Materials Research for Advanced Inertial Instrumentation. Task 3: Rare Earth Magnetic Material Technology as Related to Gyro Torquers and Motors.
Abstract
Flux stability experiments on SmCo5 have demonstrated that no clear correlation or dependence exists between the stability of flux in a magnet and its intrinsic properties Hk and Hci, a belief that has gained wide acceptance on the basis of earlier reported findings. This study shows that the level of the measured flux decay rate is, in contrast, intimately related to the amount of the Sm2C07 phase present in the material (the higher the level) , the greater is the decay rate) as well as to the cooling procedure. Fast cooling suppresses precipitation of excess oxygen that is present is solid solution at elevated temperatures and this results in a high decay rate at lower operating temperatures. The present results are considered extremely significant in that these provide, it is believed, for the first time the recipe to produce SmC05 magnets which are very stable with time. The preferred fabrication procedure should include producing of magnets with a composition of near-stoichiometric SmCo5 with a low level of oxygen and possibly a low level of internal stress.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1982
- Accession Number
- ADA126982
Entities
People
- Debanik Das
- K. Kumar
Organizations
- Charles Stark Draper Laboratory