Anisotropy of Sintering Shrinkage of Sr-Ferrite Compacted under Magnetic Field and Its Application to Sinter Joining.

For the purpose of producing ferrite part with a complicated shape which has different alignment of the ferrite crystallites, the feasibility of combined sinter joining method was studied. Disk was compacted under magnetic field of 915kA⋅m-1 and ring compacted under non-magnetic field, respectively. The two compacts was assembled into a unit and then sintered at 1150°C.The oriented ferrite compacted under the magnetic field has dimensional anisotropy owing to sintering shrinkage. The anisotropic shrinkage, which will be capable of affecting the joining behavior, was investigated with respect to the effects of powder particle size, powder lubricant, compacting lubricant and compacting pressure before applying the magnetic field. It was found that the sintering shrinkage and degree of ferrite alignment in forming using a dry-type lubricant are largely affected by the compacting pressure before applying the magnetic field, even if the compacting pressure was several MPa or so, and that the alignment of the anisotropic compacts were similar to that of the compact consolidated under non-magnetic field. Effect of the magnetic field on joint strength of the sinter joined compact was also investigated.