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topic 14164

Ruthenium/Iridium coated Titanium anodes




An ongoing discussion from 1996 through 2015 . . .

(1996)

Q. I'm looking for an anode resistant to corrosion in aqueous media and at high voltage (25 - 50 volts). For example, When proceeding to electrolysis of water, a relatively inert anode which also has some good electric properties is required. I am looking for that kind of anode.

Vincent Caron
University of Sherbrooke - Quebec, Canada


(1996)

A. Platinum or Graphite. Platinum clad mesh materials go for about US$5.00/square inch. The Metal Finishing Guidebook lists several sources for both materials.

Good Luck,


Dave Kinghorn
Chemical Engineer

SUNNYvale,
   California



(1996)

A. You can try activated titanium electrodes, this is titanium covered by ruthenium and/or iridium oxide. This is also known as DSA (dimensionally stable anode) material.

Another possibility is Ebonex.

Regards,

Frank Vork
- Eindhoven, The Netherlands


(1996)

Q. I've heard that titanium covered with ruthenium and/or iridium oxide is a very expensive technology. I'm looking for an anode with a surface area of about 200 square cm.

Vincent Caron [returning]
University of Sherbrooke - Quebec, Canada



(1997)

RFQ: Our company is based in Malaysia and we are involved in plating of leadframes. We are presently looking for a vendor to plate iridium oxide on our titanium anodes. We plan to convert all our platinum anodes to Iridium oxide coated Titanium anodes.

Nick Lim
- Malaysia
^- Sorry, this RFQ is outdated
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(1997)

A. Hello Nick,

Typically this process is done via vacuum methods, or by plating of Ir then thermal oxidization. Do you actually want reduced Iridium or the Oxide exposed? I am interested in understanding why you choose the Oxide? Also, are these platinum anodes that you will replace with IrOx/Ti located in your high-speed cells or your low speed flood cells? Using it in your high speed cells may introduce a severe design constraint into your cell tooling designs. I am sure if you contacted Technic, Inc. they will put you in contact with someone that they supply Ir to.

Regards,


Dave Kinghorn
Chemical Engineer
SUNNYvale,
   California



Ruthenium

Properties of ruthenium oxide and iridium oxide coatings

(1998)

Q. I am searching for the electrical and corrosion properties of ruthenium oxide and iridium oxide anode coatings intended for the electrodeposition of cationic coatings.

Paul R. Kerr


(2000)

Q. Dear Sir,

We are looking for the RESISTIVITY of IRIDIUM OXIDE ( IrO2 ). Many thanks for an answer on this subject.

Sincerely yours.

Jean-Michel.DESVIGNES
Lab. CHARLES FABRY de l'INSTITUT d'OPTIQUE - Orsay FRANCE


(2000)

A. The electrical resistivity of our IrO2 films is about 40 micro-ohm-cm (which compare well with that of single-crystal bulk IrO2). this particularly answers the questions of Jean-Michel.DESVIGNES from Lab. CHARLES FABRY de l'INSTITUT d'OPTIQUE and Paul R. Kerr.

-We have developed a new physical process to coat virtually any surface (Titanium is an excellent substrate with highly conductive and dense IrO2 films with an excellent adherence (Appl. phys. Lett. 69, (1996) 2027) . So this is a direct response to the Nick Lim - Malaysia.

- These iridium oxides have been tested for some specific corrosion studies and they have exhibited excellent corrosion resistant behaviors. Other applications are currently under evaluation.

Prof. My Ali El Khakani
Université du Québec / INRS - Energie et MatÈriaux / Varennes, QuÈbec, Canada



How iridium coating is done

(1999)

Q. I need information on how to coat Iridium on Titanium anodes. I am trying to coat a spring finger on a rack that is involved for plating.

James J. Sezemsky



(2001)

Q. I am studying about DSA for chlor-alkali industry. I know that they are mostly made from titanium coated with titanium oxide - ruthenium oxide.

My question is this: How is the way of coating this DSAs? and what are the salts used in the coating? I will be thankful if you can guide me.

Yours faithfully,

Mohammad Abedi
- Tehran, Iran


(2007)

A. Platinum group metals are deposited on titanium via thermal decomposition methods. For the most part, any form into which you can fabricate titanium, can be coated.

Depending on application requirements, the coating composition and loading can be altered for better performance.

Iridium oxide or iridium oxide/tantalum oxide mixes are quite common and perform well in a broad variety of applications.

For chlorine generation, mixtures containing ruthenium oxides are typically preferred due to higher yield (i.e. better specificity).

Barry Martin
Siemens - Union, New Jersey



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Ruthenium or Iridium Oxide coated Ti anodes in electro-coating

(2002)

Q. I am looking for information on the use of Ruthenium or Iridium Oxide coated Ti anodes in electro-coating. Why are expanded metals used in this type of anodes? One would think it would be difficult to have complete coverage of the expanded metal. I'll appreciate hearing from someone with experience or knowledge in this area.

Thanks,

Paul Lim
- Toronto, Canada


(2002)

A. RuO and IrO are what we refer to as DSA (Dimensionally Stable Anodes). They are used when one or all of the following conditions exist.

1) Very high current densities (greater than 5 amps/SF up to 12 amps/SF)

2) Concern for good UV durability on cationic acrylic tanks. As you experience soluble iron contamination greater than 20 ppm from parts or iron dissolution from stainless steel anodes that leak or overflow from plugged return lines, the UV durability will drop off rapidly.

3) Cationic color control tanks. Cationic tanks whether or not they are acrylic or epoxy can benefit in color control if you minimize the potential for dissolved iron from entering the paint bath from fallen parts or iron dissolution from stainless steel anodes that leak or overflow from plugged return lines. RuO is about twice the price of stainless steel and IrO is even higher yet. The RuO and IrO material are brushed on to a titanium anode. These hold up extremely well, but they can be prone to corrosion if the RuO layer is scratched.

Gurvin Singh
Coatec India
supporting advertiser
Mohali, Punjab, India



(2002)

A. Ruthenium and Iridium Oxide coated mesh type anode is suitable for electrolysis of chlorates and caustic soda anodes. It weighs light and surface area is more. You can operate 2KA/m2 suitable. Coating adherence is not a problem for mesh type anodes. Iron will deposit in the anode while power cut and will inactivate your UV system.

R.Nagarajan
Chennai, Tamilnadu, India


(2003)

A. Expanded metal is a very efficient form of titanium to use in developing an anode. For example, if the mesh pattern has about 50% void area, the surface area is the same as for a solid sheet, even though half the titanium material is used. The cost of expansion is markedly less than the material savings for an expensive material like titanium.

The coatings are applied as salt solutions and the baked in an oven to convert to oxides. Various proprietary methods are used by manufacturers to prepare the surface for the coating and to control the thickness and uniformity of the coating to assure proper quality. Coating uniformity is not perfect, but depending on the manufacturing method, it can be quite good.

Coating loading effects life, but unless the area effected is large, the current discharge would shift to a nearby site that is still active. The titanium would form a passive film that would not breakdown and pass current. In most applications, the majority of the coating would have to fail before titanium substrate failure began.

Barry L. Martin
- Concord, Ohio



Seeking IrO2 Coated Anodes

(2003)

RFQ: We are a service looking forward to supplying below product to our good customers. Kindly offer your quotation as below. Titanium Mesh Dimension: W250mm x L640mm x T1 mm, with Iridium Oxide coating as an insoluble plating anode. Life time: in pulse mode of rectifier, Fw120A / Rev240A(current density 120ASF) can last for 6000 hour. General need: 600~1000 pieces per year. If any question please let me know. We are looking forward to receiving your response soon.

Mika C
plating service - Taiwan [last name deleted for privacy by Editor]
^- Sorry, this RFQ is outdated
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To minimize searching and offer multiple viewpoints, we combined multiple threads into the dialog you're viewing. Please forgive any resultant repetition.



Mixed Metal Oxide Coating (MMO) on Titanium Dimensionally Stable Anodes (DSA)

(2005)

Q. The electrolytic chlorine generation industry and the "grounding" industry associated with galvanic corrosion both reference a Mixed Metal Oxide or MMO coated Titanium electrode. The metals referenced are NIOBIUM, PLATINUM, RUTHENIUM, IRIDIUM, etc. Does anyone have any details on this MMO coating and the process involved in producing this MMO coating? In addition, there seems to be new technology out there emerging which allows the polarity of the anode and cathode to change without damage to the coating. All info would be appreciated.
Thanks,

DAVID LEECH
- Batesburg, South Carolina


similarly (2006)

Q. I need the detailed information about how the mixed metal oxide coating on Titanium mesh.

SK.Gajalakshmi
- Theni, Tamilnadu, India


(2006)

Q. I need the detailed information about how the mixed metal oxide coating on Titanium mesh/plate.

John Wong
- Shanghai, China


(2006)

RFQ: We are interested in buy some anodes plated with the IrO2 coating, 50 square meters.

TONNY [last name deleted for privacy by Editor]
plating shop - Longgang, Shenzhen, China
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April 6, 2009

Q. How to coat the Iridium & ruthenium oxide with titanium metal.

aparna sivalingam
production manager - Coimbatore.Tamil Nadu, India


April 6, 2009

Q. DSA. We need to coat the mixed metal oxide like Ir, Ru Oxide coating technologies.

regards

vijayakumar shanmugam
student - coimbatore.tamil nadu, India



Issues with anodes for chloride zinc plating bath. How long do anodes last?

July 29, 2008

Q. We are using iridium coated anodes in our chloride zinc plating bath. After 3 weeks the resistance started going up and the current flow started down. I checked them with x-ray florescence and found the iridium is still there but I am now showing chrome also. I had a problem with chrome contamination around the same time. Could chrome immersion plate on the surface of the iridium and would it stop the current flow?

Chuck Beckerdite
captive plating shop - Versailles, Missouri, USA


A. Hi Chuck. Chrome should not immersion plate on your anodes because iridium is a noble metal. Although such anodes can be used as auxiliary anodes to reach low current density areas, I'm not familiar with doing zinc plating with only such anodes. Where does the zinc come from if not from zinc anodes?

But chrome can really mess up a plating process. I'd suggest doing some Hull Cell testing to see if the plating solution has been successfully decontaminated and will plate properly. Good luck.

Regards,

pic of Ted Mooney
Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey
Striving to live "Aloha"



Hydrogen Production

Hydrogen production vs. surface area

May 29, 2009

Q. Formula needed: I want to have Titanium Plates coated in Iridium for Hydrogen production in distilled water using a non caustic Electrolyte. What is the Electrochemical formula for the amount of hydrogen produced, by the amount of square inches of plate or mesh size, by the amps used?
Is there one?

Plate size example:
2.75" x 8" plates , 8 solid plates, or 8 mesh plates?

Howard R. Groves
- Eldersburg, Maryland


June 4, 2009

A. Hi, Howard. I don't think there is a formula for amount of hydrogen per square inch -- I think that's an empirical number based on the construction details. But I think that the amount of hydrogen per amp-sec should be predictable by Faraday's Law of Hydrolysis, which says that 96,487 amp-seconds will release 1 gram equivalent weight.

Regards,

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



April 11, 2012 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

Q. I am looking to bring Iridium coating in house. It is currently out sourced to a company that I believe is brushing it on. The material we are coating is Titanium and it is an anode structure.

I am not having much luck finding techniques or information on the topic. I think the people doing it now are roughing the surface then painting a coating on it, which is bluish (I believe IrO). Then I believe it is being baked in an oven.

Any help would be appreciated.

Steve Haasman
- Dayton, Ohio, USA


May 18, 2012

A. The substrate is sand blasted and pickled for the removal of scales. A paint of isopropyl alcohol with the metal chlorides along with titanium tetra chloride is painted by brush with no metal parts. It is baked in oven at 400 to 600 degrees. Painting and baking done many times to achieve the desired thickness. If wear resistance is needed iridium chloride is added, if catalytic action is needed ruthenium chloride is added, for water electrolysis, more platinum chloride is added. If high current density is required niobium is added. As far as I know.

Ganesanbala Chandran
- Chennai, India



Paints or pastes for coating Ti electrodes with Ru and Ir Oxides

July 6, 2015 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

Q. We use Ti electrodes in electrolysis of salt solution. We need to coat the Ti with ruthenium and iridium oxide. Any suggestions about how to do it will be greatly appreciated.

Vinod Sikka
Product Designer - Oak Ridge, Tennessee, USA


September 3, 2015

My understanding is that one applies the Ru or Ir to the CLEAN Ti surface as the appropriate nitrate. By CLEAN I mean totally free of oxides. One does this by treating the Ti with a nitric/HF or nitric/NH4HF2 pickle. Right after rinsing, you paint the precious metal nitrate on. Then, bake, to something like 400 °C.

After baking, you may with to add more nitrate solution, you might wish to do this a few times. On the final baking cycle, cool the coated metal electodes rapidly. One wants a certain amorphous nature in the coating; that helps the catalytic activity.

There's lots of literature out there about this technology. Such electrodes are commercially known as DSA - dimensionally stable anodes.

My knowledge of this is rusty. This is some stuff I did 20 years ago. I tried, not having any Ru or Ir, to coat my anodes with a mixed oxide of Ni and Co. I got a nice adherent coating, but the catalytic activity was disappointing.

dave wichern
Dave Wichern
Consultant - The Bronx, New York



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