Mechaton - 17-10-2006 at 21:13
I'm interested in making some Strontium ferrite for BIG transformer cores. Anybody have any info on how it's made? I'm having trouble getting good
resources.
If anyone knows of an easier to make or obtain core material I'd be interested in hearing about it.
12AX7 - 17-10-2006 at 22:11
Should be something like, make a slip or whatever of ball-milled SrO and Fe2O3 (as SrFe2O4? Not to suggest spinel of course, as I recall spinels only
form with the smaller ions i.e. Mg, Fe(II), etc.). A gum binder or such will be needed since this isn't clay. 99% purity should be good. Press or
cast to shape, dry, and sinter (fire) to something just below the melting point.
I didn't know strontium ferrites were used. I have heard only transition metals like manganese and zinc. I forget which ones are the hard ferrites
(i.e. ceramic magnets).
Overall this is going to be more trouble than buying, especially if you want a 100kW core or something. It'll take days to fire something that big
without cracking, and you just don't have the process control, chemical or thermal, that industry has.
If you do go through with this, I would love to get a sample of a typical product though!
Tim
Mr. Wizard - 17-10-2006 at 22:12
You can get Strontium Nitrate from red road flares, although I'm sure it's not pure. You'de have to remove the oils, the wood flour and the Sulfur.
tumadre - 18-10-2006 at 00:17
the temperatures required are very high,
I would say use what is already avalible, grind it up and use a small amount of binder and fire it, or grind into power and mix with epoxy, but that
would be like a powerded iron core, not what you want?
not_important - 18-10-2006 at 00:19
having troubles getting my reply to post, trying fragments
hmmm, it looks as if
http://www.hoosiermagneticsinc.com will sell ferrite powders
not_important - 18-10-2006 at 00:22
while making them is discussed in many places, including
http://www.blackwell-synergy.com/doi/abs/10.1111/j.1151-2916...
http://cat.inist.fr/?aModele=afficheN&cpsidt=13664922
http://www.springerlink.com/content/b866j67715625473/
Either precipitation or prolonged ball milling, if not both, looks to be needed. Also appears than firing at 600 to 1200 C is needed.
not_important - 18-10-2006 at 00:27
and the last URL, after finding one to the same reference, and that doesn't choke the forum software
http://www.ingentaconnect.com/content/ap/cs/2001/00000236/00...
tumadre - 18-10-2006 at 00:43
even if you achieve %85 or %90 the density achieved by the same ferrite product produced by industry, the magnetic properties will be vastly
different.
so unless there is nothing fundamentaly different between industry and DIY ferrite production, your not going to have good magnetic qualities.