Tingroom Radio—不锈钢为什么不生锈？（下）

 The best way to avoid rust¹ is to use stainless² steel. Like all steel, stainless steel is mostly iron, but it also contains nickel and chromium. These are not just a protective coating, but are melted into the steel itself. The mixture must contain at least ten percent chromium, because it’s the chromium that protects stainless steel from corrosion³. What happens is this: Like a sacrificial metal, the chromium rusts⁴ first. Unlike iron however, rusting⁵ chromium doesn’t crumble⁶ apart. Instead, it forms an invisibly thin layer that protects the iron underneath⁷. The nickel in stainless steel helps hold this protective layer of chromium rust in place. Remember that chromium and nickel are present throughout stainless steel, not just on the surface. Because of this, the microscopic⁸ layer will form itself anew, even when the steel is cut or scratched.

1 rust   

n.锈；v.生锈；(脑子)衰退

参考例句：

• She scraped the rust off the kitchen knife.她擦掉了菜刀上的锈。
• The rain will rust the iron roof.雨水会使铁皮屋顶生锈。

2 stainless   

adj.无瑕疵的，不锈的

参考例句：

• I have a set of stainless knives and forks.我有一套不锈钢刀叉。
• Before the recent political scandal,her reputation had been stainless.在最近的政治丑闻之前，她的名声是无懈可击的。

3 corrosion   

n.腐蚀，侵蚀；渐渐毁坏，渐衰

参考例句：

• Corrosion is not covered by the warranty.腐蚀不在保修范围之内。
• Zinc is used to protect other metals from corrosion.锌被用来保护其他金属不受腐蚀。

4 rusts   

n.铁锈( rust的名词复数 )；（植物的）锈病，锈菌v.（使）生锈( rust的第三人称单数 )

参考例句：

• Copper nails are better than iron nails because the iron rusts. 铜钉比铁钉好，因为铁会生锈。 来自辞典例句
• The axenic culture of rusts has been achieved on various defined media. 在各种规定的培养基上可得到锈菌的单体纯净培养物。 来自辞典例句

5 rusting   

n.生锈v.（使）生锈( rust的现在分词 )

参考例句：

• There was an old rusting bolt on the door. 门上有一个生锈的旧门闩。 来自辞典例句
• Zinc can be used to cover other metals to stop them rusting. 锌可用来涂在其他金属表面以防锈。 来自辞典例句

6 crumble   

vi.碎裂，崩溃；vt.弄碎，摧毁

参考例句：

• Opposition more or less crumbled away.反对势力差不多都瓦解了。
• Even if the seas go dry and rocks crumble,my will will remain firm.纵然海枯石烂，意志永不动摇。

7 underneath   

adj.在...下面，在...底下；adv.在下面

参考例句：

• Working underneath the car is always a messy job.在汽车底下工作是件脏活。
• She wore a coat with a dress underneath.她穿着一件大衣，里面套着一条连衣裙。

8 microscopic   

adj.微小的，细微的，极小的，显微的

参考例句：

• It's impossible to read his microscopic handwriting.不可能看清他那极小的书写字迹。
• A plant's lungs are the microscopic pores in its leaves.植物的肺就是其叶片上微细的气孔。