Environmental galvanizing process -A02-450 series alkaline non-cyanide zinc brightener Instructions

A02-450 series alkaline non-cyanide zinc brightener? - Manual 1, features with excellent throwing power and coverage for complex shapes or large planar workpieces, more balanced level of area coating thickness. Barrel plating, hanging plating apply. ? High and wide tolerance range of the zinc ion concentration and M ratio, easy operation and maintenance. ? Bright coating on the zinc fast. Adhesion and ductility are very good. ? Can be used in conjunction with the company Trivalent chromium passivation agent, passivation layers satisfactory? Light stabilizers less decomposition products, the product has excellent performance in high-temperature baking and high temperature and humidity test. ? In conjunction with the company A03-120 final electrolytic agent can help remove surface after pickling "black film" rhyolite holes and other defects, improve plating quality. ? Does not contain a chelating agent, wastewater treatment easier compliance. 2, bath composition and operating conditions 2.1 bath composition namescope Zn2 + concentration 8 ~ 15g / L NaOH content of 100 ~ 140g / L A02-450A (main light dose) 10 ~ 16ml / L A02-450B (sub light agent) 1 ~ 2ml / L A02-450D (softener) 10 ~ 20ml / L temperature 20 ~ 30 ℃ rack plating cathodic current density: 1.5 ~ 4.0A / dm2 Barrel: 0.5 ~ 1.2A / dm2 bath filtration Continuous filtration and overflow iron anode material (zinc dissolution tank set up) 2.2 Preparation of the bath: 2.2.1 All equipment must be thoroughly cleaned. 2.2.2 a 50% solution of zinc bath water, stirring carefully added part of the calculated sodium hydroxide to maintain the 250g / L or so, hanging into the installed ingots of iron baskets were dissolved zinc . When zinc reached 18g / L, with a filter pump into the plating tank (to be in a safe temperature of the filter device, normally every less 40 ℃). , Step 2.2.1 2.2.3 repeated until the desired dissolved zinc content, while the calculated sodium hydroxide are added all, diluted with water to 80% level of the plating tank work, and cooled to a temperature cycle (20-28 ℃). 2.2.4 impurity electrolysis process. Electrolysis current density 0.15-0.30A / dm2, the electrolysis time to be set depending on the raw material impurities, impurities, long electrolysis time, typically 12 to 24 hours. Note that not power the electrolysis process, or have been deposited at the cathode reintegration of heavy metal impurities in the bath when the power lead to naught. After the electrolysis is complete, the Hull cell tableting 0.5A × 10min, 2A × 10min after full bright light can be added to the plating bath agent. 2.2.5 adjust the level to work level, uniform filtration cycle, confirm the temperature (20-28 ℃) after the trial plating. 3, bath maintenance Zinc: According to the analysis, by dissolving soluble zinc zinc tank control. Sodium hydroxide: According to complement the analysis. A02-450A: Hall-cell test, the amount of additional recommendations 200-300ml / KA.h. A02-450B: Hall-cell test, the amount of additional recommendations 100-150ml / KA.h. A02-450D: together with sodium hydroxide fill in, the amount of additional A02-450D: sodium hydroxide = 1: 4-7. Should sodium hydroxide or plating tank with poor water quality, the need to increase the amount of A02-450D. 4. Analysis 4.1.1 4.1 Determination of zinc reagent 1) pH = 10 buffer solution 2) chrome black T indicator 3) 0.05M EDTA standard solution analysis 4.1.2 Step 1) In 250 ml Erlenmeyer flask Add 100 ml deionized water 2) with a pipette to take 2 ml Erlenmeyer flask bath 3) adding 10ml pH = 10 buffer solution, adding a few drops of chrome black T indicator 4) standard 0.05M EDTA titration, titration to color of the solution changed from purple to blue as the end point. 4.1.3 Calculation Zn2 ??+ (g / L) = M - molar concentration of the standard solution of EDTA mol / LV - milliliters consumed during titration EDTA standard solution, mL 4.2 NaOH Content Determination 4.2.2 Reagent 1) 10% Bacl2 solution 2) phenolphthalein indicator 3) standard 1.0M hydrochloric acid solution 4.2.3 Analysis Step 1) bath with a pipette 5 ml in 250 ml volumetric flask, add water 100 ml 2) 10% barium chloride 20ml, shake . 3) add 2 drops of phenolphthalein indicator. 4) to 1.0M hydrochloric acid standard solution titration to red disappears, 30 seconds for the end no longer red. 4.2.4 Calculation m- standard molar concentration of hydrochloric acid solution .mol ??/ L. V- consumption with standard hydrochloric acid solution milliliters .ml 5, Troubleshooting Fault Cause Remedy A. Inadequate blistering ① plating process to strengthen Pretreatment ②A02-450B light overdose activated carbon treatment or stop plus A02-450B B. current inefficient, slow deposition ① low adjust the zinc ion concentration of zinc ion concentration was maintained at 8 ~ 15g / L ② bath temperature is too low to keep the bath temperature 20 ~ 30 ℃ ③ brightener A severe overdose see paragraph 2:00 of cyanide pollution ④ ⑤ added hypochlorite conductive anode bad checks or points of contact. ⑥ reduce excessive loading of the workpiece C. pendant dark rough coating dispersion is poor. ① zinc ion content is too high, with low levels of sodium hydroxide adjusted analysis. Controlling the zinc ion concentration in the 10 ~ 15g / L, the concentration of sodium hydroxide and the ratio of the zinc ion is preferably 10 to 12. ② lack of an appropriate amount of additional A02-450A brightener brightener. ③ current density is too large to reduce the current density. ④ bath temperature is too high to maintain the bath temperature 20 ~ 30 ℃. D. low current density area ① poor glittering high content of zinc ions, along with low sodium content analysis adjustment, control of zinc ion concentration in the 10 ~ 15g / L, sodium hydroxide and zinc ion concentration ratio of 10 to 12 is appropriate . ② A02-450B additional A02-450B insufficient light dose according to Hull cell test piece amount. ③ current is too low increase the current. ④ bath temperature is too high to maintain the bath temperature 20 ~ 30 ℃. ⑤ metal impurity contamination weak solution or additional A02-450D E. brightener consumption high zinc content is too high ① adjust zinc ion concentration. Adjusting the temperature of the bath temperature is too high ② 20 ~ 30 ℃. ③ anode area is too small increase anode area ④ bath contamination weak solution and activated carbon treatment. F. lower zone passivation dark, even exposed at the end (iron) metal impurity ions more zinc treatment or weak solution.