Research on Iron Powder Purity and Processing Conditions for Soft Magnetic Composites
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摘要: 为生产高性能的电机铁芯,软磁复合材料(Soft Magnetic Composite,SMC)通常以高纯高压缩性铁粉为原料,如果能用较低纯度铁粉取代高纯铁粉,将使生产成本大大降低。本文以3种不同纯度铁粉为原材料,通过在不同工艺条件下压坯密度及表面显微硬度的变化,来表征铁粉纯度对压坯密实程度及加工硬化程度的影响。结果表明:铁粉纯度、杂质元素种类及含量、铁粉颗粒形貌均影响粉末压坯密度。较低纯度铁粉的压坯在500℃氮气中退火30 min,硬度迅速降低30%;而相同条件下高纯铁粉的压坯表面硬度基本不变。当热处理温度达到再结晶温度时,再结晶过程可使硬度降低近50%。Abstract: High purity and high compressibility iron powder is commonly used in soft magnetic composite(SMC)materials for producing high performance motor cores.If it can be substituted by some less pure iron powders,the cost for SMC production would be decreased greatly.In order to characterize the effects of iron powder purity on the extents of compaction and work hardening,three iron powders of different purities are utilized to analyze the changes in green density and surface microhardness under different processing conditions.Resultsindicate that many characteristics of iron powder,such as purity,type and content of impurities and iron particle morphology influence the green density of compacts.After annealing in nitrogen at 500℃ with the holding time of 30min,the hardness of the less pure powders decrease by about 30%,while that of high purity powder under the same condition is unconspicuous.When heating up to the recrystallization temperature,the recrystallization process of iron grains results in the reduction of the microhardness by less than 50%.
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Keywords:
- Iron powder /
- SMC /
- Compacts /
- Compaction /
- Heat treatment
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