Fracture Initiation in Irdome Grade MgF2.
NAVAL RESEARCH LAB WASHINGTON D C
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Analysis of Irdome grade MgF2 specimens from one of the leading MgF2 manufacturers showed that 50-75 often failed from foreign particles or occasionally large grains. The foreign particles were almost exclusively SiO2, which appears to be introduced by abrasion from the Si02 crucibles used for processing the SiO2 powder. Elimination of these particles would be relatively easy, but is not expected to significantly raise strengths because machining flaws, which are the other predominant source of failure limits strengths to similar levels as the SiO2 particles do. Practical limitation on reducing the sizes of machining flaws indicate that if significantly improved mechanical performance of Irdomes is required, it is not likely to be obtained by improving MgF2. Development of new materials is thus required to provide higher performance. Author
- Ceramics, Refractories and Glass
- Infrared Detection and Detectors