Need help making a high temp pigment

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The discussion revolves around developing a high-temperature pigment for products operating above 1000°C, with a focus on using graphite as a base. The current dye, Shepherd 10K927, is effective but limited to 1200°C, while Shepherd Black 444 has caused issues in solution stability. The engineer seeks advice on adjusting the pH from acidic to a neutral range of 8-8.5, potentially through an alkaline wash or mixing with an inert base. Concerns about graphite oxidation at high temperatures and alternative options like Iron II Oxide for stability are also highlighted. The engineer is optimistic about testing new formulations soon.
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I'll spare y'all the details but, in short, instead of previous plans I'd had, I've ended up doing exciting engineering work for a company in Virginia. Our products operate in very high-temperature environments (>1000C) routinely and we like to dye them black for visual appeal. As we look towards higher temp applications, our current dye will be insufficient. I'm looking to utilize graphite as the base of our pigment but, the pH is too acidic (~5, needs to be closer to 8-8.5). I'm an engineer, and not the colloidal chemistry kind. Would a simple alkaline wash be sufficient to maintain the desired pH? If I were to mix with an inert base material so that the average pH were in that 8-8.5 range, would that achieve the sort of results we're looking for? I apologize for the likely amateur questions but, I forgot all of ORGO the moment I finished the final exam.

Thanks in advance for any help y'all can provide!
 
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What is the base material ?
What was the previous dye ?
 
Baluncore said:
What is the base material ?
What was the previous dye ?
It'll be sprayed on refractory bricks and/or stainless steel. Previous dye was Shepherd 10K927 (pH 8.2) and it works well but, is limited to ~1200C. We've attempted Shepherd Black 444 (pH 6., slightly larger particle size) but, it caused everything to fall out of solution.
 
Graphite is an inert material at standard temperatures, but in the presence of oxygen, when the temperature reaches approximately 1000°C, the graphite will rapidly oxidise to CO or CO2.

Black 444 is used in applications where the absence of chromium is needed. Stainless steel contains at least 11% Cr, so you could use a Cr based pigment, or chemically convert the Cr surface of the stainless steel to a stable black compound.
 
Iron II Oxide. It is the black coating that you find on steel fasteners. Very stable at high temperatures. Can turn into red rust if you let it get wet. But the high temps will roast it back to black.
 
Would like to thank you all for your pointers! I've got a couple of prospectives going into testing on Monday. Fingers crossed but, I'm hopeful.
 
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