Sintering of die-pressed Co5Sm magnets

An experimental program was carried out to establish the conditions necessary to achieve successful sintering of Co5Sm powder. The objective was to sinter the as-pressed powder to the highest possible density without having the powder suffer a loss of coercive force. It was found that to maintain coercive force it was necessary to have an oxygen scavenging agent intimately dispersed throughout the powder. This was accomplished by adding either samarium metal or samarium hydride powder to nominally stoichiometric Co5Sm to give an average composition in the range of 36–37.5 wt% Sm. In addition it was found that highest sintered densities were achieved with a total samarium content slightly greater than that needed to maintain a high coercive force in the densified compacts.