ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
The gas-solid-reaction (GSR) was used to introduce interstitial carbon atoms into Sm2Fe17−xGax compounds with x=0, 0.5, 1, and 2. For this process, powders made from homogenized ingots were annealed at 500 °C under methane for different times. The thermostability increases for small amounts of Ga and the investigation shows that Sm2Fe16.5Ga0.5Cy is stable up to 750 °C. In the case of Sm2Fe15Ga2Cy carburized for 6 h (y=2.0) and 18 h (y=2.2), the x-ray diffraction patterns show the Th2Zn17-type structure only. After annealing at 800 °C for 20 min the 6 h carburized sample shows a small amount of α-Fe and other phases and there is a large Fe content after annealing at 850 °C. For an 18 h carburized sample, less Fe and no other phases have be seen after annealing at 800 °C, i.e., the material is nearly single phase. The result that longer carburization times stabilize the Th2Zn17-type structure could also be manifested by Kerr microscopy. A comparison with mechanically alloyed Sm2Fe15Ga2C2 powders prepared with Sm excess shows that those are very stable up to 900 °C. The density of fine-grained Sm2Fe17−xGaxCy could be increased by hot pressing, but the degree of compaction and the phase purity very sensitively depend on the Ga content. © 1997 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.365542
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