As a member of the eBay Partner Network & Amazon Affiliate we receive compensation for qualifying purchases

Home /
Search 🔍
the Site
pub Where the world gathers for
plating, anodizing, & finishing Q&As since 1989


What is Tri-cationic phosphating?

Hi, please tell me formula of tri-cationic phosphating.

Sunil Juneja
buyer - Faridabad, Haryana, India
March 28, 2009

"Preparation of Metals for painting"
by Samuel Spring

on AbeBooks

or Amazon

(affil links)

"Phosphating of Metals"
by Werner Rausch

on AbeBooks

or eBay or


(affil links)

A. Hi, Sunil. A tri-cationic phosphate is one that contains ions of zinc, manganese, and nickel. There are many patents on the subject, and consequently many different formulations. The usual idea is that you buy one from your pretreatment supplier and follow the instructions on their technical data sheet. It may be possible to formulate a tri-cationic phosphate yourself, but I am not personally aware of any generic formulas. You could search expired patents. Good luck!


Ted Mooney,
Ted Mooney, P.E.
Striving to live Aloha - Pine Beach, New Jersey
April 3, 2009

A. Ah! At last somebody wants to know this! Good.

Ted is right, Actually we are manufacturers of metal pretreatment chemicals. It is a combination of 3 cations namely, ZINC, MANGANESE and NICKEL, all in a fixed combined proportion.

Technically speaking this is the best form of phosphating available. The mother liquor of such phosphating solution will be PALE GREEN, and the colour of the solution in the tank will be sea green.

This can be operated in COLD system giving excellent results, so I don't understand why people operate in hot.

Such phosphating gives excellent corrosion resistance in a salt spray chamber with low micron build up; the coating is smooth and is user friendly. Take care to maintain TOTAL ACID, and FREE ACID in the tank, and use accelerator properly.

Shankar Omprakash Khandelwal
- Coimbatore, Tamilnadu, INDIA
April 4, 2009

A. Hi Mr.Sunil Juneja,

As Mr.Ted Mooney said, Tri cationic phosphate contains Zinc , Nickel & Manganese. Zinc improves adhesion , Nickel contributes to corrosion protection & Manganese improves wear resistance.There is no generic formula or chemistry available to manufacture this chemicals since there are many patents and formulations. I am sure no one will give you the formulations. Hence it is advised to discuss with pretreatment chemical supplier for the products.

Mr.Shankar Omprakash Khandelwal has referred to cold phosphating. But please understand the process time, Phosphate coating weight, Crystal structure(SEM pictures),P - ratio are not same between cold & hot phosphates. It is the main reason mostly hot phosphate process is preferred over cold phosphating.


paint shop manager
Chennai, Tamilnadu, India

April 14, 2009

A. Hi Sunil
Tri cation Phosphate means combination of Zn, Ni, Mg cation in phosphoric acid and chlorate; nitrate was also used in accelerator of to increase rate of reaction. TCP is preferred in hot process because of formation of required coating weight and granule size.


April 21, 2009

A. Sir,
Tricationic phosphating is based on Zn, Ni, & Mn.
The concentration of Total acid with Free acid needs to be maintained very strictly. To get better result, auto-dosing of Accelerator (on the basis of consumption/lot) needs to be procured.

Rahul Deshpande
- Aurangabad -Maharashtra India
July 13, 2010

Q. Dear sir,
We would like to know how to produce 3 in 1 metal pretreatment chemical for powder coating. Exact formulation.

Mitesh Bhayani
- Mumbai, Maharashtra, India
February 10, 2012

A. Hi, Mitesh. It isn't clear to me whether you are speaking of tri-cationic Zn-Ni-Mn as three-in-one, or whether you mean an iron phosphate process that does cleaning/activating/phosphating in one tank and is sometimes called three-in-one.

But in either case, nobody is going to blow their trade secrets and tell you the exact formulation of their proprietary process. You might as well ask for the exact formulation of Coca-Cola, or the shop drawings for a Lexus.

But, as mentioned, what formulators usually do is obtain copies of all the patents in that area (which is much easier these days than in the past, since they are all on line) and formulate to the expired ones. Naturally, you must also have on hand the books that explain phosphatizing in detail. Good luck.


Ted Mooney,
Ted Mooney, P.E.
Striving to live Aloha - Pine Beach, New Jersey
February 10, 2012

Q. Comparison between Di-cation Phosphating Process vs. Tri-cation Phosphating Process

Sharad Dhanait
- Nashik, India
March 22, 2013

A. Hi Sharad. Assuming that by "di-cationic" you mean zinc+nickel, rather than "calcium modified" , the advantage of the addition of manganese is probably adhesion and durability for better wear and tear performance.

Please try to explain your situation, and you will probably get well-directed help tailored to your situation in this forum. This forum is quite good at that; whereas abstract questions are answered better and with deeper insight by books. Good luck.


Ted Mooney,
Ted Mooney, P.E.
Striving to live Aloha - Pine Beach, New Jersey
March 25, 2013

A. The Di-cationic is having two cations (e.g.Zinc and Calcium) while Tr-cationic is having three cations (Zinc, Nickel and Mn) in Phosphoric acid

Rahul Deshpande
- Aurangabad, Maharashtra
August 18, 2013

Q. Does the square feet area of components to be dipped in pre-treatment and tri-cationic phosphate bath affect the quality of pre-treatment and phosphate respectively?

Rahul Deshpande
- Aurangabad, Maharashtra
December 12, 2013

Q. Respected sir,
I am using di-cationic zinc phosphating chemical; as well, my chemical supplier is also saying our phosphating product is di-cationic. But how will we prove it. If you have any method for cation testing please explain.

December 12, 2013

Q. Hi. I want comparison between tri and di Cationic, and disadvantages of each of them.
Do you have any paper?
Thank you.

Amir rezayi
- thehran,iran
December 29, 2014

(No "dead threads" here! If this page isn't currently on the Hotline your Q, A, or Comment will restore it)

Q, A, or Comment on THIS thread -or- Start a NEW Thread

Disclaimer: It's not possible to fully diagnose a finishing problem or the hazards of an operation via these pages. All information presented is for general reference and does not represent a professional opinion nor the policy of an author's employer. The internet is largely anonymous & unvetted; some names may be fictitious and some recommendations might be harmful.

If you are seeking a product or service related to metal finishing, please check these Directories:

Chemicals &
Consult'g, Train'g
& Software

About/Contact  -  Privacy Policy  -  ©1995-2024, Pine Beach, New Jersey, USA  -  about "affil links"