Composite diamond electroplating

A. I know that at one time General Electric was offering these diamond particulates already nickel plated for easier occlusion but I'm not sure if they still do. This is a field which is quite highly developed and where numerous patents are in place. You might want to start with Surface Technology [Trenton, NJ] as they have specialized in this for decades.

A. I just read an article by this Surface Technology folks in the Jan. 2000 issue of Metal Finishing magazine. References also mention several patents.

? Hi Joel,

Are you looking to actually plate the diamond particles with EN for use in making abrasive tools such as grinding wheels, which as Ted points is a product that GE specializes in, or are you looking to coat a substrate with an EN/diamond composite?

A. Yes. The diamonds can be imbedded in either electroless nickel or electrolytic nickel. One approach would be to contact one of the patent holders like Surface Technology for a license.

A. Composite diamond is small diamond particles co-deposited with either electroless or electrolytic nickel, or any other suitable metal "binder". Electrolytic nickel is often preferred because of its control, but electroless can give better thickness distribution. The trick to getting a uniform distribution is to have sufficient agitation in the electrolyte to allow the diamond particles to slowly settle out onto the workpiece at a consistent rate.

A. To supplement Ted Mooney's response, the diamonds can also be embedded into nickel formed by the Nickel Vapour Deposition process. The technique we have used before, is to grow nickel on top of a graphite substrate (with diamond coating). Then that substrate is coated (by the vapour deposition process) to whatever thickness of nickel is needed.

The graphite can then be destroyed (e.g. by sand-blasting) to leave the diamonds embedded in the surface of the nickel.

Our process will grow thick nickel, with diamonds on the surface, to a depth of up to 2cm. In the CVD process, nickel will grow at the rate of 1mm thick in 4 hours.

We hope this helps.

A. The most common application of diamonds in nickel deposits is by nickel sulfamate solution.

A. Hello Nishant.

Basically, the diamond particles are embedded into nickel plating as the plating is conducted. The diamonds are suspended in the nickel plating solution and, as the nickel deposits, the diamonds are occluded.

Sometimes the diamond particles that you buy are already nickel plated. You need an agitation system (a fluidized bed) to hold the particles in suspension, probably a surfactant to properly "wet" the diamonds, and perhaps sometimes a thixiotropic agent is added to the solution to help maintain the suspension.

But most of the information is carefully guarded trade secret rather than generic information. You can obtain a license from Surface Technology in Trenton, New Jersey or another licensor of technology for nickel-diamond composite plating and they will tell you everything you need to know to do it. Your question, in a specialty that is very closely protected, is unfortunately a bit difficult to publicly discuss in very much detail.

Good luck!

A. Sorry that my advice did not work out for you, Nishant :-(
It's usually not a good idea to publicly comment on private contact with a third party -- because fairness demands that the readers hear the other side after they've been given the impression that the other party lacked the courtesy to respond :-)

There is not much I personally know about the technology. Diamond particles are suspended in a slurry of electrolytic or electroless nickel so that when the nickel deposits on the substrate, the diamond particles are occluded into the matrix as a composite coating. But what wetting agents are needed for the diamonds, and what thickening agents (if any) are used, and what sort of agitation system or fluidized bed keeps the particles in suspension, and what adjustments (if any) to plating concentrations, temperatures, voltages, and amperages are required, are closely held trade secrets. Good luck!

A. Nishant R,
Here's a little tip coming from a 21 year old then, been electroplating since I've been 14.

Knock down current "AMPs" before removing your plated item to reduce burning on the TIP's of your subject. If this is not done the carbon build up will cause the diamond and nickel bond to flake off after prolonged use.

Nishant R, that's one trade secret for ya.

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Ed. note: Thanks David!

A. Hi Thiyagarajan. What is your starting point? Do you know whether you want to use electroplating vs. electroless plating (very different chemicals). Are you already experienced in nickel electroplating or electroless nickel plating, and have the equipment and the diamond particles? Your quickest path, although maybe not the only path, is to obtain a license for this technology. Thanks!

Regards,

A. Here is a link to a study done in India for electroless plating of nickel and diamond. It provides ingredients, some methods and results.

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Ed. note: Thanks John!

A. Not really sure what you mean here - do you want to electrodeposit diamond onto a substrate? if so - it can't be done unless you use a diamond suspension and co-deposit it with a metal such as copper or nickel. If you want to coat an article with a diamond layer, you will need to use vacuum technologies. This is well documented by the razor blade industry, where virtually all good razer blades are now coated in a diamond like layer (DLC - Diamond Like Carbon). The trick here is to get sp3 deposits as opposed to sp2, which is graphite and much softer. The separation of sp3 and sp2 is usually done with a magnetron.