On Sunday, July 27, 2014 4:07:27 PM UTC-4, Peter M wrote: > > Ah, I see. I am a semantics person too so I appreciate the clarification. > On Jul 27, 2014 4:06 PM, "Steve Palincsar" <pali...@his.com <javascript:>> > wrote: > >> On 07/27/2014 04:01 PM, Goshen Peter wrote: >> >> So what does brass do, is just called patina? >> >> "corrosion" >> >> On Jul 27, 2014 4:01 PM, "Steve Palincsar" <pali...@his.com <javascript:>> >> wrote: >> >>> On 07/27/2014 02:17 PM, Goshen Peter wrote: >>> >>>> Beautiful but how it says they don't rust, one of the nice parts of a >>>> brass bell is watching it age and oxidize, and the sound is so unique. >>>> >>> Not to be pedantic or anything (nobody would ever be pedantic on this >>> list) but since rust is iron oxide, brass does not rust. >>> >> The desired word here is 'tarnish'. In this case, dealing with brass, it is an oxidation process. As Steve pointed out, rusting is the oxidation of iron; tarnishing is the oxidation of copper or brass. (Though to be precise, a tarnish can form with other than 'oxidation'; if instead of oxygen, it was sulfur dioxide, or for silver, hydrogen sulfide... well, there's the whole reducing environment versus oxidizing environment... say, if you have available iron in an an oxidizing environment, yes, you can have hematite or magnetite forming (Fe2O3 or Fe3O4), but if it's a reducing environment, you end up with pyrites (FeS2, etc.) instead.
One difference: a tarnish is happening on the surface, and can form a 'protective' layer for the underlying metal. A rust, like a normal 'red' rust, can continue to see ongoing oxidation of iron. (However, it is possible to get a 'black rust' to act as a tarnish, and keep the underlying iron from rusting. ) -L (a geologist, trying to remember his chemistry....) -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To unsubscribe from this group and stop receiving emails from it, send an email to rbw-owners-bunch+unsubscr...@googlegroups.com. To post to this group, send email to rbw-owners-bunch@googlegroups.com. Visit this group at http://groups.google.com/group/rbw-owners-bunch. For more options, visit https://groups.google.com/d/optout.
