This is the inorganic technology lab again, metallography exercise. We did our best to produce some nice pictures without wasting too much SiC and diamond [2]. This post is mainly to show those pictures. I am not going to cover the whole chemistry. But remember we are not van der Voort [3].
Here's (globular grey) cast iron
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjWIkC7W2shJQiWb1A20AbCY6EfOmT-vfe4rqTZinK0LJHa1ydak1iUzIqnM4olSdkdXTxSLEF0yrtpBIx2wbIg53_Ylas7e1bp0srgDmzDV-yqQG0WzjTPjhDJuD9B-nB9H_AqqYv4wT0/s400/2-GG-1-0050_kl.jpg)
and here's a steel (at a higher magnification, etched with FeCl3).
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj1rYZChPhCO0VlRBBrswLlgr4pOVYDX-JUykbw2P-4JFKQ5H0OT1mrX9CtTG9TRjK68LCZSXuciKVNu60n18PPxAPDY9VBgP0XCHwODvtB30o_eJY500tRkv5gs8Psvzvs7SGyHivr9nM/s400/2-M300-3-0500-FeCl3_kl.jpg)
We etched the cast iron with nital solution (nitric acid in alcohol). You can see that there are three areas: carbon spheres, carbon depraved ferrite around them and a third one which is a mixture of ferrite and and cementite called ledeburite or perlite.
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgtAJRyL-i6AiHhL387W0srQZSgHM1HW7GJNVxmB0h5Ji4SRcJQluZWMZ4owb9CM_jA4IYNpNu-iaeNX1ljike6NXkAofiuWtqAWubgOVweF5kWvcujZQk70dpHfChepbJ-RbDClxKuse0/s400/2-GG-4-0200-Nital_kl.jpg)
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEig0FU8m-e9VRmXkwkJGmGRJrFaHCFYsj3SxTBp7VWGazE4bROvZJviXek7O12L1-3SDpla9lC0q2XqjFzLbkiFS8_lQBll14EVpdz7mVyYciy6QE7xJakxrw_ex2DayLGZxGtC-BPDDR0/s400/2-GG-5-0500-Nital_kl.jpg)
This is a copper alloy (4% tin, 4% zink, 4% lead). We etched it with FeCl3.
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhW3xkFqnMd7oDChmA9uBzDe5HgO969TkSvMdlXjNc5RdMHPcZAvv6wWkEVztlvPYV_uEqSCY-If4X8YBml0Dzw2d8H6buICRVaC_w0iygOAVaZqS3ylh-ApzdpzOE3kyAlBO_8IhWElmM/s400/2_Cu+4_0200_FeCL3_kl.jpg)
You can see typical twin crystallites in there.The grey spots are lead that is not miscible with copper in the solid phase.
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjsElnJdVlEsSQCiR0hyphenhyphen0TFVvTDUSY7vc-N7nydExsodxTwYOjm637xmDTJc4pN5osKsxUd4QzTQWZ4E0aXjN0eSy_job7Zuz23_5hHTGu2dQavVlKtEV8IW9dzi14j3DVLtsCMtpTPOSE/s400/2_Cu+5_0500_FeCL3_kl.jpg)
[1] I don't think it is possible for me ever to remember every part of a blast furnace.
[2] Actually "diamond" sounds better than it is. One carat of it which goes for something like 15,000 Euros if used for jewelry, costs less than a Euro if you produce it industrially.
[3] Van der Voort is the man when it comes to metallography. He has never taken a foto with a scratch.
1 comment:
Stunning...makes one realise that there is beauty around us not just in the form of all those organic molecules, but also metals.
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