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Acid Zn Plating troubleshooting.pdf

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D DE EV VE EC CO O A Ac ci i d d Z Zi i n nc c C Ch hl l o or ri i d de e T Tr ro ou ub bl l e es sh ho oo ot t i i n ng g C Ch ha ar rt t Problem Possible Cause Solution High pH Check and lower with 50% Hydrochloric Acid Low ammonia or chloride Analyze and adjust into range Low Brightener Run Hull Cell. Add 0.05% increments to optimize deposit High operating temperature Lower to recommended range High Iron Contamination ( 100 PPM) Hydrogen Peroxide treat.
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    DDEEVVEECCOO A Acciidd ZZiinncc CChhlloor r iiddee TTr r oouubblleesshhoooottiinngg CChhaar r tt  Problem Possible Cause Solution High pH Check and lower with 50% Hydrochloric Acid Low ammonia or chloride Analyze and adjust into range Low Brightener Run Hull Cell. Add 0.05% increments to optimize deposit High operating temperature Lower to recommended range High Iron Contamination (>100 PPM) Hydrogen Peroxide treat.  Add ¼ - ½ pint 35% H 2 O 2 per 1000 gal. Dilute H 2 O 2 at least 3:1 with water. The precipitated Ferric Hydroxide is filtered out Dullness in LCD area (1 to 20 ASF) High Brightener Contact Deveco representative High operating temperature Lower to recommended range High pH Check and lower with 50% Hydrochloric Acid Low wetter Run Hull Cell. Add 1% increments to optimize deposit Dull or poor coverage in MCD to LCD area Low Brightener Run Hull Cell. Add 0.05% increments to optimize deposit High operating temperature Lower to recommended range Low Brightener Run Hull Cell. Add 0.05% increments to optimize deposit Poor surface preparation Improve cleaning, pickling and/or rinsing. No response to brightener, may indicated organic contamination Circulate solution through a carbon filter or batch carbon treat Bath has high temp & low cloud pt. (< 115 F)  Add 1 – 2% Deveco Zinc Clarifier, and/or Cool solution to proper operating temp. High pH Check and lower with 50% Hydrochloric Acid Dull deposit in entire current density range Over-addition of Hydrogen Peroxide Leave air agitation on to help dissipate the H 2 O 2.  Add up to 100 mls Brightener/100 gals solution. Low Zinc metal Analyze and adjust into range Low ammonia, boric acid or chloride Analyze and adjust into range pH too high or too low Check and slowly add 50% HCl to lower it or 45% KOH to raise it. Brightener too high. Wetter extremely high or too low. Run Hull cell and adjust as needed. Work too close to anodes, poor agitation Check and adjust racking and air patterns Low operating temperature Raise temperature above 65 F Burning and/or soft spongy deposits in the High Current Density area Current density is too high Check the rectifier and check the calculation Low Chlorides Analyze and adjust into range Low Wetter Run Hull Cell. Add 1% increments to optimize deposit. Up to 3% total. High Zinc metal Lower to 2.5 oz/gal Zinc Over-addition of Hydrogen Peroxide Leave air agitation on to help dissipate the H 2 O 2.  Add up to 100 mls Brightener/100 gals solution. High pH Check and lower with 50% Hydrochloric Acid Chromium contamination (>200 PPM) Add 1.0 oz Sodium Hydrosulfite/100 gal soln for every 100 PPM of chrome in solution. Poor throwing power No deposit in LCD area High Brightener Reduce brightener additions or cut the bath per Hull cell tests.    DDEEVVEECCOO A Acciidd ZZiinncc CChhlloor r iiddee TTr r oouubblleesshhoooottiinngg CChhaar r tt  Problem Possible Cause Solution HCD areas darker after nitric dip or chromate dip. High Iron contamination (> 100 PPM} High organic contamination. Check tank bottom of tank for parts. Hydrogen Peroxide treat.  Add ¼ - ½ pint 35% H 2 O 2 per 1000 gal. Dilute H 2 O 2 at least 3:1 with water. The precipitated Ferric Hydroxide is filtered out Black staining in LCD areas after chromating High Metallic contamination Copper > 5 PPM Lead > 5 PPM Cadmium > 10 PPM LCD dummy the bath at 2 – 5 ASF for 8 – 12 hours. Or zinc dust treat at 1 lb zinc/1000 gallons of solution to remove 10 PPM trace metals. Filter out the zinc particles so they don’t redissolve into the bath, High Additives Reduce wetter and brightener adds White staining or poor chromate appearance Poor rinsing Dump and rebuild rinses.  Add ½ fl oz./gallon Hydrochloric Acid to the first rinse after zinc plating. Use 2 oz/gal Citric Acid dip in place of nitric acid. Brightener too high or wetter too low Run Hull Cell test  Add 1% increments of wetter to optimize deposit. High pH Check pH and lower with 50% HCl Filter not working properly Check intake, discharge and pressure. High temperature Lower to recommended range. Cloud point below 100 o F  Add 1 – 2% Deveco Zinc Clarifier. High Iron contamination Check tank bottom of tank for parts. Hydrogen Peroxide treat.  Add ¼ - ½ pint 35% H 2 O 2 per 1000 gal. Dilute H 2 O 2 at least 3:1 with water. The precipitated Ferric Hydroxide is filtered out Cloudy turbid solution High Chlorides  Analyze and adjust to range. Brittle zinc plating High Brightener Reduce brightener additions or cut the bath per Hull cell tests. Filter not working properly. Check intake, discharge and pressure. Low anode area Check anode baskets or anode slabs.  Anode particles Check anode bags for tears and/or holes. Filter solution Poor rinsing and/or cleaning Improve rinsing, cleaning and/or pickling Low wetter Run Hull Cell test  Add 1% increments of wetter to optimize deposit. Rough deposit Chrome contamination (>200 PPM)  Add 1.0 oz Sodium Hydrosulfite/100 gal soln for every 100 PPM of chrome in solution. Filter solution. Poor adhesion of zinc Poor cleaning Check for proper preparation and cleaning of work.

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Jul 23, 2017

Chap 005

Jul 23, 2017
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