DENSIFICATION OF LMH-2
Abstract
Ultra-high pressure hydrostatic equipment was obtained for use in BeH2 crystallization studies. During its installation the crystallization of high-purity Li-doped BeH2 (96 wt % BeH2, 1.3 wt % Li) was investigated using an improved design piston-mold apparatus. The high purity feed material tended to give a product with relatively high concentrations of crystalline Phase 338-208 and densities in the range 0.75-0.77 g/cc. As the pressure and temperature was increased, Phase 378-295 formed preferentially, as expected. Its density approached a value of 0.80-0.82 g/cc. Rate of temperature quench under pressure had no effect on extent of crystallization or polymorph distribution. On the other hand, a rapid pressure quench at elevated temperature is detrimental to the crystallization process. It was found that amorphous BeH2 can be prepared in a fused, glassy state by pre-compaction, then heating without pressure to 170-200C. Investigation of impurities in BeH2 showed that the presence of butoxide groups in the pyrolysis feed, di-t-butylberyllium etherate, enhanced the thermal stability of the t-butyl groups. This information aided the production of the highest purity Li-doped BeH2 obtained to date. Attempts to improve purity even further by hydrogenolysis of residual alkyl groups proved unsuccessful.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1966
- Accession Number
- AD0379195
Entities
People
- E. M. Marlett
- G. J. Brendel