Effect of warm compaction lubricant on the properties of Fe-based powder metallurgy materials

Abstract

Effects of composite lubricant, consisted of polyethylene wax, stearic acid amide and polyamide wax, and compaction temperature on the properties of Fe-based powder metallurgy materials were investigated through differential scanning calorimeter (DSC), scanning electron microscopy (SEM) and property tests. The results indicate that the glass transition temperature of composite lubricants increase with the content of polyamide wax, while the glass transition regions and the particle size of the composite lubricants are notably decreased. The flow rate and apparent density are 33–39 s/50 g and 3.196–3.257 g cm−3, respectively. The green density and green bending strength of the samples compacted at 120 °C initially increase and then decrease with the increase of the polyamide wax content in the composite lubricant, and the maximum green density and green strength of the A3 samples reach up to 7.11 g cm−3, 18.785 MPa, respectively, while the minimum ejection force of the samples is 3.6 kN. The reduced quantity and size of the pores together with the extensive powder particle interlocking present in the fracture morphology of the warm compact samples. Unlike controlled by pores of room temperature compaction sample, breakouts of warm compact samples become more controlled by the particle lubricant interfaces.