Scientists in northwest China have doubled the service life of high-temperature, high-pressure artillery barrels by refining a chromium plating technique first used by the Chinese military before 200BC.
Bronze swords buried with the Terracotta Army of China’s first emperor, Qin Shi Huang, remained sharp and untarnished after more than 2,000 years underground.
Microscopic analysis revealed a thin layer of chromium salts – just 10 to 15 micrometres thick – on their surfaces, protected by an…
