Plating Process Systems - Metal Finishing Processes

Troubleshooting HCR

Symptom	Usual Causes	Correction
Poor Covering Power
	1. Low current density 2. Poor electrical contact 3. High sulfate (low Ratio) 4. High HCR Catalyst 5. High temperature	1. Increase current density 2. Ensure positive electrical contact 3. Lower sulfate (add barium carbonate) 4. Temporarily, add chromic acid 5. Lower temperature
Low Thickness
	1. Low current density 2. Insufficient time	1. Increase current density 2. Increase time
HCD "burning" (Burn is uniform in shape, i.e., not patchy)
	1. Low temperature 2. Current density too high 3. Chromic acid too low 4. Low sulfate (high Ratio) 5. Low HCR Catalyst	1. Adjust temperature 2. Adjust current density 3. Raise chromic acid 4. Analyze and adjust sulfate 5. Adjust HCR Catalyst to within range.
"Whitewash" (Non-uniform, patchy white deposits)
	1. Substrate not clean 2. Substrate not "active" 3. Bipolarity (exiting from nickel tank and/or entering chromium tank) 4. Low sulfate 5. Low HCR catalyst 6. Ripple from power supply	1. Remove films from substrate surface 2. Activate surface (try weak chromic acid dip prior to chromium 3. Install live current exit/entry (adjust current as necessary) 4. Analyze and adjust sulfate 5. Adjust HCR to within range 6. Inspect rectifier for inoperative diodes and/or use rectifier near rated current output.