铁粉表面硫化处理制备高密度Fe-Cu-C合金

突破常规铁基粉末合金的制备工艺,设计出一种制备高密度Fe-Cu-C合金的新工艺.通过对铁粉表面进行硫化处理,Fe与S反应合成FeS,均匀包覆在Fe粉颗粒表面,形成一层FeS润滑薄膜,有利于降低压制摩擦力.通过X射线衍射、扫描电镜、和场发射扫描电镜分析研究材料的物相、元素分布和显微组织.研究结果表明:包覆在铁粉颗粒表面的FeS薄膜,有利于提高压坯密度,活化烧结.当S质量分数为0.5%时,硫化处理的Fe-2Cu-0.8C合金的力学性能优异,压坯密度7.31 g·cm-3,硬度78.6 HRB,抗拉强度485 MPa;当S质量分数达到0.8%时,多余的FeS占压制体积分数,导致试样的压坯密度降低,力学性能降低.

Sulfurizing treatments on the surface of iron powder for preparing high density Fe-Cu-C alloys

Breaking through the conventional P/M processing, a new process for preparing high density Fe-Cu-C alloys was de-signed. Through sulfuring treatments on the surface of iron powder, Fe reacts with moderate S to generate FeS, which is uniformly coa-ted on the surface of iron powder particles and formed a thin-layered FeS lubrication film. The FeS lubrication film is useful for reduc-ing the friction of compaction. The phase, element distribution and microstructure were characterized by X-ray diffraction, scanning electron microscopy and field emission scanning electron microscopy. The results show that the FeS lubrication film coating on the sur-face of iron powder is significant to improve the green density and activate sintering. After sulfuring treatments, Fe-2Cu-0. 8C alloys with 0. 5% S exhibit higher mechanical properties:the green density reaches 7. 31 g·cm-3 , the hardness 78. 6 HRB, and the tensile strength 485 MPa. When the mass fraction of S is 0. 8%, redundant FeS accounts for pressing volume fraction, resulting in the decrea-sing of green density and mechanical properties.