Summary for phosphoric acid bath life Discussion
Phosphoric acid bath life is the key question here, but the thread does not give a direct service-life answer. Linson Chungath asks how long a phosphoric acid bath used to pretreat aluminum before anodizing will last, and whether its life can be estimated by aluminum weight, area, or acid properties. Ted Mooney says he is not familiar with that pretreatment and asks where it fits in the process, suggesting it may be an acid cleaner or possibly an aluminum bright dipping solution. The exchange therefore highlights that the exact bath type matters before any lifetime estimate can be made. No specific consumption rate, replacement interval, or bath-life formula is provided in the excerpt.
Q. What is lifetime of phosphoric acid bath used for pretreatment aluminium before anodizing? ie; how much aluminium in units of weight, area, or based on properties of phosphoric acid?
Linson Chungath
hobbyist – Trichur, Kerala, India
2004
A. Sorry, I’m not familiar with such a pretreatment. Where in the process does this fit–as an acid cleaner? Are you referring to an aluminum bright dipping solution?
Ted Mooney, P.E.
Striving to live Aloha
finishing.com – Pine Beach, New Jersey
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2004
Q. I thank you for the technical word bright dipping. So I repeat the question–what is the lifetime of phosphoric acid bath used for aluminium bright dipping? ie; how much aluminium in units of weight, area, or, based on properties of acid.(maintainance of the bath).
Thank you
LINSON CHUNGATH
HOBBYIST – TRICHUR, KERALA, INDIA
2004
A. ASM Metals Handbook, Vol. 5, Surface Cleaning Finishing & Coating implies that dragout is the biggest factor in exhaustion of the solution and that the baths are quite tolerant of impurities. It says aluminum phosphate should be held near the tolerable limit of 10 to 12 percent, with a dissolved aluminum content of about 40 g/L.
The Surface Treatment and Finishing of Aluminum and its Alloys again implies that phosphoric nitric baths can, under good conditions, be controlled through dragin/dragout in a “never dump” scenario.
Ted Mooney, P.E.
Striving to live Aloha
finishing.com – Pine Beach, New Jersey
Need quick confidential answers? $25
Need project assistance? $100/hr.
2004