david french

Re: Basics of Electroplating

David C. French, Vice President of PRO-pHx Technical Services
President of David French & Associates, Inc.
Phone 704/607-0191 - 336 Orchard Circle  - Charlotte, NC 28217
FAX 704/731-0775 - davidfrench@pro-phx.com
www.PRO-pHx.com                                                           3-24-2006

    Electroplating Basics

Electroplating is an electrochemical process by which metal is deposited on a substrate by passing a current through a bath containing the desired metal(s). Usually there is an anode (positively charged electrode), which is the source of the material to be deposited; the electrochemistry that is the medium through which metal ions are exchanged and transferred to the substrate to be coated; and a cathode that is the component (the negatively charged electrode) to be coated. Plating is done in a bath that is usually in a non-metallic tank (usually plastic). The tank is filled with electrolyte that has the metal, to be plated, in ionic form. The anode is connected to the positive terminal of the power supply. The anode is usually the metal to be plated (assuming that the metal will corrode in the electrolyte). For ease of operation, the metal is in the form of nuggets or balls and placed in an inert metal basket made out non-corroding metal (such as titanium or stainless steel). The cathode is the workpiece, the substrate to be plated. This is connected to the negative terminal of the power supply. The power supply is well regulated to minimize ripple current as well to deliver a steady predictable current, under varying electrical loads such as those found in plating tanks. As the current is applied, positive metal ions from the solution are attracted to the negatively charged cathode and deposit on the cathode. As replenishment for the deposited ions, the metal from the anode is dissolved and goes into the solution and balances the ionic potential. In the case of materials such as gold, the anode is not sacrificial (gold does not dissolve easily!), but it is made out of material that does not dissolve in the electrolyte, such as titanium. The deposited gold comes out of the solution. Plating is an oxidation-reduction reaction, where one material gives up electrons (gets oxidized) and the other material gains electrons (gets reduced). The anode is the electrode at which oxidation occurs, and the cathode is the electrode at which reduction occurs.

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ENAM

Re: Basics of Electroplating

Hi Members ,
I am doing  research on Hard chrome plating with Trivalent chromium. It seems to me that it has limitation but there has been progress in getting some good results. It would be appreciated if any one has  latest idea or development in this area.
ENAM

Southern Metal Finishing

Re: Basics of Electroplating

ENAM wrote:

Hi Members ,
I am doing  research on Hard chrome plating with Trivalent chromium. It seems to me that it has limitation but there has been progress in getting some good results. It would be appreciated if any one has  latest idea or development in this area.
ENAM

[color="DarkSlateBlue"]Hello ENAM,

I recently met a gentleman named David Ventola at the AESF Washington Forum.  He is VP of Operations at a company in Medford, MA called Xtalic.  Xtalic is doing research on a Nano-Technology that will replace hard chrome and I found our discussion very interesting.  See below.....

>>>Xtalic’s new technology is a highly reproducible electrodeposition method for producing precisely-tailored, ultra-hard ‘nanocrystalline’ metal coatings. These coatings have an impressive suite of desirable properties, including high strength, long-term stability at elevated temperatures, high integrity (i.e. no cracking), excellent corrosion resistance and a pleasing natural luster. The coating process is robust, allowing coatings to be deposited with uniform, controlled thicknesses ranging from micrometers to millimeters, and with microstructures tailored at the atomic level to allow easy customization of coating properties for specific applications. Multiple patents have been filed to protect the technology underlying Xtalic’s deposition process.

Hard Chrome Replacement
With the coming regulatory changes, hexavalent-based processes such as hard chromium plating need to be replaced with more environmentally-friendly alternatives. Our coatings’ unique combinations of properties and processing advantages make them a natural replacement technology for hard chromium plating, without the environmental baggage of hexavalent chromium. Please contact Xtalic to learn more about our revolutionary new technology. <<<

We hope to publish an article on this technology in Southern Metal Finishing in the future, but you should give them a call.  I think you will find the conversation equally as interesting as I did.

Paul Fisher, Editor
Southern Metal Finishing
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Southern Metal Finishing's Website

ENAM

Re: Basics of Electroplating

Hi Members ,

It would be highly appreciable if anyone could provide information about latest developments on Trivalent hard chrome plating.

ENAM

Southern Metal Finishing

Re: Basics of Electroplating

"3"

Southern Metal Finishing's Website

atiquetipu

Re: Basics of Electroplating

hi every body

Dedalus

Re: Basics of Electroplating

Trivalent chrome plating - for the latest, try contacting one of the vendors.

MacDermid has these:

MacDermid Industrial Solutions

My personal knowledge of this process is a few years old. The system I saw required multiple additives, and a separate anolyte segregated from the rest of the bath by an ion selective membrane. There were also issues with the color not matching that obtainable from traditional hex chrome solutions, a critical matter in decorative automotive applications.

However, Science marches on big_smile and some or all of these problems may have been solved.

Dedalus Environmental - The On-Site Treatment Specialists

Dedalus's Website

DustinGebhardt

Re: Basics of Electroplating

Dedalus wrote:

The system I saw required multiple additives, and a separate anolyte segregated from the rest of the bath by an ion selective membrane. There were also issues with the color not matching that obtainable from traditional hex chrome solutions, a critical matter in decorative automotive applications.

You can also use inert anodes which are made from sheets of titanium coated with iridium.  They are pretty pricey as I recall.  However, the bath usually behaves better with these anodes versus the lead-acid boxes.  And you are right about the color.  When I was on the other side of the vendor/buyer fence, I've had some potential customers turn my shop down due to the subtle, but still present, color difference between tri and hex based baths.

-Dustin Gebhardt,
CEF
Plating Engineer
Danaher Tool Group
Gastonia, NC