Troubleshooting Guide to Chromium phosphate processing

Problem, Cause and Remedy

PROBLEMCAUSEREMEDY
Bath pickles metal and creates dusty coatingAccelerator level too highReduce accelerator level by processing aluminum or autodraining* and adjusting the bath
Low coating weightAluminum concentration too high in bathAutodrain" and adjust
Accelerator too lowAdd accelerator
Concentration too lowAdd make-up chemical
Total acid too high in relation to chromium concentrationAutodrain* bath and adjust
No coatingTotal absence of accelerator in bathAdd accelerator
Sludge plugging nozzlesAluminum concentration in bath too highAutodrain* bath and adjust
Alkaline salts dragged into bathIncrease overflow rate of rinse following cleaner
*Autodraining is a technique whereby the solution is simultaneously being drained and replenished with fresh water and make-up chemical.