| |
G6KUI > TECH 27.05.06 01:16l 33 Lines 1358 Bytes #999 (0) @ WW
BID : 7388_G6KUI
Read: GUEST DL1LCA
Subj: Resistivity of Chromium
Path: DB0FHN<DB0THA<DB0ERF<DB0ROF<DB0ACH<DB0PKE<DB0RES<DK0WUE<7M3TJZ<ZL2BAU<
GB7MAX<GB7DBY<GB7DBY
Sent: 060526/2340z @:GB7DBY.#23.GBR.EU NPF2.54c [G6KUI PMS Alvaston Derby]
A lot of questions have been asked about the resistivity of Chromium and
to why the published figures vary so much.
Why does anyone want the electrical resistivity of Chromium ? and in
what form is the Chromium that they want the resistivity of ?
Chromium is not usually used by itself except in chronium plating and then
it is a VERY thin layer and not usually by itself. If onto Steel, then
there is a copper layer and then a nickel layer and then finally the chromium.
Electroplated chromium is very porous and the porosity is very varied which
could explain the varying resistivity - the more holes, the higher the
resistivity.
Thin films of Chromium that are deposited on a ceramic substrate have very
interesting electrical properties. If heated (slightly) and cooled, the
resistivity changes and on cooling does not return to what it was before it
was heated. You have to heat it upto above 500degC before you get a stable
resistance at room temperature.
Chromium is usually used as an alloying element to other metals to improve
their oxidation resistance and/or their staining/corrosion resistance.
Hence stainless-steel , but that's another mine-field for the novice
because there isn't just one type of stainless steel , something like 7
basic types all of which are completely different.
73, Pete G6KUI
Message sent with NPFPMS V2.54c
Read previous mail | Read next mail
| |
