Cold Sintering of Iron Powdered Metal Compacts and Their Performance

Abstract

Iron powder metallurgy is a well-established field in the powder metal (PM) industry due to its ease of processing and appreciable mechanical properties. One area that can contribute significantly to increased production and warrants more study is green machining. Additionally, our current global environmental state calls for more energy efficient processing methods. Cold sintering process (CSP) of metals may provide a means for decreasing required sintering temperature for metal via liquid phase sintering. Our application of CSP utilizes surface modification of iron particles to form an ultrathin hydrated phosphate layer (~10 nm). The hydrated layer promotes driving force for rearrangement and densification under warm compaction to yield compacts with significantly increased green strength up to 70 MPa. This method is currently under investigation for the impact of alloyed iron as well. Implementation of CSP for iron may result in increased mechanical properties, decreased sintering temperature requirements, and decreased energy consumption.