模具润滑温压成形法制作的高密度铁基烧结体的磁性与组织

Magnetic properties and microstructure of high density sintered iron by warm compaction using die wall lubrication

烧结铁是一种好的软磁材料,但其磁通密度比铸造材料的低。低的磁通密度是由于密度低所引起的。本研究开发了一种温压与硬脂酸锂模壁润滑技术(WC-DWL)。使用该技术,得到了密度非常高的成形体。纯铁粉在1176MPa的压力下成形,经1523K烧结后的性能如下:密度=7.76Mg/m3,μm=5300,B160=1.16T,B240=1.28T,B400=1.40T,B2k=1.60T,bHc=110A/m。一些烧结铁表现出各向异性的变化与组织,这导致异常晶粒长大到长度为数毫米。这种异常长大在试样成形密度较高时更为明显。

Sintered iron was one of good soft magnetic materials. However, its magnetic flux density was smaller than those of wrought magnetic iron. The small magnetic flux density was caused by low sintered density. In order to increase the sintered density, we developed a new warm compaction technique using die wall lubricatlon（WC- DWL） with lithium stearate. According to the method, very high-density of sintered body could be fabricated. Pure iron powder compacted at 1 176MPa and sintered at 1 523K had properties as follows;sintered density = 7.76Mg/m^3, μm= 5 300, B160 = 1.16T, B240 = 1.28T, B400=1.40T, B2k=1.60T, and bHc = 110A/m. Some of the sintered iron showed anisotropic dimensional change and anisometric , which were linked to abnormal grain growth up to several mm in length. This anomaly was the more pronounced the higher the green density of the specimens was.