Palm Technology - The Electroless Nickel Troubleshooting Guide Page Number 2

1: Measure the bath's temperature with a calibrated thermometer and reduce it to its proper range (generally 185-195 Deg F or 85-90 Deg C)

2: Calibrate, repair or replace the temperature controller if necessary

3: If electrically heated, check that the voltage, current, and resistance are correct

4: If steam heated, check the steam supply, including solenoid, strainer and trap for proper operation

5: Ensure that the temperature sensor is in the solution and not damaged or leaking

1: Observe solution for rapid gassing and the presence of particles around the heater

2: Increase agitation around immersion heaters either with increased air or solution flow

3: Move immersion heaters away from the tank wall to improve solution circulation

4: Change to external pump through heat exchangers

5: If electrically heated, change to derated immersion heaters

1: Observe solution for the presence of nickel hydroxide precipitates

2: Measure the bath's pH with a calibrated pH meter and reduce it to its proper range(generally between 4.8 and 5.2 pH) with 50% sulfuric acid

3: Recalibrate the pH meter or check the accuracy of pH papers used to monitor the bath

4: Check that neutralizer is not too concentrated (normally 50% ammonium hydroxide or potassium carbonate should be use

5: Eliminate any sources of alkaline drag in, such as blind holes and poor rinsing

6: Check steam coils or heaters for leaks and repair or replace if necessary

1: Check bath records to ensure that additions larger than 10 or 15 percent are not being made

2: Make smaller, more frequent additions

3: Make certain that additions are made away from immersion heaters

4: Install an automatic bath controller to make more frequent additions to keep the bath in balance

1: Check that bath loading is below 0.75ft2/gal or 1.9 dm2/L (for some heavy metal stabilized baths)

2: Reduce the number of parts in the bath to obtain a bath loading less than 0.75 ft2/gal or 1.9 dm2/L

3: Ensure that the bath is not plating out on the plating tank or its components

1: Analyze solution for the presence of palladium and tin

2: Eliminate any sources of catalyst drag in, such as blind holes or high barrel loading

3: Improve rinsing

1: Ensure that the proper ratio of hypo to nickel replenishers has been used(generally either 1:1 or 2:1)

2: Where possible, analyze the solution for stabilizers like lead and cadmium

3: If necessary, add additional stabilizers to bring the bath into balance

1: Locate and eliminate any external sources of particles, like blasting or grinding media

2: Keep the tank covered when it is not in use

3: Filter the solution through 1 micron bag filters at a rate equal to 10 tank volumes per hour

4: Totally filter the solution while it is being transferred through a 1/2 or 1 micron filter

1: Transfer the bath through a 1/2 or 1 micron filter bag into a clean second tank every 1 to 3days (period depends on bath formulation)

1: Ensure that potentiostat and wiring are correct connected (tank must be anodic)

2: Set potential to about 0.65 to 0.75 volt

1: Ensure that there is no nickel remaining on the tank or its components after passivation

2: Leave the nitric acid in the tank for a longer period

1: Analyze the nitric acid solution for acidity (it should be at least 20%)

2: If necessary, add more concentrated acid to increase the acidity to 30%

1: Rack the parts so that they do not contact the tank's walls or bottom

1: Filter the solution through 1 micron bag filters at a rate equal to 8-12 tank volumes per hour

1: Increase agitation (air) to ensure that the bath and replenishments are well mixed and that particles are suspended until they are filtered

2: Ensure that the agitation pattern moves particles away from the parts and into the filters (bath should show a uniform, rolling motion)

3: Add solution spargering to increase agitation if using eductors point them away from the parts

1: Improve pretreatment cycle to remove particles

2: Inspect at the last rinse for water breaks

1: Locate and eliminate any external sources of particles, like blasting or grinding media

2: Keep the tank covered when it is not in use

1: Check the quality of the agitation air by blowing it through a white cloth or bag filter

2: Install a filter on the inlet to the air blower

3: Install a filter/separator on the compressed air supply

4: Install a regenerative blower with filter to supply the plating tank

1: Ensure that the proper ratio of hypo to nickel replenishers has been used(generally either 1:1 or 2:1)

2: Where possible, analyze the solution for stabilizers like lead and cadmium

3: If necessary, add additional stabilizers to bring the bath into balance

1: Check bath records to ensure that additions larger than 10 or 15 percent are not being made

2: Make smaller, more frequent additions

3: Make certain that additions are made away from immersion heaters and tank walls

4: Install an automatic bath controller to make more frequent additions to keep the bath in balance

1: If rough and discolored, replace the liner or tank

1: Measure the bath's pH and reduce it to its proper range (generally between 4.8 and 5.2 pH) with 50% sulfuric acid

2: Recalibrate the pH meter or check the accuracy of pH papers used

3: Eliminate any sources of alkaline drag in, such as blind holes and poor rinsing

4: Check steam coils or heaters for leaks and repair or replace if necessary

5: Confirm that the proper ratio of hypophosphite to nickel replenisher is being used (for self pH regulating baths)

1: Observe solution for rapid gassing and the presence of particles around the heater

2: Increase agitation around immersion heaters either with increased air or solution flow

3: Move immersion heaters away from thetank wall to improve solution circulation

4: Change to external pump through heat exchangers

5: If electric, change to derated immersion heaters

1: Pigmented (White, Black, Blue, Eurogray) polypropylene or CPVC tank liners should not be used (replace with natural polypropylene

1: Measure the bath's pH with a calibrated pH meter

2: If the pH is above its normal range, lower it until the solution clears with 50% sulfuric or acetic acid, and then increase it to the proper range (generally between 4.8 and 5.2 pH) with 50% ammonia or potassium carbonate

3: Recalibrate the pH meter or check the accuracy of pH papers used

4: Confirm that the proper ratio of hypophosphite to nickel replenisher is being used (for self pH regulating baths)

1: Check bath records or analyze the bath for orthophosphate to determine the bath's age

2: If older than normal range for bath (often equals 1 or 2 mol/L of ortho), dispose of the bath and make up a new one

3: Add 1% by volume glycolic or lactic acid to clear the solution and then increase the bath's pH to its proper range with 50% ammonia or potassium carbonate

1: Measure nickel concentration of rinse after the plating tank and calculate the amount of bath being lost

2: Reduce drag out by draining or spray rinsing the parts over the plating tank before placing them in the rinse tank

3: Add small amounts of make up concentrate(typically 1-2% per bath cycle) to replace the complexer being lost

1: Analyze the bath's reducer content to determine if it is greatly above its normal range

2: If it is high, reduce it to its proper range through dilution or continued plating

3: Confirm that the proper ratio of hypophosphite to nickel replenisher is being used

1: Analyze the bath's nickel content (very high nickel concentrations may cause some baths to become cloudy)

2: Discard enough of the bath to return its nickel content to normal and add an equivalent amount of make up concentrate(complexer)

3: Check the EDTA solution used for nickel titrations against a standard to ensure its accuracy

4: Confirm that the proper ratio of nickel to hypophosphite replenisher is being used

5: Ensure that the plating tank's volume, used to determine replenishment amounts, is correct

1: Use only deionized water to make up and maintain the bath (tap water contains calcium and magnesium which can precipitat

2: Eliminate any sources of alkaline drag in, such as blind holes and poor rinsing

3: Check steam coils or heaters for leaks and repair or replace if necessary

4: Eliminate any drippage from adjacent equipment

1: Analyze the solution for metals like iron, aluminum and zinc that tie up the bath's complexers

2: Improve rinsing before plating to minimize drag in

3: Dummy the solution electrolessly with steel wool in to filter bag to remove metals

4: Dispose of the bath if is not successful and make up a new one

1: Add replenishers to the bath slowly and in an area with good agitation

1: Test according to ASTM B-733 or AMS 2404 using specimens of the alloy being processed

1: Confirm that the pretreatment procedure is correct for the alloy being processed

2: Confirm that the substrate is the alloy specified (by customer records or analysisor spot tests)

1: After acid activation, examine parts for water breaks, and if present, reprocess through pretreatment cycle

2: Measure the cleaner's temperature with a calibrated thermometer and if necessary adjust it to its proper range

3: Check cleaner records to determine the solution's age

4: If older than normal (generally when more than 200 ft2/gal has been processed),dispose of the cleaner and make up a new one

5: Analyze the solution for alkalinity

6: If alkalinity is lower than normal, add cleaner or dispose of the solution and make up a new one

7: Observe the cleaner for the presence of an oil film on its surface

8: If oil is visible, dispose of the cleaner, carefully clean the tank and make up a new solution

1: After all pretreatment steps, wipe surface with white cloth or cotton swab to detect smut, and if present, improve cycle to remove it

2: Observe the acid for color and for uniform gassing of the steel (iron buildup)

3: If dark yellow and steel does not gas uniformly, dispose of the acid and make up a new solution

4: Check the part after activation for a copper bloom (immersion copper deposit), and if present, dispose of the acid and make up anew solution

5: Analyze the solution for acidity

6: If acidity is lower than normal, add acid or dispose of the solution and make up a new one

7: Observe the acid for the presence of an oil film on its surface

8: If oil is visible, dispose of the acid, carefully clean the tank and make up a new solution

1: Parts should be immersed in the rinse water for long enough to completely remove cleaner or acid films

2: Increase air agitation rate in the rinse water

3: Heat the rinse water (in winter) to improve cleaner and acid film removal

4: Install counterflow rinses to reduce contaminate concentration

1: Observe that the rinses are clear and free flowing

2: If rinses are not, increase the water flow rate

3: Install counterflow rinses to reduce contaminate concentration

4: Observe the rinse water for the presence of an oil film on its surface or tank walls

5: If oil is visible, drain and carefully clean the tank and refill it with clean water

6: Increase the air agitation rate in the rinse water

1: Rinsing alkali and acid coated parts in the same rinse water can result in difficult to remove salt films on the surface

2: Rinse alkali and acid coated parts indifferent tanks

1: Cold rinse water does not remove contaminate films (especially cleaners) well

2: Heat the rinse water to improve cleaner and acid film removal (especially in winter)

1: Check that cleaners will remove (dissolve)the machining or cutting oils

2: If cleaner cannot remove them, change to a different type of oils or a different cleaner

1: Improve rinsing

2: Do not use inhibitors or wetting agents inactivating acids

1: After rinsing, wipe the surface with white cloth or cotton swab to detect rust bloom, and if present, rinse the parts more quickly

2: Poor Adhesion (ferrous alloys)

1: Determine the alloy of the substrate (by customer records or analysis or spot tests)

2: Observe the part while it is in the activation acid to see if it gasses uniformly and within about 10 seconds of being immersed in the activator

3: Try using a nickel strike or higher strength or higher temperature acid

4: If no smut develops and gassing occurs, plate after a quick rinse

1: Determine the alloy of the substrate (by customer records or analysis or spot tests)

2: Use a Woods or sulfamate nickel strike before plating

3: If a strike is not possible, try activating the steel in hot 30% hydrochloric or 20%sulfuric acid

1: After pretreatment, wipe surface with white cloth or cotton swab to detect smut

2: Reduce immersion time in acids and electroclean after activation

3: Add a dispersion agent to the acid at low concentration (requires a subsequent electrocleaning and good rinsing)

1: Analyze the solution for copper which can cause immersion deposits on steel andc ause poor adhesion

2: Dummy the solution electrolessly or electrolytically at low current density and large cathode area to remove copper

3: Carbon treat the solution by circulating it through carbon cartridges or a packed filter

4: Dispose of the bath if or are not successful and make up a new one

5: Identify and eliminate the source of contamination. Look for: Racks or barrels that have been used for copper; contaminated rinses; drag in blind holes or pores; copper alloy substrates not properly activated; incompatible maskants; drippage from work bars or adjacent equipment; steam coil leaks; impurities in agitation air or process water

1: Analyze the solution for nitrates by wet analysis (diphenylamine method) or by specific ion electrode

2: Nitrate contamination is usually due to inadequate rinsing after nitric acid passivation

3: Treat the solution with 1-2 g/L of sulfamic acid which will convert nitrates and nitrites to nitrogen over time

4: Improve rinsing after passivation

5: Test the rinse water after passivation with nitrate test papers to confirm their absence

1: Measure the bath's temperature with a calibrated thermometer and increase it to its proper range (generally 185-195 DegF or 85-90 DegC)

2: Calibrate, repair or replace the temperature controller if necessary

3: If electrically heated, check that the voltage, current, and resistance are correct

4: If steam heated, check the steam supply, including solenoid, strainer and trap for proper operation

5: Ensure that the temperature sensor is in the solution and not damaged or leaking

6: Measure the temperature of the agitation air, and if necessary preheat the air

1: Measure the bath's pH with a calibrated pH meter and increase it to its proper range(generally between 4.8 and 5.2 pH) with 50% ammonia or potassium carbonate

2: Recalibrate the pH meter or check the accuracy of pH papers used to monitor the bath

3: Eliminate any sources of acid drag in, such as blind holes and poor rinsing

4: Check the pH of DI water added to the bath, especially after regeneration

5: Confirm that the proper ratio of hypophosphite to nickel replenisher is being used (for self pH regulating baths)

1: Confirm that the heat treatment cycle is correct for the alloy being processed

2: Heat treat (bake) the part according to ASTM B-733 or AMS 2404

1: Test according to ASTM B-733 or AMS 2404using specimens of the alloy being processed

1: Confirm that the pretreatment procedure is correct for the alloy being processed

2: Confirm that the substrate is the alloy specified (by customer records or analysis or spot tests)

1: After desmutting, examine parts for water breaks (wrought alloys), and if present, reprocess through pretreatment cycle, being careful to avoid over etching the surface

2: The surface of cast parts is usually rough and will show water breaks when the part is properly cleaned

3: Measure the cleaner's temperature with a calibrated thermometer and if necessary adjust it to its proper range

4: Check cleaner records to determine the solution's age

5: If older than normal, dispose of the cleaner and make up a new one

6: Analyze the solution for alkalinity

7: If alkalinity is lower than normal, add cleaner or dispose of the solution and make up a new one

8: Measure the specific gravity of the etch cleaner

9: If higher than normal (often 1.25), dispose of the solution and make up a new one

10: Observe the cleaner for the presence of an oil film on its surface

11: If oil is visible, dispose of the cleaner and make up a new solution

1: After desmutting, surface should be clean and white and free of smut, and if not, reprocess through pretreatment cycle, being careful to avoid over etching the surface

2: Observe the desmutting acid for gassing of the aluminum

3: If it does not gas vigorously and then stop, dispose of the acid and make up a news olution

4: Analyze the solution for acidity

5: If acidity is lower than normal, add acid or dispose of the solution and make up a new one

6: Observe the acid for the presence of an oil film on its surface

7: If oil is visible, dispose of the acid, carefully clean the tank and make up a new solution

1: After zincating, surface should be coated with a thin uniform or mottled grey deposit(depends on zincate type), and if not, reprocess through pretreatment cycle

2: Use the double zincate process

3: Use dilute, alloy zincate solution developed for electroless nickel plating

4: Observe the zincate solution for gassing of the aluminum

5: If the aluminum gasses rapid, the solution is depleted

6: If depleted, add zincate or dispose of the solution and make up a new one

7: Analyze the solution for zinc content

8: If the zinc content is lower than normal, add zincate or dispose of the solution and makeup a new one

1: Parts should be immersed in the rinse water for long enough to completely remove cleaner or acid films

2: Increase air agitation rate in the rinse water

3: Heat the rinse water (in winter) to improve cleaner and acid film removal

4: Install counterflow rinses to reduce contaminate concentration

1: Observe that the rinses are clear and free flowing

2: If rinses are not, increase the water flow rate

3: Observe the rinse water for the presence of an oil film on its surface or tank walls

4: If oil is visible, drain and carefully clean the tank and refill it with clean water

5: Increase the air agitation rate in the rinse water

1: Reduce transfer time between process steps, and especially between the last zincate rinse and plating

2: Reduce rinsing time (generally should not exceed 1 minute)

1: Rinsing alkali and acid coated parts in the same rinse water can result in difficult to remove salt films on the surface

2: Rinse alkali and acid coated parts indifferent tanks

1: Cold rinse water does not remove contaminate films (especially cleaners) well

2: Heat the rinse water to improve cleaner and acid film removal (especially in winter)

1: Check that cleaners will remove (dissolve) the machining or cutting oils

2: If cleaner cannot remove them, change to a different type of oils or a different cleaner

1: Improve rinsing

2: Do not use inhibitors or wetting agents indesmutting acid

1: Accumulation of organic acids and zinc from zincated surfaces will reduce adhesion in many baths

2: If the bath is older than normal, dispose of it and make up a new one

3: Use potassium carbonate instead of ammonia for neutralizing the plating bath

4: Install an ammoniacal strike bath before the electroless nickel bath

1: Carbon treat the solution by circulating it through carbon cartridges or a packed filter

2: Dispose of the bath if treatment is not successful and make up a new one

3: Identify and eliminate the source of contamination. Look for: Racks or barrels that have been used for incompatible processes; contaminated rinses; drag in blind holes or pores; incompatible maskants; drippage from adjacent equipment; steam coil leaks; impurities in agitation air or process water