Apr 20th, 1:00 PM - 3:00 PM
Magnetic-Field Liquid-Phase Sintering
Dr. Peter Müllner
Processing magnetic materials to tailor microstructures with specific crystallographic textures can be accomplished using the magnetic field liquid phase sintering method (MFLPS), which is currently being developed at Boise State University. This process allows us to align the individual grains and modify the magnetic, mechanical, and other properties of the material. The MFLPS method is achieved by applying a magnetic field to a pressed pellet of two materials, one with a high melting point and one with a low melting point, during a two-step heat treatment. During the first heating step below the Curie temperature, the applied magnetic field creates a torque on the high-melting ferromagnetic component that aligns the grains of the magnetic phase while the second component is in its liquid phase. The sintering then occurs during the second heating step at higher temperature without magnetic field. For this research steel shot and gallium were compacted together to create a composite pellet. This was done in a series of compositions, until we found a suitable ratio to hold the pellet together. This ratio is 70 weight percent steel shot and 30 weight percent gallium. We found at 60 weight percent steel shot and 40 weight percent gallium, there is an excess of gallium material that seeps out of the die during compression. Below 30 weight percent gallium, the pellet did not retain its desired shape. Similar experiments will be performed with cobalt-gallium, steel shot-aluminum, and cobalt-aluminum systems.