Sound technical content, curated with aloha by
Ted Mooney, P.E. RET
Pine Beach, NJ

Need Pickle Inhibitors, Rodine and alternatives

Q. We just found out that Henkel is only allowing 55 gallon drums to be bought. That would last us 10 years. Does anyone know of an alternative to Rodine 213?

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I am interested whether experience exists relative to the use of organic amine based acid inhibitors in HCl pickling baths used in electrogalvanizing operations. In particular, I am interested in whether use of such inhibitors in the pickling bath would create problems with adhesion or other deleterious surface problems. The concentration of inhibitor would be ~0.06% (wt) in the HCl pickling bath used for activation of the surface just prior to plating.

 1996

Kindly provide the list of chemicals which are used for pickling bath process.

Durant: Proprietaries like Henkel's Rodine series, or Stannine, or Parkin are used in acid pickling of steel. Topic 7046 gives some general ideas about the basis of these inhibitors. The acid activation step immediately before electroplating is not really an acid pickling step, although platers sometimes call it that. I don't think inhibitors are needed for these short & mild acid activation processes, and I suspect that your implication that they could cause plating problems could be correct.

Ketumin: Hot sulfuric acid or cold hydrochloric acid plus inhibitors would be the most common for steel; nitric plus hydrofluoric would be common for stainless steel. Please try to rephrase your question a bit less abstractly and I'll try to help!

RFQ: Our company is going to deal with cleaning of various types of equipment. We need to buy these chemicals and preferably someone from India. Suppliers for these inhibitors:

Amchem Rodine 31
Amchem Rodine 213(L)
Armohib 28
Armohib 25

RFQ: Dear Sir

Please quote 6 Jerricans of 25 kg Rodine A213, Stat. No. 3824909999.4039

If you have any question, do not hesitate to contact me.

Best Regards,

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 note: Sorry, this RFQ is old & outdated, so contact info is no longer available.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?)

RFQ: I am using sulfamic acid and sodium erythorbate to clean shell side heat exchanger with 300 ss tubes I need a Rodine inhibitor for this

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 note: Sorry, this RFQ is old & outdated, so contact info is no longer available.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?)

RFQ: Respected sir,

I am searching for unique supplier for Rodine( HCl Inhibitor ) since long.

I got your reference with the help of surfing. I need to know about Rodine technology and scope of supply.

Regards

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?)

Q. Hello,
My company has a unique use for stainless where we bond elastomeric coatings to the surface. The chemistry and physical structure of the surface as received from the mill can have a profound effect on the strength of bonding. Most of the mills use a combination of HN03 and HF in the pickling process. I understand that boron is used as an inhibitor. I was wondering if you could confirm this and share with me any of the other inhibitors that are used. Many of these inhibitors would likely lead to bonding issues if not fully removed. Thank you for your help.

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. Hi Thomas. Pickling inhibitors are interfacially-active compounds which bind to the steel as monomolecular layers and shield it, reducing the attack on the steel. They may contain both organic and inorganic ingredients -- commonly alkenes, alcohols, amines, polymerized aromatics, and heteroaromatics. But that's all I know :-(

We ask people to please help via citations to published works rather than personal knowledge. There are many proprietary inhibitors offered by Rodine, Akzo, Stannine LTP, and others, but the formulations are trade secret. If a person unknown to us offers information about their composition, we have no way of knowing that they are an independent researcher with personally developed knowledge or a disgruntled employee trying to devalue someone else's intellectual property :-(

Luck and Regards,

Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

A. Thomas,
It sounds like you may be better off finding pickling compositions that don't cause problems for you, and specifying on your purchase orders that only those compositions may be used.

The other problem with bonding this, that, or the other thing to stainless steel is how non-reactive the passive layer tends to be. I guess it depends on the coating, some things need the surface to be activated, some things work better if the surface has been very well passivated, and for some things it doesn't matter much either way. I wonder if that's a factor with your coating.

Ray Kremer
Stellar Solutions, Inc.

McHenry, Illinois