- 學位論文
Fe-Si-B-Cr-C非晶磁性粉末的絕緣披覆之研究
Investigation of insulation coating of Fe-Si-B-Cr-C amorphous magnetic powder
摘要
本文以旋淬水霧法(SWAP)製備之Fe-Si-B-Cr-C非晶粉末為研究對象，採用硝酸鈍化處理獲得絕緣軟磁粉末，並將粉末與高溫矽樹脂混合造粒，在室溫下使用1.31 GPa(密度為5.15 g/cm3)壓力壓製成環形磁粉芯，以分析其頻率特性與軟磁性質。藉由X光繞射儀(XRD)及掃描式電子顯微鏡(SEM)觀察粉末的微觀結構與表面形貌。以阻抗分析儀(LCR meter)和振動樣品磁力儀(VSM)量測樣品之頻率特性與軟磁性質。實驗結果顯示，經由8 vol.%硝酸絕緣處理之非晶磁性粉末在高頻(1 MHz)下具有優異的頻率特性和品質因子。在頻率特性上初始導磁率(?i)為29.03與品質因子(Q)為68.2，飽和磁化強度(Ms)為0.93 T與矯頑磁力(Hc)為89.6 A/m。此外，採用粉末冶金製程混合非晶粉末與合金粉末，並壓製成環形磁粉芯。在含有10 wt.%合金粉樣品中退火溫度為773 K持溫10分鐘之最大導磁率增加了69.8%。退火目的為改善軟磁性質和消除殘留應力。該混合粉末還具備有優異的軟磁性質，其飽和磁化強度(Ms)可由0.93 T增加至0.97 T，矯頑磁力(Hc)則由89.6 A/m降低至68.8 A/m。
並列摘要
The insulated soft magnetic powders were prepared by HNO3 passivation process with SWAP Fe-Si-B-Cr-C amorphous powder in this paper. The toroid-shaped cores were fabricated by pressing the mixture of the insulated magnetic powder and silicone resin under the pressure of 1.31 GPa (Density=5.15 g/cm3). Frequency characteristics and soft magnetic properties of the cores had been studied. XRD and SEM were utilized to observe microstructures and surface morphology of the powder. The frequency characteristics and soft magnetic properties of the samples were measured by LCR meter and VSM. The results show that amorphous magnetic powder by 8 vol.% nitric acid insulating process had good frequency characteristics and high quality factor in higher frequency (1 MHz). The value of initial permeability (?i) is 29.03, and the value of quality factor (Q) is 68.2. The value of saturation magnetization (Ms) is 0.93 T and coercive force (Hc) is 89.6 A/m. Furthermore, the amorphous powder are mixed with the Fe-Si-Cr alloy powder by the powder metallurgy process, and made into toroid-shaped cores. The maximum permeability of the toroid-shaped cores with 10 wt.% alloy powder sample annealed for 10 minutes at 773 K increases by about 69.8%. The cores are annealed to improve soft magnetic properties and decrease the stress. Besides, this mixing powders also indicated excellent soft magnetic properties such as the Ms is increased from 0.93 T to 0.97 T, and the Hc is decreased from 89.6 A/m to 68.6 A/m.