Spark Plasma Sintered Mn-Al (Magnets) Production and Characterization with Experimental Design

Abstract

Mn-Al alloys are important alloys due to their magnetic properties and have been identified as permanent magnets. This alloy possesses magnetic properties and can be manufactured at a relatively low cost. Mn-Al alloys could be an alternative to rare earth magnets and hard ferrites and have a promising future. In this study, the effects of sintering temperature, holding time and pressure on densification, average grain size and magnetic properties of the SPS-ed Mn-Al alloys were observed. However, with the different sintering parameters, the magnetic phase τ phase could be achieved. To obtain the τ phase, different annealing methods were tried, yet samples heated to 650°C and air cooled exhibited magnetic properties. This sample was selected from various sintering parameters due to its high density of 99% N6 (800°C – 300 sec – 60 MPa) and has an average grain size of 137±18.1 µm. The uniqueness of this work is that statistical approaches such as Taguchi design of experiment (DOE) and regression were used for optimization of the manufacturing process.