Who'd of thunk it? https://www.zypcoatings.com/top-selling-boron-nitride-coatings/bn-lubricoat-lubricoat-blue/ Best, Kelly
What did you have in mind for it, crucible coating? Tools? It sure looks like a useful product. Pretty high cost of admission though. The variations in listed service temps is interesting. Do you think its due to the presence/absence of O2? Pete
Yes, primarily metal tools used in molten aluminum contact. Skimmer, stirring rod, pouring cup/funnel, perhaps the furnace basin......and maybe a rotary degassing lance . I think it could be ideal for a steel crucible used in electric oven/kiln. But if you can afford this stuff you could probably afford a commercial crucible. I'm going to try coating my carbon thermocouple sheath with it because it gets wetted and coated with Al which drips off. I wouldn't care unless the drip landed on my resistive heating elements of my furnace. I think it may also greatly reduce the rate at which the carbon sheath is oxidized/reduced in air and extend life. At $1.25 each for gouging rods it's hardly worth it but drilling them for the TC is a bit of a pain. They actually have a SiC product just for protecting carbon and graphite. I was thinking you might be able to just coat an inexpensive metal sheathed TC and just skip the carbon sheath altogether. OIF says he gets 100 dips from his with no coating. I think I'm going to experiment with it a bit before I coat a clay graphite crucible. Starting every melt with a clean as a whistle crucible is appealing. I suspect it may be slightly insulating but as a thin layer, probably negligible. They offer another BN coating that is very hard and abrasion resistant .......albeit slightly lower service temp? https://www.zypcoatings.com/wp-content/uploads/Datasheet_BN-Hardcoat.pdf ......but my tools don't get banged around much and this product is supposed to be applied to the broadest range of substrates. No doubt. They're pretty proud of their stuff. seems like $200+/gal is there going rate for most things. It's probably a 2x Lifetime supply. If it works well it would be a good thing to share. I'm sure a gallon covers many square feet. I suspect that's right. The Lubricoat had a higher service temp than the hard coat which was another factor that swayed me towards the general purpose product. They offer this SiC product. A few others too if you click around on that page. https://www.zypcoatings.com/industrial/coverguard/#tab-id-1 Best, Kelly
I was researching cubic boron nitride abrasives and read an article on hexagonal boron nitride: very thermally conductive, good dry lubricant similar to graphite. It can be sintered so it would be possible to make a crucible out of nothing but boron nitride with a service temperature of 3000 deg C/5432 deg F .
Good to know Mark. I'll be tempted to coat the inside of a clay graphite crucible.....need to play with it a bit before doing so. Best, Kelly
