What metals/alloys used in antiquity last the longest and/or resist deterioration the longest?
The ancient metals would seem to be copper, tin, (both togther as bronze), zinc (alloyed with copper as brass), lead, iron, gold, and silver.
Gold would seem to be the best since it is so resistant to corrosion. The silver coins salvaged from shipwrecks always seem to have corroded into a nasty clump. A bronze cannon I saw at the Mary Rose Museum looked like it was practically new while the iron artifacts from the same wreck were much worse off.
What kind of effect does climate have? Wet jungles would seem to corrode metal quicker than deserts, but is that the case?
Alchemic texts referred to Gold as “imperishable Gold”, thus implying that your original assumption was correct.
Looking back, I don’t think I asked what I really want to know. When an archaeologist digs up ancient metal artifacts, what which kinds are metals are likeliest to have survived in good condition?
Metals resist corrosion in relation to their order in the Galvanic or Electrochemical series.
I’m not a metalurgist, but I think there are some more factors to consider. Your link refers to metals in seawater. Some metals that might corrode quickly when exposed to salt and water might last much longer in a desert.
Other things to consider are:
(1) some metals may oxidize quickly, but form a protective oxide coating in doing so. Some metals form oxides that are good barriers to further corrosion (Cu), while others do not (Fe - rust flakes away and otherwise isn’t much good in this regard).
(2) Some metals corrode especially quickly when in electrical contact with each other. (This is the galvanic corrosion mentioned in the above link.)
Also, I don’t believe that zinc was discovered (as a separate metal) until a few hundred years ago, although brass (its alloy with copper) was known much earlier.
So of the metals that you list, I thinks it’s clear that gold would last the longest, and iron would likely corrode the quickest in most environments. Silver, lead and copper (and copper alloys) also last fairly well, mostly because of the protective coating issue I mentioned. (silver tarnish is a fairly good barrier, although that’s a sulfide, not an oxide).
But I’m sure someone with more detailed info will be along soon.
Oh yes, there are. Soil pH, oxygen levels, temperature, presence of metal salts, sulphides, oxide layers etc. all affect corrosion rates. The electrochemical series is a measure of how reactive a metal is under standard conditions. It’s useful for generalizing about a metal’s stability, but of course the precise conditions that a metal is stored under has big effects on its stability.
Pure gold is the clear winner, if we’re talking about chemical deterioration, but if there’s any sort of mechanical wear, it’ll be one of the first to go. So that’s another factor to consider. It’d be a lousy choice to make your booby-traps out of to menace Indiana Jones millenia later.
I really ought to have a better answer, but I’ve seen very well-preserved bronze and silver coins, as well as very badly preserved bronze and silver coins. I would suspect factors like where it was left (eg, Egypt vs. Britain) makes the biggest difference.