Hot Isostatically Pressed Sm(2)(TM)17 Magnets.
Final rept. 14 Feb 83-13 Feb 85,
CHARLES STARK DRAPER LAB INC CAMBRIDGE MA
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High energy product TDK-type, 2-17,Sm Cu, Fe, Zr, Co z magnets were produced successfully using hot isostatic pressing HIP. The best combination of properties was obtained in magnets containing about 26.5 wt Samarium, 4 wtCopper, 20 wtIron, 2 wtZirconium, and 0.4 wtOxygen, and balance cobalt. The maximum value of BH max measured was 24.8 MGOe for a magnet with B sub R 10.7 kG and H sub ci 15.5 kOe. With higher levels of Cu up to 8 wt much higher H sub ci values up to 28.5 k0e were measured. A minimum amount of Zr was found to be essential to H sub ci development. HIPing was successfully performed at 1100 C. This resulted in near-complete densification with little grain growth. Post-HIP homogenization was found to lead to enhanced properties after solution treatment and aging. 825 C was determined as the optimum peak aging temperature. Magnets produced from coarse 15 min grind time alloy powders with low oxygen contamination had the properties indicated above. These were substantially superior to magnets produced from conventionally made much finer 1 hour grind time sinter grade powder, which contained a higher level of oxygen and showed lower H sub ci even after excess Sm was added to compensate for the higher oxygen. However, H sub ci values of up to 8 kOe were found to develop in magnets made from fine 1 hour grind time powders which were processed for lower oxygen contamination in a glove box.
- Electrical and Electronic Equipment
- Metallurgy and Metallography