several coating layers

• 复合涂层

several coating layers的用法和样例：

例句

1. The producing and using status of the raw material powder system of every cermet composite coating technique has been reviewed.
   金属陶瓷复合涂层技术作为重要的材料表面处理技术和材料复合技术能够制备各种特殊功能的涂层材料。