2022 Volume 63 Issue 3 Pages 329-334
Iron-based powder mixtures for the powder metallurgy process commonly contain solid lubricants. Both zinc stearate (ZnSt) and N,N′-ethylenebis(stearamide) (EBS), which are conventional lubricants in this field, exhibit similarly adequate lubrication performance. However, their effects on powder mixture flowability are different; that is, powder mixtures containing ZnSt exhibit better flowability than ones containing EBS. In this study, the adhesive and frictional properties of five surface combinations (iron–iron, iron–EBS, iron–ZnSt, EBS–EBS, and ZnSt–ZnSt) were investigated using surface force and resonance shear measurements. The adhesive forces obtained for all combinations were almost the same. On the other hand, the frictional forces for the iron–EBS and EBS–EBS combinations obtained from resonance shear measurement were larger than the others under low applied loads (<ca. 1.0 mN). This result suggests that the frictional properties of lubricants under low applied loads determine the powder mixture flowability.
This Paper was Originally Published in Japanese in J. Jpn. Soc. Powder Metallurgy 66 (2019) 554–559.
