In a cooperative project, University College London and Terracotta Army Museum researchers have published a study in Scientific Reports that sheds light on a forty year old mystery of why Terracotta weapons have not degraded over time as would have been expected.
The thousands of fantastic life-sized warriors in the Terracotta Army of Xi'an were armed with fully functional spears, lances, hooks, bows and arrows.
While the organic portions of these weapons such as wooden shafts and scabbards have deteriorated with time, the bronze components are in far better condition than they should be.
This was originally thought to be due to an ancient anti-rust treatment that was akin to modern chromate conversion coating technology, but the researchers indicate chrome found was due to a lacquer not even applied to the weapons
The terracotta warriors and most organic materials of the mausoleum were coated with protective layers of lacquer before being painted with pigments - but interestingly, not the bronze weapons.
We found a substantial chromium content in the lacquer, but only a trace of chromium in the nearby pigments and soil - possibly contamination. The highest traces of chromium found on bronzes are always on weapon parts directly associated to now-decayed organic elements, such as lance shafts and sword grips made of wood and bamboo, which would also have had a lacquer coating. Clearly, the lacquer is the unintended source of the chromium on the bronzes - and not an ancient anti-rust treatment.
The local soil composition, high-tin content of the bronze, and quenching technique were cited as contributing factors in the weapons' remarkable preservation.
Bronzes buried in Xi'an soil remained almost pristine after four months of extreme temperature and humidity, in contrast to the severe corrosion of the bronzes buried for comparison in British soil.
The researchers note that although their research largely explains the mysterious longevity of the weapons, there may still be a mysterious Qin Dynasty weapon preservation process in play as well, so further investigation is warranted.
Surface chromium on Terracotta Army bronze weapons is neither an ancient anti-rust treatment nor the reason for their good preservation (open, DOI: 10.1038/s41598-019-40613-7) (DX)
(Score: 5, Funny) by Runaway1956 on Friday April 05 2019, @02:48PM (9 children)
It's called "discipline". The terracotta army cleaned their weapons, according to regulation, after every use.
(Score: 4, Touché) by The Mighty Buzzard on Friday April 05 2019, @03:00PM (8 children)
Nah, it was just back when Made In China didn't mean "this is complete crap that is going to break after three hours of use".
My rights don't end where your fear begins.
(Score: 2) by pkrasimirov on Friday April 05 2019, @03:27PM (6 children)
In Southeast Asia "Made in China" means exactly the opposite. Merchants push their wares forward saying "It's good, from China!"
(Score: 3, Funny) by curunir_wolf on Friday April 05 2019, @08:01PM (3 children)
I am a crackpot
(Score: 0) by Anonymous Coward on Saturday April 06 2019, @11:03AM (2 children)
It's a pity millions of kiddies were afflicted with lead poisoning as a result
(Score: 0) by Anonymous Coward on Saturday April 06 2019, @11:06AM (1 child)
Chinese baby milk powder blamed for 50 deaths [theguardian.com]
(Score: 1, Funny) by Anonymous Coward on Saturday April 06 2019, @02:47PM
See?!? This is what happens when you don't use real baby in your products.
Now, let's talk about their Baby Oil
(Score: 0) by Anonymous Coward on Friday April 05 2019, @09:37PM
"Made in Japan" and "Made in Korea" are the goods to get. "Made in China" is ... serviaceable, one step below, say, "Made in Vietnam".
(Score: 2) by driverless on Sunday April 07 2019, @02:23AM
That's because it's being compared to "It's, um, OK, made in Bangladesh".
(Score: 2, Interesting) by Anonymous Coward on Friday April 05 2019, @09:42PM
Back around that time, the most advanced civs were the Chinese and the Persians. The Greek Alexander pulled the Mongols (i.e., conquered a lot, didn't stick around), and it was a time before the Romans.