is not Good for Storing Thiourea Solution

Abstract

The use of stainless steel 304(SS) tanks to deposit thiourea in industry has been evaluated by studying the corrosion behaviour in 1% thiourea solution, before and after zinc plating. Weight loss method, 1% copper sulphate test, polarization study and AC impedance spectra have been used. The corrosion resistance of SS decreased when zinc was used for electrodeposition. Hence SS vessels electroplated with zinc should not be used to store thiourea solution, in industry.

Effect of reaction parameters in synthesis, characterisation of electrodeposited zinc nanohexagons

“…Among the various metal nanoparticles, zinc nanoparticles (Zn NPs) have been widely investigated because of the unusual properties due to their size and shape, which find wide range of technical applications. Zn NPs have received a considerable amount of attention for their applications in super hydrophobic substrate [4], rechargeable electrical batteries [5], gas sensor [6], corrosion resistance materials [7][8][9], and as substrates in the studies of catalysis [10].…”

Corrosion Behaviour of Stainless Steel 304 Electroplated with Zinc Followed by Blue Passivation

“…DC current was passed for the required time (5 minutes). After electrodeposition the specimen was washed with water and dried [17]. The composition of the post treatment bath solution for blue passivation was 200 g of sodium dichromate and 5 g of KCr(SO 4 ) 2 .12H 2 O (chrome alum).…”

“…When stainless steel was electroplated with zinc, the corrosion potential was shifted to cathodic side -1043 mV. This is due to the deposition of Zn on SS surface [17] so that metal surface becomes more active and hence undergoes corrosion. The LPR value decreases from 503.9×10 1 ohm cm 2 to 5.128×10 1 ohm cm 2 for SS 304 coated with zinc.…”

“…The corrosion current increases from 6.827×10 -6 to 636.0×10 -6 A/cm 2 . Decrease in LPR value and increase in the corrosion current suggest that the effective protective film had not been formed on stainless steel electroplated with zinc [19][20]. These observations suggest that the corrosion protecting efficiency decreases when SS is electroplated with Zn and the corrosion rate increases.…”

“…The corrosion resistance of SS is better than SS coated with zinc, and than SS coated with zinc followed by blue passivation, as revealed by higher LPR value and lower current. Hence, it is suggested that stainless steel coated with zinc should not be used in coastal area, ships and shipyards, and also for storing thiourea in industries [17]. Otherwise machines, made of this combination will undergo corrosion because of the chloride vapours present in coastal area.…”