Amcrom chromium copper

例句：

1. 1.The steel is made from chromium and iron.
   这种钢是由铬和铁制成的。
2. 2.Chromium is a rare metal that is used in many industrial processes.
   铬是一种稀有金属，用于许多工业过程中。
3. 3. Chromium compounds are often used as catalysts for chemical reactions.
   铬化合物常被用作化学反应的催化剂。