文章信息/Info

Title:

High Frequency Electromagnetic Properties of FeCoSi Magnetic Powders via Phosphorization

文章編號:

1674-3962(2021)03-0161-06

作者:

陳起明; 周晨暉; 嚴　密; 吳　琛

（浙江大學材料科學與工程學院 硅材料國家重點實驗室，浙江 杭州 310027）

Author(s):

CHEN Qiming;  ZHOU Chenhui;  YAN Mi;  WU Chen

(State Key Laboratory of Silicone Materials,School of Materials Science and Engineering, Zhejiang University, Zhejiang 310027, China)

關鍵詞:

FeCoSi合金;  磷化處理; 電磁參數; 高頻性能; 吸波機制

Keywords:

FeCoSi alloy;  phosphorization; electromagnetic parameters;  high-frequency properties;  absorbing mechanism

分類號:

TM25

DOI:

10.7502/j.issn.1674-3962.202012024

文獻標志碼:

A

摘要:

采用快淬甩帶和高能球磨工藝制備了成分為Fe70Co12Si18（合金名稱中數字為原子百分數）的片狀合金磁粉，并用磷酸酒精溶液對磁粉進行了磷化處理。重點研究了磷化前后及不同磷酸濃度對FeCoSi磁粉電磁參數和微波吸收性能的影響。結果表明，隨著磷酸濃度的提高，FeCoSi合金吸波材料的介電常數實部和虛部均減小, 磁導率實部基本不變、虛部有少量減小，反射損耗（RL）增加。20%（質量分數）磷酸磷化樣品在厚度為1.6 mm時的RL為-33.4 dB，帶寬為5.2 GHz。高能球磨增加了磁粉的形狀各向異性，使樣品具有了較高的自然共振頻率，且自然共振頻率隨著磷酸濃度的升高而進一步提高。樣品經磷化處理后在表面生成了磷酸鹽層，該磷酸鹽層不僅通過增大材料的電阻率調控了樣品的介電常數，有效改善了樣品的阻抗匹配，同時向樣品中引入了磁粉/磷化層等界面，增強了樣品的界面極化作用。

Abstract:

Flaky Fe70Co12Si18 (atomic percentage) magnetic powders were prepared by quenching fastly combined with melt-spinning and high energy ball milling, followed by phosphorization with phosphoric acid alcohol solution. Effects of the concentration of the phosphoric acid solution on both the electromagnetic parameters and the microwave absorption performance of the FeCoSi powders was disclosed. With increased phosphoric acid concentration, both the real and imaginary parts of the permittivity decreased, while the real part of the permeability experienced subtle change with slight decrement for the imaginary part of the permeability. What’s more, enhanced reflection loss (RL) has been achieved with increased phosphoric acid concentration. The sample after 20%（mass fraction） phosporization exhibited optimal absorption with a minimum RL of -33.4 dB and a broad effective bandwidth of 5.2 GHz at a small thickness of 1.6 mm. The magnetic powder exhibited large natural resonance frequency due to the enhanced shape anisotropy after ball milling. The natural resonance frequency further improved with increased phosphoric acid concentration. The phosphate coatings fabricated on the surface of the powders after phosphorization not only effectively improved the impedance matching by increasing the resistivity and adjusting the permittivity of the material, but also enhanced the interface polarization by introducing interfaces between the powers and the phosphate layers.