Contamination with foreign material should be avoided. Copper, lead, cadmium, arsenic and antimony can cause problems with loss of brightness, dark deposits or poor colour. They can usually be removed by plating out or by zinc dust treatment.
Iron contamination should not exceed 80-100ppm. Iron can be removed by additions of hydrogen peroxide (1-2ml/l).
| Problem | Reason | Remedy |
|---|---|---|
| Insufficient brightening and levelling Low CD blue colouration | Low Brightener Low current density | Add 0.3-2.0ml/l Brightener Increase current density |
| Poor coverage at low current density | Low chloride Low Carrier | Correct as per analysis Add 2-4ml/l Starter |
| High current density burning | Low temperature Low zinc Excessive current density Organic contamination | Heat solution Add zinc chloride as per analysis Reduce Carbon treat |
| Roughness Pitting | pH too high Suspended solids | Reduce pH Filter |
| Dark deposit | pH too high Iron (II) contamination | Reduce pH Add 1ml/L hydrogen peroxide for every gm/L iron (II) and filter |
| Deposit will not passivate easily | Low Carrier Excessive concentration of decomposition products | Add 2-4ml/l Starter Carbon treat |
| Barrel hole “burning” | Low temperature Low chloride Decomposition products | Heat solution Correct as per analysis Carbon treat |
| Spots developing during passivation | Low starter Poor rinsing after zinc | Add 2-4ml/l Starter Improve rinsing |
| Solution milky or oil on surface | Excess Starter or Brightener | Add Alekos AZ Emulsifier or Solubiliser 5- 20ml/l |
| Problem | Reason | Remedy |
|---|---|---|
| Generally dull deposit | Lack of Brightener Temperature too high Excess Brightener Solution Contamination | Add 0.5-1.0ml/L Brightener Cool solution Work out Brightener, add 1-2ml/L Purifier Add 1-2ml/L Purifier or 10ml/L sodium hypochlorite solution |
| Bright dark deposits | Low Purifier Metallic impurities Low sodium hydroxide | Add 0.25ml/L increments of Purifier Plate out solution at 1-2 A/Sqdm Analyse and correct |
| Poor bright throwing power | Low sodium hydroxide Low Brightener Zinc too high | Analyse and correct Add 0.2ml/L increments of Brightener Plate down zinc content |
| Poor zinc anode solubility | Anode C.D. too high Low sodium hydroxide Excessive use of Purifier | Increase zinc anode area Analyse and correct Reduce additions Do not pour directly over anode |
Contamination with foreign material should be avoided. Copper, lead, cadmium, arsenic and antimony can cause problems with loss of brightness, dark deposits or poor colour. They can usually be removed by plating out or by zinc dust treatment.
Iron contamination should not exceed 80-100ppm. Iron can be removed by additions of hydrogen peroxide (1-2ml/l).
| Problem | Reason | Remedy |
|---|---|---|
| Insufficient brightening and levelling Low CD blue colouration | Low Brightener Low current density | Add 0.3-2.0ml/L Brightener Increase current density |
| Poor coverage at low current density | Low chloride Low Carrier | Correct as per analysis Add 2-4ml/L Carrier |
| High current density burning | Low temperature Low zinc Excessive current density Organic contamination | Heat solution Add zinc chloride as per analysis Reduce Carbon treat |
| Roughness Pitting | pH too high Suspended solids | Reduce pH Filter |
| Dark deposit | pH too high Iron (II) contamination | Reduce pH Add 1ml/L hydrogen peroxide for every gm/L iron (II) and filter |
| Deposit will not passivate easily | Low Carrier Excessive concentration of additive decomposition products | Add 2-4ml/L Carrier Carbon treat |
| Problem | Reason | Remedy |
|---|---|---|
| Burnt deposits at high CD | Cathode CD too high Low metal content Poor agitation | Reduce CD Increase tin content Improve agitation |
| Brittle Deposit | Cathode CD too high | Reduce CD |
| Rough or grainy deposit | Suspended particles in bath Additives out of balance | Check anode bags Filter solution Add additives in increments |
| Treeing | Lack of Carrier | Add Carrier in 1ml/L increments |
| LCD Dullness | Lack of Brightener | Add Brightener in 0.25ml/L increments |
| Dull deposits on corners (areas of high agitation) | Excess of carrier | Add additive in 0.5ml/l increments or Brightener in 0.25ml/l increments |
| Low CD dullness | High temperature | Cool solution |
| Poor throwing power | Metal too high Acid too low Carrier and additive too low | Allow metal to fall by
reducing anode area Adjust acid content Add Carrier in 1.0ml/L increments and additive 0.5ml/l increments (AVOID OVERDOSE) |
| Brown hazy deposit at medium CD | Excess Additive | Add 0.25-0.5ml/L Brightener |
| Peeling of bright deposits | Excess Brightener | Add carrier 1 in 1ml/L increments Reduce Brightener additions Plate out |
| Patchy deposits | Low Brightener | Add 0.5ml/L Brightener |
| Low bath efficiency / slow plating | Low tin metal Low bath temperature | Keep the tin metal between 8 - 22g/l Optimum 15g/l |
It is essential that additions of Alzon part 1 & Part 2 are made based on analysis frequently. If the bath is in constant use, this should be done at least once per shift. Always control the bath between 85-100% concentration.
Metal contaminants build in the bath over time. The density increases and this contributes to poor performance of the Alzon process. Control metallic impurities as per PMD laboratory advice.
All Zincate Processes behave differently with different types of Aluminium. It is key to know the grade of Aluminium you are using to optimise the Alzon process paraments. Further advice on this can be given by our PMD laboratory staff.
Operating temperature is a key variable to control within the Alzon process. Excessive temperatures will result in heavy deposits and poor adhesion. Lower temperatures will result in low thickness deposits.
| Problem | Reason | Remedy |
|---|---|---|
| Streaked/Uneven or Poor Appearance Zincate Deposit | Alzon Parts 1 & 2 out of balance | Analyse and make additions |
| Poor Adhesion | Bath temprature out of range | Adjust bath temperature |
| Combination of Poor Adhesion and Uneven Streaked Deposit | Most likely surface preperation | Analyse each surface preperation step and make additions to optimise process |
| Excessive Gassing in Zincate | Insufficient pre-treatment de-smutting process | Adjust or replace the de-smut |
| Spongy, Thick Deposits / Poor Adhesion | Excessive dwell time in the Alzon Zincate Process | Reduce immersion time |
| Problem | Reason | Remedy |
|---|---|---|
| Dark Streaks | Low Tribrite Replenisher | Add Tribrite Replenisher |
| Low specific gravity | Add Tribrite Conductivity Salts | |
| Metallic contamination | Treat with ion exchange or dummy plate at 20-40 asf | |
| Contaminated nickel pated surface | Improve rinsing after nickel plating or delay plating in the Tribrite bath. | |
| Organic contamination | Carbon treat | |
| Low Tribrite Wetter | Add Tribrite Wetter | |
| Poor coverage | Low specific gravity | Check and adjust with Tribrite Conductivity Salts |
| Low pH | Adjust with ammonium hydroxide | |
| High temperature | Reduce temperature to 29-32°C | |
| Low Tribrite Enhance | Add Tribrite Enhancer | |
| Low current density | Increase current density | |
| High agitation | Reduce agitation | |
| Patchy white deposit | Organic contamination | Carbon treat |
| Dry-on of nickel plating solution | Transfer racks faster, increase rinsing times, lower nickel temperature Delay current initiation in Tribrite bath | |
| Contaminated nickel rinses | Dump and refill rinse tanks | |
| Zinc contamination | Dummy plate at 20-40asf or treat with ion exchange | |
| Low plating rate | Low current density | Increase current |
| Low specific gravity | Add Tribrite Conductivity Salts | |
| Anodes coated | Check anodes and clean | |
| High pH | Lower pH in 0.2unit increments | |
| Low Tribrite Replenisher | Add Tribrite Replenisher | |
| Non-uniform thickness | Low agitation | Increase agitation |
| Low Tribrite Wetter | Add Tribrite Wetter | |
| Low Tribrite Replenisher | Add Tribrite Replenisher | |
| High Tribrite Replenisher | Allow concentration to fall | |
| Poor anode spacing | Check length to anode length and adjust |
