The scientists used the proton X fluorescence non-vacuum analysis method to perform non-destructive scientific testing on the Yue Wang Gou Jian sword, and found that the main components of the Yue Wang Gou Jian sword were copper, tin, and a small amount of Bronze alloys composed of aluminum, iron, nickel and sulfur. Tin is a metal with strong rust resistance. More importantly, the black diamond pattern of the sword body is vulcanized. The sulfur content is very high. Copper sulfide can prevent rust. rust.
In 1974, three swords were unearthed in the pottery pottery pit of Qin Shihuang, Lintong, Shaanxi. The sword body was bright and cold. When it was unearthed, it was not only rust-free, but also sharp enough to cut through more than 10 newspapers at once.
The surface treatment of these 3 Qin swords is more advanced than the Yue Wang Gou Jian sword. The ancients used the chromium salt oxidation method. Chromic hydrochloric acid is a very strong oxidizing oxidant. After the sword is treated with chromium hydrochloric acid, the surface oxide metal of the sword tightly covers the surface of the sword. Although this layer of stable oxidized metal is very thin, it puts a protective suit on the sword to prevent it from being rusted. In foreign countries, this chromium salt oxidation treatment technology began to be applied in the 1930s, and China began to apply it more than 2000 years ago.