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Post by tileman2 on Nov 29, 2015 22:22:57 GMT -6
Jim;
I have read some articles about molybdenum transition metals before. Seems they can draw current in one direction, and pass current the other. If they get this perfected, the whole monitor, TV, cell phone screen images will change. It will make HD look like the old B&W days.
Evan:
Been reading up on transition metals properties: might have to rethink some of my formulation.
Tom
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Post by tileman2 on Dec 2, 2015 21:25:24 GMT -6
WARNING: Boring chemistry topic ahead.
Jim:
I came across the nugget I have been looking for for over two years: "the octet rule." The octet rule states: " All elements lose or gain electrons so they wind up with the same electron configuration as the nearest noble gas." ( noble gases are on right side of the periodic table.)
-So you can count to the closest gas to the element you are using- skipping over transitional metals. Metals will accept electrons and non metals will lose elections- although some exceptions to this rule apply.
-As it turns out in further reading: Moly has several distinct electrical fields within its molecular structure. Being a sulfate SO4/-2 ,so the glaze formula has to include elements that will donate at least (-2).
Tom
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Post by jfox on Dec 3, 2015 9:33:51 GMT -6
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paul
Junior Member
Posts: 51
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Post by paul on Dec 3, 2015 11:35:35 GMT -6
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Post by jfox on Dec 3, 2015 12:20:45 GMT -6
interesting note on so called noble gasses they are not as chaste as classical chemistry would lead you to believe you get them excited enough and they will couple ( like most of us) en.wikipedia.org/wiki/Noble_gas_compound |
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Post by evan cornish-keefe on Dec 3, 2015 13:23:59 GMT -6
So roasting MoS2 will create MoO3, but using MoS2 directly in a glaze the same transition wouldn't happen at the beginning of the firing?
I'm not understanding the reason to use barium, I haven't seen any crawling in my tests, and was under the impression that most of the sulfur burns away.
Is barium only important when using the disulfide form, and how much would you need?
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Post by jfox on Dec 3, 2015 14:33:20 GMT -6
 I think most of the sulfer would be gone at red heat,unless you kept it in reduction all the way up and that usually causes other problems my comments on moly sulphide are strictly academic unrelated to what we are doing here. that said i wonder if you sager fired or used an inert atmophere perhaps you could get some interesting developments en.wikipedia.org/wiki/Sulfide_minerals |
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Post by tileman2 on Dec 3, 2015 17:19:00 GMT -6
Evan:
Sorry, should of clarified that I am testing the sulfide form. The two test tiles that I show above are the exact same recipe: the only difference is colorants. The green has no barium additions, and the close up of the moly does. I am using barium carbonate at 2%, which I apply after the glaze coat is dry and the tile is warm. Being highly soluble it would just suck into the clay otherwise.
Paul: correction- the alkaline metals to the left react more closely to hydrogen in that they loss electrons easily. The noble gases are all to the right as you noted. The exceptions as Jim points out on the right is boron and silicon: which are insulators that donate electrons. The rest I do not care about because we do not use them in our glaze soup. Bought the remaining inventory of Nep SY today for .12ยข a pound. Stocking up for next spring launch...maybe, hopefully, if I have any energy left to do it.
Jim: the reason I bought the chemistry book. Chapter four is the octet rule, chapter five - ionic compounds with charts of exceptions. And chapter six covalent bonding with even more charts that list the exceptions. This crap will fry your synapses in a hurry trying to remember every rule and exception: so I cheated and bought a book with charts and graphs so I do not have to. The So4/-2 was referencing the sulfide in the compound- not the Moly element.
From chapter 5 "Ionic compounds consist of cations and anions that stick next to each other because their opposite charges attract." So the question of the day is: if oxygen anions are required for crystal development, and Mo has none: is SiO2 donating enough free radical oxygen anions to get the job done?
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Post by evan cornish-keefe on Dec 7, 2015 11:28:12 GMT -6
Hey Tom, are your tests only on horizontal surfaces? I got around to doing a few more tests, removing the iron and titanium from the glaze that was forming Mo crystals, and then a line blend swapping lithium for calcium. As the calcium increased I got more of these white blotches on a clear glass, they fluoresce under short wave UV light so I think they're Powellite.  I'm missing something...? More details on these tests: willemite.tumblr.com/post/134732115590/powellite-tests |
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Post by tileman2 on Dec 7, 2015 17:12:38 GMT -6
Evan:
I have done four test - tiles only. I have seen those white spots on test tile that had 7% lithium and 6% calcium. Mo is a rather unique element that has some rather bizarre oddities about it. Trying to calculate what will oxidize it the best. At this point I am thinking a different metalloid, in addition to SiO2.
Tom
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Post by evan cornish-keefe on Dec 19, 2015 13:00:00 GMT -6
So, I'm under the impression that the white splotches are Powellite, based on the way they fluoresce, though they look so different from the large iridescent shapes I'm aiming for. My thought at this point is that the silica and alumina in this glaze may not be ideal, since Powellite doesn't contain silica, there's no need for the high proportion like is used in other crystal glazes?
I'm not sure what you mean by what will oxidize it the best?
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Post by tileman2 on Dec 19, 2015 21:53:40 GMT -6
Evan:
Was using oxidizing in a very general sense: Redox is the transfer of electrons between two elements. SiO2 shares/donates oxygen atoms to ZNO to create zinc silicate. So the SiO2 oxidizes the ZNO... so I am wondering if there are other elements that would help to oxidize MO. The recipe for cone 10 is already known; cone 6 is another story.
Tom
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Post by jfox on Dec 20, 2015 9:46:47 GMT -6
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Post by evan cornish-keefe on Dec 20, 2015 15:52:38 GMT -6
Yeah, that's confusing!
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Post by jfox on Dec 20, 2015 16:32:48 GMT -6
i'm not sure anything is being oxidized or reduced in this equation
2 ZnO + Sio2=Zn2SiO4
Then again I failed that test in chemistry. Help!is there a chemist in the house
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