摘要
为了获得轻质、低频、高效吸波剂,采用自反应淬熄法,分别以Fe+Si+Al、Fe+Si+Al+KNO_3为反应体系制备了FeSiAl软磁合金空心微珠,通过SEM、XRD、矢网分析仪等手段研究了KNO_3对其密度、形貌、相组成和低频吸波性能的影响。结果表明,未加KNO_3时,反应难以进行,淬熄产物由球形颗粒、类球形颗粒、不规则颗粒和片状颗粒组成,物相主要为Fe、Si、Al及部分Fe_(0.9)Si_(0.1),未生成FeSiAl合金,基本无吸波性能;添加KNO_3后,反应体系的淬熄产物主要为空心微珠,粒径分布均匀,物相由Fe_3Si_(0.5)Al_(0.5)、Fe_3Si_(0.7)Al_(0.3)、Fe_(0.9)Si_(0.1)和Fe组成,获得了FeSiAl合金,在5 mm吸波剂厚度条件下,吸波试样最低反射率达–22.1 dB,吸收峰值对应频率为7.0 GHz,低于–10 dB的有效吸收频带为5.1~8.4 GHz,带宽达3.3 GHz。KNO_3分解反应所产生的高放热量和大量气体是促使反应温度升高、反应产物熔融、目标产物形成、成球率和空心率提高及低频吸波性能显著改善的根本原因。和机械合金化法制备的片状FeSiAl软磁合金相比,自反应淬熄法制备的FeSiAl空心微珠的低频吸波频带有效拓宽,同时材料的密度降低了38%,有效实现了新型低频吸波材料"薄、宽、轻、强"的特点。
In order to obtain absorbents with light weight,low frequency and high efficiency,FeSiAl magnetically soft alloy hollow microspheres were prepared by self-reactive quenching technique based on Fe＋Si＋Al and Fe＋Si＋Al＋KNO3 reactive systems.Effect of KNO3 on their density,morphology,phase and microwave absorption properties in the low frequency band was studied by SEM,XRD and vector network analyzer.The results show that chemical reactions cannot happen without KNO3.In addition,the quenched products consist of spherical particles,near-spherical particles,irregular particles and lamellar particles.The phase components are Fe,Si,Al and Fe0.9Si0.1.FeSiAl alloys are not formed and thus hardly any microwave absorption properties occur.After adding KNO3,the quenched products consist mainly of hollow microspheres with uniform particle size distribution.The phases are composed of Fe3Si0.5Al0.5,Fe3Si0.7Al0.3,Fe0.9Si0.1 and Fe.FeSiAl alloys are obtained.The minimum reflectivity of the absorbent sample at 5 mm thickness is–22.1dB,and the corresponding frequency is 7.0 GHz.The effective absorption frequency band below–10 dB is 5.1-8.4 GHz,with a bandwidth of 3.3 GHz.The high heat-releasing and large amounts of gas from the decomposition of KNO3 increase the reaction temperature.In addition,the target products are obtained and then melted.Moreover,both the spherical rate and the hollow rate improve.These are the reasons for the obvious improvement in microwave absorption properties at low frequency.Compared with the flake FeSiAl magnetically soft alloy prepared by mechanical alloying method,the FeSiAl hollow microspheres prepared by the self-reactive quenching technique have a broader absorption frequency band at low frequency and a density reduction of 38%.So the new absorbent effectively achieves the characteristics of＂thin,broad,light and strong＂at low frequency.
作者
王建江
蔡旭东
温晋华
许宝才
Wang Jianjiang1, Cai Xudong2, Wen Jinhua1, Xu Baocai1(1. Engineering University of the Army, Shijiazhuang 050003, China;2. 63983 Troops, Wuxi 214035, China)
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2018年第10期3072-3079,共8页
Rare Metal Materials and Engineering
基金
国家自然科学基金(51172282)
河北省自然科学基金(E2015506011)
武器装备预研基金(9140A12040211JB34)
关键词
KNO3
软磁合金
FeSiAl
空心微珠
低频吸波
自反应淬熄法
KNO3
magnetically soft alloy
FeSiAI
hollow microsphere
microwave absorption at low frequency
self-reactive quenchingtechnique
