PROCESSING SINTERED ALNICO
Processing begins with the controlled blending of fine metal powders consisting primarily of aluminum, nickel, cobalt and iron.
A wax lubricant is added at this stage to aid the subsequent pressing process.
The mixed powder is then compacted to form the required shape using varied press technology. Close dimensional control is maintained by statistical process control (SPC), both at this stage and after sintering.
De-waxing through a low temperature furnace removes the pressing lubricant prior to sintering.
Sintering is undertaken at high temperature under a protective atmosphere of hydrogen. An homogeneous fully dense alloy results.
Further heat treatment is required for most alloys to introduce improved magnetic properties. Anisotropic properties can be induced by additional specialized heat treatment. For those materials that have been heat treated, the final part of the process is multi-stage tempering which reduces brittleness but more importantly, further enhances the magnetic performance and stabilizes the material.
To achieve very high dimensional control specific surfaces can be machined to very close tolerances using high volume grinding machines.
Final inspection before dispatch or subsequent assembly, ensures that all parts conform both physically and magnetically to specification.