Proceedings of the American Academy of Arts and Sciences, Vol. 47: From May 1911, to May 1912 (Classic Reprint) - Hardcover
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Excerpt from Proceedings of the American Academy of Arts and Sciences, Vol. 47: From May 1911, to May 1912
The crucible. - The ideal crucible for work on alloys would be one made from thin metal, if we could find some metal that would not diffuse, for we could then readily study the effects of chilling, as the crucible would be a good heat conductor. But since all metals diffuse, even in the solid state, we cannot hope for such a crucible. The best substitute would be one made from thin metal and lined with a thin coating Of lime.
The need for such a crucible has been felt by all who have attempted to make anything like an accurate study of alloys, and attempts have been made to perfect one, but until now without success. The author has finally succeeded in lining a steel crucible with a thin coating of lime. These linings are fairly durable so long as they are kept free from moisture, but if left in a damp place the lime slacks and cracks Off. With a lining two tenths Of a millimeter in thickness I have made seventeen melts, each time chilling in an ice-bath, and at the end Of this time the lining was almost intact.
These linings are made from a mixture Of finely powdered quick lime and calcium nitrate, about four parts by weight Of the lime to one by weight of the nitrate. Care must be taken that the powders are thoroughly mixed. Such a mixture fuses to solid lime when sufficient heat is applied to drive Off all the nitric acid.
This last fact is not new. It is Often made use Of in the chemical department of Harvard University for preparing small boat-shaped crucibles suitable for melting small portions of metal. But one meets with considerable difficulty in keeping the powder in place on the steep sides of the crucible while it is being fused.
The method finally employed is to use a cylindrical-shaped crucible. This is clamped, Open end outward, in the chuck of a high-speed lathe and then set spinning. The mixed powder is then carefully blown inside the crucible where the centrifugal force holds it firmly on the sides in the form Of an even coating. The spinning crucible is then heated with a blast lamp until all the acid is driven Off. It is then removed from the lathe, set in an upright position, and the bottom sprinkled with a coating of the powder. This is finally fused on, the force of gravity keeping the powder in place.
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Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com
This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.
The crucible. - The ideal crucible for work on alloys would be one made from thin metal, if we could find some metal that would not diffuse, for we could then readily study the effects of chilling, as the crucible would be a good heat conductor. But since all metals diffuse, even in the solid state, we cannot hope for such a crucible. The best substitute would be one made from thin metal and lined with a thin coating Of lime.
The need for such a crucible has been felt by all who have attempted to make anything like an accurate study of alloys, and attempts have been made to perfect one, but until now without success. The author has finally succeeded in lining a steel crucible with a thin coating of lime. These linings are fairly durable so long as they are kept free from moisture, but if left in a damp place the lime slacks and cracks Off. With a lining two tenths Of a millimeter in thickness I have made seventeen melts, each time chilling in an ice-bath, and at the end Of this time the lining was almost intact.
These linings are made from a mixture Of finely powdered quick lime and calcium nitrate, about four parts by weight Of the lime to one by weight of the nitrate. Care must be taken that the powders are thoroughly mixed. Such a mixture fuses to solid lime when sufficient heat is applied to drive Off all the nitric acid.
This last fact is not new. It is Often made use Of in the chemical department of Harvard University for preparing small boat-shaped crucibles suitable for melting small portions of metal. But one meets with considerable difficulty in keeping the powder in place on the steep sides of the crucible while it is being fused.
The method finally employed is to use a cylindrical-shaped crucible. This is clamped, Open end outward, in the chuck of a high-speed lathe and then set spinning. The mixed powder is then carefully blown inside the crucible where the centrifugal force holds it firmly on the sides in the form Of an even coating. The spinning crucible is then heated with a blast lamp until all the acid is driven Off. It is then removed from the lathe, set in an upright position, and the bottom sprinkled with a coating of the powder. This is finally fused on, the force of gravity keeping the powder in place.
About the Publisher
Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com
This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.
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- VerlagForgotten Books
- Erscheinungsdatum2019
- ISBN 10 0265761409
- ISBN 13 9780265761403
- EinbandTapa dura
- Anzahl der Seiten1052
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