Nickel coatings with boron-nitride, mold release coatings

A. Hi Giorgio. In general there are the particles, a surfactant or wetter for the particles, perhaps thixotropic agents to help keep them suspended for occlusion into the deposit, and the electrolytic or electroless nickel plating solution, which itself may have a number of ingredients. The incorporation of particles into electrolytic and electroless nickel deposits is the subject of numerous patents, so you might try a patent search. There are a lot of trade secrets involved, so everything will not be fully available, but I think the licensors of such technology can help you with the properties of the deposits. Take a look at some vendors' website, like Surface Technology, and see if they answer some of your questions. Good luck.

"Electroless Plating"
by Mallory & Hajdu

on eBay or

AbeBooks

or Amazon

(affil links)

A. Plain electroless nickel might be all you need. If not good enough, then a composite of same with teflon is more expensive but is the best you can get for rubber molds. Chrome could also help a bit, but it is difficult to polish and will not get into deep recesses, grooves, etc.

A. The Electroless-Nickel/Teflon coating is an ideal surface treatment for mold release especially for plastic injection molding, but I have heard it doesn't work for rubber injection molding due to temperature restrictions. We are in the process of evaluating a co-deposit of Electroless-Nickel with particles of Boron Nitride. It provides the same co-efficient of friction as Nickel-Teflon, but can withstand extreme temperatures and it has a chrome like hardness.

A. Is the rubber "real" or synthetic? Years ago some tire molds were plated with EN for release and the adhesion was perfect. Synthetics seem to be ok with EN. We did some molds for fan belts some years back with EN and a Teflon baked coating that worked well. I don't think there is such a thing as a "permanent" mold release.

A. Dear Hasan,

You can add silicon carbide and boron nitride in hypophosphite reduced electroless nickel plating baths to prepare the Ni-P-SiC and Ni-P-BN composite coatings. However, there are several factors such as particle size and shape, relative density of the particle, particle charge, inertness of the particle, the concentration of particles in the plating bath, the method and degree of agitation and the orientation of the part being plated that govern the incorporation of second phase particles in the Ni-P matrix.

Besides, electroless plating baths are highly susceptible for decomposition in presence of foreign bodies. Hence the baths used for preparing composite coatings should have suitable stabilizers.

A recent review on electroless Ni-P composite coatings is published in Journal of Applied Electrochemistry 33 (2003) 807-816. You may want to have a look at that.

A. Hi, Taher. I don't think you can convert an acidic electric nickel bath to an alkaline bath by simply raising the pH. I think you would need to use an alkaline electroless nickel bath. I could be wrong, but I think the ZnO will rapidly convert to ZnOH at that pH. I don't have much confidence in being able to co-deposit ZnO particles in your electroless nickel bath, but I've been wrong before :-)

Regards,

A. Upul,
Spray from aerosol can like Pam.

A. Victor B,
Would BN (boron nitride) work for you?

? Hi Chris. You are speaking of electroless nickel phosphorous plating with boron-nitride particles, right?

Regards,

Correct on all.

A. Hi Rehan. CBN abrasive particles can be occluded into nickel electroplating, electroless nickel plating, or chromium plating. As the nickel or chrome is deposited onto the substrate, the particles are incorporated into the metallic deposit and the metal grows around them, locking them in place. I don't think it's possible to electroplate CBN by itself because it's non conductive.

This plating process is not easy to do because the particles must stay suspended in proximity to the parts and not get blown away from it either; I understand that a good fluidized bed design to keep them in suspension plus special wetting agents are required to do this properly. Consequently most of this technology is licensed rather than being available as published generic information.

CBN particles can also be "glued" onto the substrate with resins. The adhesion is not as good because encapsulating a particle in solid metal will always be more secure than any adhesive; but if this is just for a better manual grip, for example, surely an adhesive will be sufficient, and to my understanding is much cheaper.

Luck & Regards,

A. Hi again Rehan. Sorry, I don't actually know how to do either of those processes. I realize that business works differently in Pakistan and the USA, but very few people in the world actually know the details of this, and only after many years of experimental work ... and they license the technology, i.e., you pay them a certain amount per month, or per piece that you want to plate, and they give you all the details, the necessary surfactants, and the necessary technical help, etc.

If you go to https://www.surfacetechnology.com you will see how this generally works. They are one of the suppliers who license this technology. There may or may not be a consultant or company in Pakistan or India or the mideast who can help you. Good luck because you will need it if you hope to do this type of electroless plating without licensing the technology from someone who already knows how to do it.

Luck & Regards,