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INTRODUCTION
- Lesson 3 - Surface Coatings and Heat Resisting Alloys
Surface
coatings are often sufficiently thick that you can resolve their
metallurgical microstructures. What is different is that the
transition zone between the coating and the substrate is often quite
thick and is affected by imperfect wetting, heat flow, diffusion, or
other invasion of the substrate by the coating metal. |
| The
photomicrographs made by me of these
miscellaneous specimens in the M.I.T. collection all illustrate heat resisting alloys. Their microstructures range from quite simple to rather complex, but they often show transition type behavior due to interactions with their environments, similarly to the coated metals. |
| Allow plenty of
time to study and to take good notes about each specimen. About
two hours per lesson would be appropriate. You will be expected
to interpret some of these specimens during the final
examination. Feel free to use the Internet to find additional
information about the alloys and applications mentioned here. |
| Whenever the
narrator asks a question, be sure to commit yourself to an answer
before going to the next page. You can backtrack with your
browser's BACK button at any time, of course. Just be sure to click
the FORWARD button to return to the proper page before proceeding so
that you don't get lost. |
| FIRST
SPECIMEN |