221 Bright Alkaline Cyanide-Free Zinc Plating Process
Name：221 Bright Alkaline Cyanide-Free Zinc Plating Process
221 process is the newest cyanide-free zinc plating technology, It overcomes the problem of embrittlement even in mirror bright and thicker deposits. The metal distribution and the temperature tolerance of the electrolyte are more perfect .
①Mirror Bright Coating
221 Brightness is higher than the Cyanide Zinc Plating Process and Conventional Alkaline Zinc Plating Process, and comparable to Acid Zinc. Passivating without fogging haziness.
②Avoids Yellowing Problem Of Blue Chromate
221 Alkaline Zinc after blue chromate, the coating is deep blue, comparable to Acid Zinc.
③Not Hazy Of Yellow Trivalent Chromating
221 Alkaline Zinc coating is clear and transparent; the Cyanide Zinc Plating coating is tend to fogging be hazy.
④High Bright Deposit Without Embrittlement
⑤High Throwing Power and Even Metal Distribution
High throwing power, and even thickness of coating, greatly saves the consumption of Zinc ingot, saving 25-40% than Acid Zinc, 15-30% than Cyanide Zinc Plating.
Left fig: the thickness of outer coating is 25μm, inner is no less than 17μm 221工艺
⑥ Tolerance to High Temperature
When the bath temperature is 50℃, the coating is still mirror brightness bright.
⑦ Excellent Covering Power
The covering power is superior to Cyanide Zinc Plating and Acid Zinc.
⑧Super Adhesion to Passivation Film
The adhesive force of 221 Alkaline Zinc coating is greater than Acid Zinc, and is comparable to Cyanide Zinc Plating.
⑨Wide Current Operating Range
When the current is 6A in the Hull Cell, the whole specimen panel only has 0.5 cm burnt, when 0.2A, the specimen panel can be bright.
⑩Strong Impurity Tolerance
□The bath can be prepared with ordinary and tap water ,no need for 99% high purity alkaline hydroxide and pure water.
□Strong tolerance of impurity from pretreatment, the test is as follows:
Comments: It is better to carry out the pretreatment completely, and use high purity alkaline and pure water to prepare the cell bath.
⑫Key Points Of Maintenance
221 A brightener 5-25ml/L,
221B Carrier 0.5-1.5ml/L,
221C purifier 0.5-1.5ml/L.
221A brightener 100-200ml/KAH,
221B Carrier 20-70ml/KAH,
221C purifier 10-20ml/KAH.