Chemical Vapour Deposition CVD

A. Chemical vapor deposition (CVD) is used extensively to coat carbide metal cutting tools with TiN. Deposition temperature depends on the chemical reaction used. For hard coatings, deposition temperatures are on the order of 1100 C. I would think that a chemical plating process or physical vapor deposition would work much better for your application.

A. Dear Mats,

In 1986, a Toronto company built a facility for the chemical vapour deposition of nickel and other metals and alloys (NVD). The major use of the NVD technology was to deposit ultra pure nickel (99.99999% -- yes!) onto a substrate. The deposit ranged from a few microns to over 1" thick. The thickness was uniform to ± 0.001"(even in corners),there was no nodular growth, and the dendritic structure of the pure nickel was extremely even and regular. The hardness of the nickel was about 20 RC, which could be increased to almost 50 RC by doping the nickel lattice structure. The most amazing thing about this technology was that it duplicated the surface of the substrate on an atomic level. You literally got an exact duplicate of whatever the substrate was, thus class A finishes, delicate engraving, etc. was exactly duplicated.

Large scale facilities were built in Sudbury, Ontario (1989) and for a German company in 1997. A machine shop in Midland, Ontario claims to have a small NVD chamber. CVD Manufacturing bought out and now operate the plant in Toronto.

The NVD technology was a development from the original Mond process (used in nickel ore refining), and was also used by an American company which unfortunately doesn't exist any more. The US and UK nuclear industry also experimented with NVD in the 1950s.

I was VP of Marketing for the company until it was bought out, so I am somewhat familiar with the history of this technology :)

When I saw your posting on copper plates, I remembered that we deposited NVD nickel on copper plates for printing applications.

I hope this information is of use to you.

A. Dear Sir,

I have worked in the semiconductor industry and am familiar with the plating of various metals via CVD technology. There are several pitfalls associated with this type of deposition namely film structure, cost and equipment. Commercial semiconductor equipment is very expensive. Older equipment can be purchased from an auction company or from an equipment refurbisher. The modern equipment is very sophisticated and requires a highly skilled person to operate the equipment. The older equipment can yield excellent results if a trained individual is operating the equipment as well. In addition a university working on semiconductor films may have a home brewed piece which will also work. CVD is a very substrate dependent surface. The surface must be clean from inorganic as well as other organic contaminants. A considerable knowledge of the film to be deposited and the substrate needs to be known for excellent results. If the film grows too fast it may flake off or if the film is too highly stressed the film will also flake off. The films growth rate and structure can be influenced via a number of techniques. CVD can be used for a number of metals see "The Chemistry of Metal CVD" by Kodas and Hampden-Smith. This is an excellent reference book on metal CVD.

A. Dear Mats,

Eventually I found your letter here and probably you already found what you were looking for. If not, shall the plates you have be protected all around or just on one side? Also what thickness are you looking for ? There are some open issues. Nickel, in the Nickel Vapor Deposition process, does not adhere to the deposition substrate, but it can be made to adhere.

There are erroneous statements in the responses, such as the uniform thickness of 0.001" even in corners, or the grade of purity is 99.99999%. The "machine shop in Midland, Ontario, who claims to have a small NVD chamber", actually now has a large state-of-the-art NVD plant with a deposition capacity of 200t of Nickel per year.

Hi, Thomas.

Thanks for the update on the production capacity of the machine shop in Midland! You asserted that two other statements were false, but didn't offer new details to replace them. Could you please try to provide us with replacement numbers or facts, so this technical discussion does not devolve into "is NOT" ... "is TOO" ... "is NOT" ...   :-)

Regards,

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

A. It's really not possible to give you a definitive answer without details of the coating process, the coating composition, and the coating characteristics -- thickness, residual stress, et al. Rainbow can be caused by contamination during the coating process or if the coating is too thin. The dull appearance could be the result of the coating being too thick, or not dense enough.