利用高生坯强度润滑剂开发无线通讯装置用PM软磁零件

Developing a Soft Magnetic PM Component Used in Wireless Communication Devices with High Green Strength Lubricants

软磁烧结铁框是无线通讯装置中的一个重要零件 ,用其来防止电子元件间的电磁干扰和对人有害的电磁辐射。铁框结构复杂且轻巧 ,依据电子电路的具体设计 ,壁厚可薄至 0 8mm。传统的金属冲压成形因零件挠曲而不能满足尺寸公差与平直度的要求。用粉末冶金工艺制造铁框面临的难题是因壁薄 ,截面处易碎而使生坯难以搬运。用常规的硬脂酸锌或EBS蜡之类润滑剂混粉 ,生坯的废品率高达 5 0 %。因此 ,采取了用新近开发的高生坯强度润滑剂 ,制造烧结铁框的方法。为使开发的烧结铁框能达到磁性要求 ,选用了添加 0 45 %磷的高纯铁粉ATOMET 10 0 1HP。采用冷压、温压及在压制后进行和不进行固化的不同工艺 ,测试了几种高生坯强度润滑剂系列 ,从中选出了一种使压坯强度满足粉末冶金铁框压坯搬运要求的润滑剂系列 。

A soft iron frame is an essential component of electronic circuits used in wireless communication devices to prevent the electromagnetic interference between electronic elements and the electromagnetic radiation which is harmful to the human. The structure of the iron frame could be complicated and delicate with walls as thin as 0.8 mm depending on the specific designs of electronic circuits. Traditional metal stamping process could not satisfy the requirements of the dimensional tolerance and the flatness because of the part distortion. A challenge was faced with manufacturing the iron frame using the PM process was the green compact handling due to its fragileness at thin wall sections. The scrap rate of green compacts was as high as 50% with the powder mix using the regular lubricants such as zinc stearate or EBS wax. The approach for manufacturing the PM frame by using the recently developed high green strength lubricants was taken. A high purity iron powder ATOMET 1001HP with the addition of 0.45% phosphorus was selected for the development of the frame to meet the requirements of magnetic properties. Several high green strength lubricant systems were evaluated with cold and warm compacting processes, also with or without post-compaction curing. A specific lubricant system was chosen for the frame, which yielded a sufficient green strength for compact handling and minimized the production cost.