问题 问答题 简答题

简述适合于电镀制品的超硬材料具备的性能以及镀前超硬材料处理的必要性。

答案

参考答案:

(1)适用于电镀制品的超硬材料应具备的特殊性能:

①晶形和强度:晶形应规则完整,起码是等积形块状结构;强度应是MBD以上的中强度和高强度的品种。

②粒度组成:要求比较严格,希望增大基本粒的百分比,减少粗粒和细粒,尤其尽可能减少最粗粒和最细粒。

③表面状态:最好表面粗糙化,镀前必须经过表面净化和亲水化处理。

④磁性杂质:必须使用弱磁性磨料,减少磁性杂质对电镀制品的影响

(2)电镀前超硬材料须进行处理的原因:

一是要表面净化以除去杂质。

二是要除去表面上单分子吸附层,以便颗粒能亲水并沉积到基体上。

二者都是为了增强镀层与磨料间结合力。

阅读理解

A Frenchman went to a small Italian town and was staying with his wife at the best hotel there. One night, he went out for a walk alone. It was late and the small street was dark and quiet. Suddenly he felt someone behind him. He turned his head and saw an Italian young man who quickly walked past him. The man was nearly out of sight when the Frenchman suddenly found that his watch was gone. He thought that it must be the Italian who had taken his watch. He decided to follow him and get back the watch.

  Soon the Frenchman caught up with the Italian. Neither of them understood the other's language. The Frenchman frightened the Italian with his fist(拳头) and pointed at the Italian's watch. In the end the Italian gave up his watch to the Frenchman.

  When he returned to the hotel, the Frenchman told his wife what had happened. He was greatly surprised when his wife pointed to the watch on the table. Now he realized that by mistake he had robbed the watch and it was the Italian's.

小题1:The Frenchman went to a small Italian town _______.

A.alone

B.with his wife

C.with his friend

D.with an Italian小题2:The Italian gave up his watch to him at last because ________.

A.he had stolen the watch from the Frenchman.

B.he understood what the Frenchman wanted

C.he had picked up the watch on his w ay from work

D.he was afraid of the Frenchman小题3:Who was robbed of the watch on earth?

A.The Frenchman was.

B.The Italian was.

C.Both of them were.

D.Neither of them was.

判断题