Crude Flame Fusion of Al2O3+Cr2O3, Synthetic Ruby Test cooling down.
3,481 views · Published 7 March 2018 · 0:47 · Indexed 6 October 2026
Channel: Matthew Wilson · 2018 · Howto & Style
I've been testing with refractory materials to create extreme temperature ceramics for a Verniuel furnace I'm designing. I'm at various stages of testing concepts and I've found creating the initial starting boule isn't incredibly difficult. The synthetic ruby I've created takes approximately 8 solid minutes under 2200 Celsius constant heating with a MAPP/Oxy torch. As stated, these are very crude, but it proves it is possible to use a crude setup and reach the necessary temperatures to fuse alumina. I mixed approximately 1.2% by weight, of chromium oxide with aluminum oxide. I took around 30 minutes to prepare the oxide mixture by grinding and thoroughly mixing 44 micron oxide powders with an agate mortise and pestle. I'm also working with titanium dioxide and alumina to form sapphire. I've found that doping the aluminum oxide with 3% by weight of titanium oxide, produces a mid-blue boule. I started filming the video after about 25 seconds had already passed cooling down. I'm quite sure these synthetic gems have all kinds of stress fractures due to a lack of appropriate cool-down cycle. They do however scratch glass, so I'm pretty sure that's about a moh's hardness of 8 to 8.5.--I need to double check that.
