[TheForge] weapons found with the terracotta army

[Bruce .]

My first suspicion is that they'd happened upon a high-chromium ore,
much as folks in the middle east happened upon a high-vanadium ore for
making Wootz (sp?) steel.  I don't know whether that makes sense
either metalurgically or geologically.

However, there is a general tendency for the current generation to
discount the intelligence and knowledge of past generations.  (This
was not always so.  Witness the tendency in the middle ages to harken
back to the Greeks and Romans as fonts of knowledge.  I suspect it's
the old pendulum, swinging back and forth....)  I expect that many, if
not most, of us in this group are less inclined to think this way, but
it's easy to fall into the trap.

China (as a whole -- which it wasn't always) was a great empire, for
thousands of years.  It traded with the middle east, so goods and
knowledge were exchanged.  It is more than likely that crude batteries
were known in the middle east, and it has been suggested that these
were used for electroplating (precious metals IIRC).  Of course,
ferrous metals were fairly well explored, possibly better than we
realize (because they rust and aren't well represented in the
archeological record), as were copper-based alloys.

I'd be really surprised if the ancients had aluminum or titanium due
to the electro-refining needed to produce those metals.  But certainly
any metal that can be refined by reduction with carbon seems likely to
have been in their possession -- if not in pure form.

 The South American natives (of whom the Incas are but the last
empire) treated copper-gold alloys repeatedly with heat to "burn off"
the copper on the outside, leaving gold-colored items they valued for
their non-corroding beauty.  Could the same be done with a
chromium-steel alloy?  Isn't that essentially what we do when we
passivate SS with a nitric acid pickle?  Mind you, I don't know that
that would work, I'm only speculating.

On Wed, Jun 13, 2012 at 1:13 AM,  <blakkpawss at yahoo.com> wrote:
> Here's some thoughts I had.  1) you describe the chromium layer as though it was a coating.  Like a plate job.  Is it possible that something like a plate job was used to coat them?
>
> 2) this was an honor guard for an emperor if I'm not mistaken, right?  If so, they would have been outfitted with the best or most beautiful weapons available.  No cost would have been spared. If a sword smith had said we can make them really shiny and pretty by coating them with (X), then (X) would have been gathered from all over the Chinese empire to fill that goal.  So, it might have been for looks more than durability.
>
> 3) if it was for durability then they were smart smiths.  This could be possible.  They might have known how to do it, but reserved it for royalty, due to the time, labor, and cost.  After all, as I understand it, most people view Japanese swords as the high mark for the craft, most archeologists and historians think that most of that knowledge was stolen/borrowed from the Chinese.
> Sent from my BlackBerry® smartphone powered by Alltel
>
> -----Original Message-----
> From: "terry l. ridder" <terrylr at blauedonau.com>
> Sender: theforge-bounces at mailman.qth.net
> Date: Tue, 12 Jun 2012 22:25:10
> To: theforge e-mail list<theforge at mailman.qth.net>
> Reply-To: "terry l. ridder" <terrylr at blauedonau.com>,
>        Blacksmithing List Sponsored by ABANA <theforge at mailman.qth.net>
> Subject: [TheForge] weapons found with the terracotta army
>
> hello;
>
> i have been reading about the terracotta army in china and the
> excavation work that has and is still going on. in reading about the
> weapons found with the terracotta army many questions come to mind. many
> of the swords found are still 2,000 yrs later still sharp and corrosion
> free. they have a 10 to 12 micrometer layer of chromium oxide on the
> blades. i find it hard to believe that the swordsmiths in china 2,000
> yrs ago had any knowledge of chromium or chromium oxide. was it just
> chance that the metals they were using to fashion the swords was
> contaminated with just the right amount of chromium to provide corrosion
> resistance that has lasted 2,000 yrs?
>
>
>
> --
> terry l. ridder ><>
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-- 
Bruce
NJ