Sam or Mary Yancy on thu 10 apr 08
I really don't know - but is it only iron that causes overheating in a microwave appliance? I have a RED glaze cup that will boil coffee in about 30 seconds in the microwave and be too hot to handle. Will a microwave do the same to other metals - perhaps LEAD?? Which is/was used in glazes awhile ago. I love the cup but will I GLOW over time??? Is there anybody out there who is a expert on this?? Sam in Daly City
J A Fugate on fri 11 apr 08
I passed the glaze in microwave question along to my son, who is a geochemist, and this is the brief response that I got:
hmmm... microwaves work by exciting dipolar molecules like water. It's much more efficient at heating substances where the molecules are free to move, like water, than substances that are solid, like a glaze. Generally, the reason a dish like a plate, mug, pot, etc. gets hot is that it is heated by the food or beverage that is actually being heated. So, i'm not exactly sure why one glaze would get hotter, but maybe the microwave is heating water in the air, which is heating the pots by convection... and since metals are very good heat conductors, perhaps the pot with free iron (in metal form, even if microscopically) would naturally get hotter because of the ability to conduct heat. Additionally, molecules with Fe might be dipolar, which could be affected by the microwave radiation, which would in turn cause them to get hotter. I'm not really sure, these are just guesses...
Sam or Mary Yancy wrote:
I really don't know - but is it only iron that causes overheating in a microwave appliance? I have a RED glaze cup that will boil coffee in about 30 seconds in the microwave and be too hot to handle. Will a microwave do the same to other metals - perhaps LEAD?? Which is/was used in glazes awhile ago. I love the cup but will I GLOW over time??? Is there anybody out there who is a expert on this?? Sam in Daly City
______________________________________________________________________________
Clayart members may send postings to: clayart@lsv.ceramics.org
You may look at the archives for the list, post messages, change your
subscription settings or unsubscribe/leave the list here: http://www.acers.org/cic/clayart/
Moderator of the list is Mel Jacobson who may be reached at melpots2@visi.com
__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com
Ivor and Olive Lewis on sun 13 apr 08
For those who are interested in this topic.
I had a look through the CRC compound lists and in Greenwood and =
Earnshaw
1. None of the Iron compounds containing Phosphorus listed have red or =
orange colouration.
2. There is potential for free Iron to be created from iron oxides at =
temperatures as low as 700 deg C in a reducing environment.
3. Magnetite, FeO.Fe203, is a strongly magnetic mineral. It would form =
at atmospheric if Red Iron were heated above 700 deg C in a reducing =
atmosphere.
4.Electromagnetic radiation is influenced by a magnetic field. For =
proof, move a weak magnet across the face of a Television Screen.
Best regards,
Ivor Lewis.
Redhill,
South Australia.
| |
|
