ZINC PLATING SYSTEMS ZCL NH4

Transcription

1 Zinc Plating Systems ZCL NH 4 is a two component, water soluble, low ammonia zinc plating system suitable for either rack or barrel plating operations. is characterized by ease of control, consistent day to day operation, high temperature tolerance and excellent chromate receptivity. v Mirror bright finish v Excellent chromate receptivity v Temperature tolerance up to 110 F (45 C) v Suitable for either rack or barrel operations v Ease of plating bath control v Excellent adhesion and ductility Pavco Inc John Crosland Jr. Dr. Charlotte, NC Phone Fax Toll Free

2 Pavco ZCL NH 4 Page 2 Operating Parameters Barrel Operation Zinc: Potassium chloride: Range oz/gal g/l oz/gal g/l Ammonium chloride: 4-8 oz/gal g/l Current Density: 1-15 amps/ft 2 Rack Operation Zinc: Potassium chloride: amps/dm oz/gal g/l oz/gal g/l Ammonium chloride: 4-8 oz/gal g/l Current Density: 1-80 amps/ft amps/dm 2 Optimum 3 oz/gal 22.5 g/l 20.0oz/gal 150 g/l 6 oz/gal 45 g/l 3.5 oz/gal 26 g/l 20.0 oz/gal 150 g/l 6 oz/gal 45 g/l Starter 2-6% 4 % ZCl BRT II % 0.1% ph: Temperature: F C Anode to Cathode Area: 1:1 minimum 90 F 32 C

3 Pavco ZCL NH 4 Page 3 Equipment Tank: A polypropylene, PVC, or Koroseal lined tank is required. Anodes: Use Special High Grade (SHG 99.99% pure) zinc balls or slabs Anode Baskets: Titanium baskets are required. Keep the baskets filled with zinc anodes all the time and not to exceed 9 volts on the rectifier. Anode Bags: Nylon or polypropylene bags are required for rack operations. Anode S-Hooks: Nickel plated S-hooks. Anode Bars: Use copper anode bars, preferably shielded with plastic. Filtration: Use a 5-15 micron cartridge packed with a filter aid or activated carbon. Filtration speed should be at least 1 tank turnover per hour. Sand filters have been found to work quite satisfactorily. Rectifier: Up to 12 volts Temperature Control: The system is tolerant to temperatures ranging from F (18 43 C). A titanium heat exchanger is recommended for both cooling and heating. Ventilation: Recommended Agitation: Air agitation is mandatory for rack operations. Optional Equipment Automatic ph controller Automatic brightener feeder Automatic temperature control

4 Pavco ZCL NH 4 Page 4 Maintenance of the Solution Zinc Potassium Chloride By analysis Bath Makeup per 1000 gallons (3785 l) 1. Prepare a lined tank by leaching it with 5% hydrochloric acid for hours. 2. Rinse the tank 3. Fill the lined tank with 500 gallons (2000 liters) of water. 4. Add 45 gallons (170 liters) of 62.5% liquid zinc chloride and mix well to dissolve. 5. Add 375 pounds (170 kg) of ammonium chloride and mix well to dissolve. 6. Add 1125 pounds (510 kg) of potassium chloride and mix well to dissolve. 7. Hang slab anodes or zinc filled titanium anode baskets in the bath. 8. Add 40 gallons of Starter 9. Add 0.5 gallons of ZCl BRT II. 10. Add warm water to the 1000 gallon (3785 l) level. Analytical Procedures By drag-out & analysis Ammonium Chloride By drag-out & analysis Starter ZCl BRT II By drag-out & analysis 1 gal / 20,000 30,000 amp hrs (1 l / 5,000 8,000 amp hrs) Zinc Reagents 1. Acetate Buffer -To makeup, dissolve: a)180 grams of sodium acetate b) 30 ml of acetic acid c) Add de-ionized water to make one liter 2. Xylenol Orange Indicator-To make this indicator liquid: a) One gram of Xylenol Orange b) Dissolved in 1 liter of de-ionized water M EDTA Solution Procedure 1. Into a 400 ml beaker pipette a 5 ml bath sample. CAUTION: Fumes are poisonous if using this method with a cyanide bath. 2. Add 150 mls de-ionized water. 3. Add 50 ml acetate buffer. 4. Add indicator 5. Titrate with 0.1 M EDTA until the color changes from red to yellow Calculation: ml of titration.176 = zinc in oz/gal ml of titration 1.32 = zinc in g/l

5 Pavco ZCL NH 4 Page 5 Analytical Procedures Cont d Total Chloride - Free Chloride Reagents 1. Buffer (Mix dextrin and calcium carbonate in a 1:1 ratio) 2. Chloride Indicator Dissolve: a) 0.2 g of Dichlorofluorescein b) 70 mls of methyl alcohol c) De-ionized water to make 100 mls N silver nitrate solution Procedure 1. Pipette a 1 ml sample of zinc chloride plating bath into a 250 ml Erlenmeyer Flask 2. Add 100 mls of de-ionized water. 3. Add one scoop, approximately 2g, of buffer. 4. Add 1 ml of indicator 5. Titrate with 0.153N silver nitrate until the color changes from yellow to pink Calculation 1. mls of Silver Nitrate x = oz/gal total chloride (A) A x 7.49 = g/l total chloride (Am) 2. Zinc in oz/gal x = oz/gal chloride associated with the zinc metal (B) B x 7.49 = g/l chloride associated with the zinc metal (Bm) 3. A - B = oz/gal free chloride (C) Am - Bm = g/l free chloride (Cm) Iron Test and Treatment per 1,000 gallons (3785 l) Procedure 1. Into a 100 ml beaker add 30 ml of clear bath sample (if the sample is not clear, filter it). 2. Add 1 ml of 3.5% hydrogen peroxide 3. Determine the concentration of the iron in the bath by the intensity of the color change. No change Slight precipitate Heavy precipitate - no iron - moderate iron - high iron 4. If the test indicates moderate or high iron, or if barrel spots are present, treat the bath for iron as follows:. Dilute one pint (500 ml) of 35% or 50% hydrogen peroxide to 1 gallon (3.785 L) with water. Mix this diluted peroxide throughout the plating bath. Repeat steps 1 to 4 until the majority of the iron is precipitated. Filter out the precipitated iron.

6 Pavco ZCL NH 4 Page 6 Normal Panel Control Panel Normal Low Current Density Problem High ph Low total chloride Low ZCl BRT II High Current Density Problem Black Burn Gray Low Zinc, Low Ammonium chloride, High ph, Low Starter, Low temperature Chromium Contamination Blister Chromium contamination Skip Hull Cell Panel Observe From Left to Right Area 1 High Current Density Area 2 Mid Current Density Area 3 Low Current Density Metal Contamination Problem Blackish Discoloration Metallic Contamination (either copper or cadmium) of the plating bath or the bright dip ener Problem Low ZCl BRT II Semi High and Low Current Density Problem Frost Gray Low Starter Low ZCl BRT II

7 Pavco ZCL NH 4 Page 7 Iron Problem Black Discoloration High Iron (Black color shows up after the bright dip or chromate) Pavco, Inc. s Hull Cell Scale 1 AMPS. 2 AMPS. 3 AMPS. 5 AMPS. TOTAL CURRENT 3 AMPS. 5 AMPS. PANEL EDGE GM./1000 ML. 7.8 ML./1000 ML. AMPS./SQ. FT. 267 ML. OR 534 ML. HULL CELL OR 267 ml Hull Cell Agitation Mechanical or Air Temperature 90 F, 32 C Current & Time 2 amps/5 minutes 2 GM/267 ML. HULL CELL = 1 OZ./GAL. = 6.25 LBS./100 GAL. 2 ML./267 ML. HULL CELL = 0.96 FL. OZ./GAL. = 6 PTS./100 GAL. 4 GM. 534 ML. HULL CELL = 1 OZ./GAL. = 6.25 LBS./100 GAL. 4 ML./534 ML. HULL CELL = 0.96 FL. OZ./GAL. = 6 PTS./100 GAL. CU. FT. X 7.48 = GAL. GM/L X = OZ./GAL. OZ./GAL. X 7.5 = GM/LITER GAL. X 3785 = ML. A/SQ. FT. X = A/SQ. DM. PANEL AMPS./SQ. FT ML. HULL CELL

8 Pavco ZCL NH 4 Page 8 Trouble Shooting Chart Problem Cause Solution High current density burn Low zinc level Add zinc chloride High current density area bright-dips black, or barrel work exhibits Low current density are dull or hazy Poor low current density coverage High current Low ammonium chloride Low temperature Low Starter High iron High ph Low total chloride Low Starter Metallic or organic contamination High ph Low chloride Low Starter Low/High BRT II Metallic contamination High zinc level (>6oz/gal or 45 g/l) Excess peroxide added Organic contamination Reduce current Add ammonium chloride Raise temperature Add Starter Treat for iron with diluted hydrogen peroxide Reduce ph Add potassium or ammonium chloride Add Starter Treat with zinc dust or carbon Reduce ph Add Potassium or Ammonium Chloride Add Starter Check BRT II level in hull cell Treat with zinc dust Dilute the bath Electrolyze bath Treat with carbon

9 Pavco ZCL NH 4 Page 9 Trouble Shooting Chart Cont d Problem Cause Solution Low current density area bright dips black Metallic contamination Treat with zinc dust Overall Haze Low Starter Add Starter Low BRT II Inadequate agitation Poor cleaning Work rusting before plating Poor bright dip Blue bright chromate out of balance or contaminated Temperature too high Add BRT II Increase agitation Improve cleaning Acidify rinses Remake bright dip; try HCl instead of nitric acid Remake chromate Decrease temperature Overall Dullness Low Starter Add Starter Low BRT II Metallic contamination High temperature temperature too high ph too low Organic contamination Add BRT II Treat with zinc dust Decrease temperature decrease temperature Raise ph Treat with carbon Slow Plating Speed Low zinc level Add zinc chloride Low chloride level Low Starter Add potassium or ammonium chloride Add Starter Weak pickle or pickling problem Add more hydrochloric acid to the pickle or make a new pickle Low temperature Low current Raise temperature Increase current Smut formation in pickling Add PavPrep to the pickle

10 Pavco ZCL NH 4 Page 10 Trouble Shooting Chart Cont d Problem Cause Solution Roughness Inadequate filtration Improve filtration Low Starter Add Starter Low anode area Increase anode area Particles from anodes Bag the anodes Current too high Lower the current Blistering Poor cleaning &/or pickling Improve pre-treatment Organic contamination Treat with carbon Metallic contamination Treat with zinc dust Chromium contamination Treat with peroxide High current Lower current High BRT II Hold BRT II Low Starter Add Starter Flaking or star dusting High BRT II Hold BRT II Low Starter Add Starter Current interruption Check all contacts High current Lower current High ph Reduce ph

11 Pavco ZCL NH 4 Page 11 Waste Treatment Dispose of the concentrates or solutions thereof according to local waste treatment regulations. Safety Handling Pavco mandates that the following safety equipment be used when handling chemicals in an electroplating environment: safety glasses, face shield, plastic or rubber apron, rubber gloves and safety shoes. Chemicals should only be handled by trained and experienced personnel. Storage Store Pavco products in a clean, well ventilated room which temperature remains above 45 F (7 C). Pavco products should remain in their original container with the lid or cap tightened. Drum pumps or pails must be clean prior to dispensing Pavco products to prevent contamination. If Starter or BRT II freeze during shipment or storage, warm the product and mix it well before use. Emergency Procedures Refer to the MSDS for detailed emergency procedures Eye Contact Seek immediate medical attention. Flush the eyes with water for 15 m minutes. Skin Contact Remove all contaminated clothing. Wash the skin with soap and water. Seek medical attention Inhalation Remove the person to an area with fresh air. Seek medical attention if necessary Ingestion Seek immediate medical attention Spill Dike the area to contain the spill. Refer to the MSDS for clean-up. Notify the proper authorities if required. Product Description & Shipping Starter (ZB 650) is a clear amber liquid. The specific gravity is between 1.0 and 1.1 with a ph less than 7 ZCl BRT II (ZB 1010) is a clear liquid. The specific gravity is between 1.0 and 1.1 with a ph less than 6. Both products are available in in 5 gallon containers, 55 gallon drums, or 275 gallon totes Revision Date: 2/8/11 ZINC PLATINGSYSTEMS ZCL NH4 WARRANTY AND DISCLAIMER Technical information and recommendations contained herein are believed to be reliable, however, the accuracy or completeness thereof is not guaranteed. No statement or recommendation shall constitute a representation unless set forth in an agreement in writing by the seller and manufacturer. NO WARRANTY OR MERCHANTABILITY OR WARRANTY OF FITNESS FOR A PARTICULAR PURPOSE IS MADE. The following warranty is made in lieu of any other warranties, express, implied, or statutory. Products are warranted to be free from defects on material and workmanship at the time sold. The sole obligation of the seller and manufacturer under this warranty shall be to replace any product defective at the time sold. Under no circumstances shall the manufacturer or seller be liable for any loss, damage, expense, direct or consequential, arising out of the use of or inability to use the product. Materials shall not be returned to the seller or manufacturer without express written permission. No information or suggestions given by us shall be deemed to be a recommendation to use any product in conflict with any existing patent rights.