Manufacturing Methods for Samarium Cobalt Magnets.

摘要

Processes and techniques were established for the pilot line manufacturing of samarium-cobalt permanent magnets for use in high performance periodic permanent magnet focused traveling-wave tube amplifiers. The objective of achieving a capacity for 1000magnets per month was exceeded. Typical properties of magnets produced in quantity are: energy product (BH max of 13 - 15 x 1,000,000 GOe, B sub r of 7800plus or minus 200gauss,and Hc of 6800plus or minus 300Oe. Extensive measurements were made to establish temperature characteristics of second quadrant properties,long term stability,and maximum temperature use in an operating device. Irreversible temperature coefficients for magnetic properties up to 255C were found to depend linearly on demagnetizing field,whereas reversible temperature coefficients varied only slightly. Magnet rings assembled in a PPM stack (high demagnetizing factor) exhibited < 4% measurable change in peak axial field at 225C for over 900hours. Device evaluation of magnets clearly established the superior performance possible with samarium-cobalt. Higher power and the attendant higher temperature are now achievable with TWT's. (Author)