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Ted Mooney, P.E. RET
Pine Beach, NJ
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for Metal Finishing since 1989
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What is 'P ratio' in zinc phosphating bath and how to determine it?
Q. Can someone tell me a method of determining the "P ratio" of a zinc phosphate conversion coating?
RFQ: If you know of a testing laboratory that can provide this analysis I would very much like to know of that.
Ohio
1998
Ed. note: Sorry, this RFQ is old & outdated, so contact info is no longer available. However, if you feel that something technical should be said in reply, please post it; no public commercial suggestions please ( huh? why?)
A. ACT test lab in Detroit [is a testing lab that can provide that analysis]
Jeff B [surname deleted due to age of posting]- Windsor , Ontario , Canada
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Q. Can anyone throw light on P ratio in zinc phosphating bath.
Manish [surname deleted due to age of posting]UL - India
2005
A. The P ratio is a measure of the forms of phosphate obtained from zinc phosphating.
Miyawaki, Okita, Umehara and Okabe(1) proposed that P ratio = Phosphophyllite (Zn2Fe(PO4)2.4H2O)/[Phosphophyllite + Hopeite (Zn3(PO4)2.4H2O)].
They found that the P ratio was higher in dip applications with a low Zn:PO4 ratio.
The P ratio may be affected by a number of factors, including temperature, agitation and method of application.
(1) Miyawaki, T., Okita, H., Umehara, S., and Okabe, M., Proc. Interfinish 80, Kyoto, 1980
Brian TerryAerospace - Yeovil, Somerset, UK
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Q1. What exactly is the definition of 'p'ratio in zinc phosphating process? Generator manufacturer - Rudrapur, Uttranchal, India Ed. note: To limit confusion let's continue to restrict this discussion to Q1; Q2, the TA/FA ratio, is addressed in topic 47351 and several other threads. A. Dear Neeraj, The free acidity and total acidity of zinc phosphating bath depends on the formulation and operating conditions [see topic 47351].  T.S.N. Sankara Narayanan - Chennai, Tamilnadu, India (ed.note: The good doctor offers a fascinating blog, "Advancement in Science" ) 2005 |
Q. Can you give me the details for how to calculate p-Ratio of phosphate bath?
We have completed SEM (Scanning Electron Microscope)for phosphate panel.
Sr. Engineer,AME - Satara, India
December 9, 2011
Ed. note: We appended your inquiry to a thread where the question has already been answered by Brian Terry and TSN Sankara. Please advise of remaining questions or anything which is unclear.
Q. I want to understand ... what are the Factors effecting P-Ratio?
Can anyone help me by giving reference of some good online study material?
Have to make an Official report (Fish-Bone diagram).
I am virtually Illiterate in this Subject.
- Jamshedpur, Jharkhand, INDIA
May 14, 2012
Ed. note: Brian Terry has mentioned one paper on the subject. It looks like scholar.google.com returns a pretty good list of papers on the subject if you try the search term "phosphophyllite hopeite coating". Good luck.
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