> I UNDERSTAND THAT SILVER NITRATE WILL DECOMPOSE AT ABOUT 444C. I'M > TOLD SILVER IS VERY ACTIVE WITH MOST CERAMICS, BUT IT'S A LITTLE > CONFUSING THAT THE CRC HANDBOOK SAYS THAT SILVER OXIDE WILL GO TO > SILVER METAL AS LOW AS 230C. WHO AMONG US KNOWS WHAT THE HECK IS > HAPPENING WITH THE SILVER AT 600? THAT'S THE TEMP WHERE CARBON BURNS > OFF.
My gut tells me, Reid, that if you want to take your blackened filters and fire them high enough to burn off the carbon, that your silver deposits would not be harmed. If you're saying that silver oxide will go to metal at 230, I'd say you'd still have metal at 600. The only thing(s) happening as you go up in temp will have to do with evaporation of the metal and any interaction with the substrate material. There, we're talking about some sort of alumina or other ceramic materials... I shouldn't think you're looking at a serious problem. However, it'd sure be nice to cut out a bunch of steps... I wrote: > Would it be worth a try to mix the dry clay with CS or a silver > nitrate solution instead of water, and testing the resulting material > for germicidal activity? > > MIXING WITH THE CLAY, AND NOT SATURATING WITH THE FIRED CERAMIC > MEDIUM, MAY CARRY A WHOLE DIFFERENT SET OF PROBLEMS. FOR ONE THING > THERE WILL HAVE BEEN NO BONDING BETWEEN ADJACENT CLAY PARTICLES, WHICH > HAPPENS AT UPPER TEMPERATURES. CERAMISTS CALL THIS PHENOMENON 'SPOT > WELDING' FOR WANT OF A BETTER TERM. THE PERMEABLE MEDIUM FOR A PILE > OF CLAY PARTICLES WOULD BE QUITE DIFFERENT. No, I was saying to hydrate the dry clay with your silver preparation rather than plain water, whether high ppm CS or silver nitrate solution. (I'm assuming you're starting with a dry clay, either powdered in bags or dried after being dug from the ground.) Cast and dry the silver laden slip, then bisque fire... to your 1050C or whatever it was... Now you've got silver atoms floating around affecting the vitrification process of the raw clay, but again, the only difference between 600C and 1050 is some additional evaporation and whatever interactions take place with the substrate as it forms. Your oxides and nitrides would be long gone, probably. Yes, there's lots of unknowns, but I hope the experiment would be easy enough to do to be worth the effort... Given the *extremely* easy process that would result. Once you have some test pieces, you could test for effectiveness just like you do for the current ones. You could also look for somebody out here to sponsor some analyses... metalography, electron microscopy, Auger spectroscopy... to tell you if you've got silver embedded in your matrix, how much, and what, if anything, it's bonded to. Is there anything to lose in trying? Be well, Mike D. [Mike Devour, Citizen, Patriot, Libertarian] [mdev...@eskimo.com ] [Speaking only for myself... ] -- The silver-list is a moderated forum for discussion of colloidal silver. Instructions for unsubscribing may be found at: http://silverlist.org To post, address your message to: silver-list@eskimo.com Silver-list archive: http://escribe.com/health/thesilverlist/index.html List maintainer: Mike Devour <mdev...@eskimo.com>
