On March 1, 1994, the world-famous eighth wonder of the world, the second pit of the Terracotta Warriors and Horses of Qin Shihuang, officially started excavation. This is one of the great archeological discoveries since this century.
A bronze spear, a copper crossbow machine, a copper cymbal, and a residual sword have been unearthed in the pit of No. 2 figurine. Among them, a group of bronze swords with a length of 86 cm have been found. The sword has eight edges. Archaeologists measured with vernier calipers and found that the error of these eight faces was less than one hair, and 19 bronze swords have been unearthed. The internal structure of these bronze swords is dense, the blade body is bright and smooth, the blades are fine-grained, and the textures come and go. Researchers found that the surface of the sword had a 10-micron-thick chromium compound. This discovery immediately caused a sensation in the world, because this chromium salt oxidation treatment method is an advanced process that only appeared in modern times. Germany in 1937 and the United States invented and applied for patents in 1950.
While clearing the first hole of Pit No. 1, archeologists found that a bronze sword was bent by a pottery figurine with a respect of up to 150 kilograms, which was bent more than 45 degrees. When people removed the pottery figurine, A shocking miracle appeared: the narrow and thin bronze sword rebounded straight and recovered naturally in an instant. The shape memory alloy dreamed by contemporary metallurgists turned up in ancient tombs more than 2,000 years ago.
In fact, the method of oxidizing chromium salts was by no means an invention of the Qin Shihuang era. As early as the Spring and Autumn and Warring States Periods, the Chinese mastered this advanced process.
During the Spring and Autumn Period of the Five Bullies, the King of Gou practiced scratching the guts and defeated Wu Wangfucha in one fell swoop, performing the last scene of the Spring and Autumn Hegemony in history. The passage of time has made this thrilling war quietly sleep in the long scroll of history, and its busy descendants have almost forgotten it.
However, when an archeological team excavated the Spring and Autumn Tombs, they accidentally found a long sword covered with dirt, and a line of ancient swords on the sword—the “Yuewang Goujian Sword” jumped into people s sight. This major archeological discovery immediately made a sensation throughout the country, but more sensational news came from scientific research reports on ancient swords. The first thing that attracted researchers attention was: why this ancient sword has been buried in the ground for more than 2,000 years, why hasn t it rusted? Why is it still cold and sharp? Through further research, it was found that the reason why the Yuewang Goujian Sword was millennium stainless is that the sword was coated with a layer of chromium-containing metal. As we all know, chromium is a rare metal that is extremely resistant to corrosion. The chromium content in the earth s rocks is very low, and extraction is very difficult. Furthermore, chromium is a high-temperature-r esistant metal with a melting point of about 4000 ° C.
There have been too many secrets in Chinese civilization. Who could imagine that the scientific invention of the 1950s would have appeared more than 200 BC? Who can imagine that the sword that Qin Shihuang s soldiers wielded is a masterpiece that has not yet been invented by modern science? The question is, what attitude do we use to explain this super-conventional premature technology after discovery? We really don t want to see some people use incidental to explain, it should have a more specific explanation. If the above facts are true (at least the chromium salt oxidation treatment is not false), then we will ask: What is their technical origin?