secondary mullite

例句：

1. 1.The secondary mullite is used in the production of high-quality ceramic tiles.
   次级莫来石用于生产高质量的陶瓷瓷砖。
2. 2.The secondary mullite was found to have excellent thermal conductivity.
   次级莫来石被发现具有极好的热导率。
3. 3.The secondary mullite has been widely used in the field of ceramic engineering.
   次级莫来石在陶瓷工程领域得到了广泛应用。