CN110845228B - 一种贫铁软磁铁氧体、电磁波吸收材料及其制备方法 - Google Patents

一种贫铁软磁铁氧体、电磁波吸收材料及其制备方法 Download PDF

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CN110845228B
CN110845228B CN201911116469.0A CN201911116469A CN110845228B CN 110845228 B CN110845228 B CN 110845228B CN 201911116469 A CN201911116469 A CN 201911116469A CN 110845228 B CN110845228 B CN 110845228B
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颜冲
张建明
王育伟
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Abstract

本发明涉及一种贫铁软磁铁氧体、电磁波吸收材料及其制备方法，它由主成分和副成分组成，以摩尔百分比计，所述主成分包括46.0~49.9mol%的Fe2O3、21.0~26.0mol%的ZnO以及余量的MnO；以主成分质量和为基准，所述副成分至少含有500~2500ppm的TiO2或1000‑5000ppm的SnO2。通过采用特定组分的主成分和副成分进行复配，这样能够使得其做成的电磁波吸收材料在30MHz和500MHz频率的反射损耗都在20dB以上。

Description

一种贫铁软磁铁氧体、电磁波吸收材料及其制备方法
技术领域
本发明属于磁性材料领域，涉及一种软磁铁氧体，特别是涉及一种贫铁软磁铁氧体、电磁波吸收材料及其制备方法。
背景技术
随着5G通讯等电子信息技术的不断发展，人们对能够吸收电磁波的吸收材料需求越来越大。电磁波吸收材料的吸收性能可用以下公式计算得到的反射损耗（Ref(dB)）来评价：
Figure 246868DEST_PATH_IMAGE001
（1）；
Figure 101692DEST_PATH_IMAGE002
（2）；
上式中
Figure 819112DEST_PATH_IMAGE003
为波长（=c/f），复数磁导率为
Figure 417584DEST_PATH_IMAGE004
，复数介电常数为
Figure 169639DEST_PATH_IMAGE005
-
Figure 257681DEST_PATH_IMAGE006
，d为吸收磁片的厚度。一般而言，在一个给定的频段下反射损耗大于20dB及以上的吸波材料具有优良的吸波性能；通过降低吸收磁片的厚度可以节约成本。所以在保持给定频段下反射损耗的前提下，吸收磁片优选相对较薄的厚度。
MnZn铁氧体和NiZn铁氧体烧结材料都可以作为这类吸波材料使用。NiZn铁氧体材料因为含有价格昂贵的Ni元素，推高了材料的制造成本。由MnZn铁氧体制成电磁波吸收片与由NiZn铁氧体制成的相比而言价格便宜，即使在吸收片厚度较薄时也能够发挥出优良的吸收性能。但MnZn铁氧体制成的电磁波吸收片通常只用于30MHz以下的低频带，所以需要开发出一种即使在30MHz频率以上、特别是30MHz~500MHz频率范围都能够实现优良吸波性能的MnZn铁氧体吸波材料。
发明内容
本发明目的是为了克服现有技术的不足而提供一种贫铁软磁铁氧体。
为达到上述目的，本发明采用的技术方案是：一种贫铁软磁铁氧体，它由主成分和副成分组成，以摩尔百分比计，所述主成分包括46.0~49.9mol%的Fe2O3、21.0~26.0mol%的ZnO以及余量的MnO；以主成分质量和为基准，所述副成分至少含有500~2500ppm的TiO2或1000-5000ppm的SnO2。
优化地，所述副成分还包括50~200ppm的Na2O。
优化地，所述副成分还包括50~300ppm的Ta2O5。
本发明的又一目的在于提供一种电磁波吸收材料，它由上述贫铁软磁铁氧体构成。该电磁波吸收材料可以为常规的片状等，其厚度≤6.5mm。
本发明的再一目的在于提供一种电磁波吸收材料的制备方法，它包括以下步骤：（a）按比例称取所述主成分和所述副成分，混合后于850~950℃进行预烧得预烧料；（b）将所述预烧料进行砂磨、干燥，添加粘接剂进行造粒、成型、烧结得烧结体；（c）将所述烧结体于1250~1350℃进行保温烧结即可。步骤（b）中，所述粘接剂为聚乙烯醇，其添加量为所述预烧料的1wt%。步骤（b）中，所述预烧的温度为900℃、时间为2h；步骤（c）中，所述烧结的温度为1300℃、时间为5h。
由于上述技术方案运用，本发明与现有技术相比具有下列优点：本发明贫铁软磁铁氧体，通过采用特定组分和含量的主成分和副成分进行复配，这样能够使得其做成的电磁波吸收材料在30MHz和500MHz频率的反射损耗都在20dB以上。
具体实施方式
本发明贫铁软磁铁氧体，它由主成分和副成分组成，以摩尔百分比计，所述主成分包括46.0~49.9mol%的Fe2O3、21.0~26.0mol%的ZnO以及余量的MnO；以主成分质量和为基准，所述副成分至少含有500~2500ppm的TiO2或1000-5000ppm的SnO2。通过采用特定组分和含量的主成分和副成分进行复配，这样能够使得其做成的电磁波吸收材料产生复合效应而在30MHz和500MHz频率的反射损耗都在20dB以上。所述副成分还包括50~200ppm的Na2O，这样容易形成玻璃相存在于晶界，有利于烧结密度的提高；所述副成分还包括50~300ppm的Ta2O5，这样可以细化晶粒，促进晶粒生长均匀化。上述副成分还可能包含其它特别加入或不可避免的杂质，一般相对于主成分质量和为几个ppm至几百ppm，如SiO2、CaO、NiO、MgO、Al2O3、Cr2O3、P2O5、B2O3、SO3、CuO等一种或多种；它们对最终电磁波吸收材料的影响不大。
本发明电磁波吸收材料，它由上述贫铁软磁铁氧体构成。该电磁波吸收材料可以为常规的片状等，其厚度可以根据实际需要选择，如≤10mm，进一步地可以选择为≤6.5mm。上述电磁波吸收材料的制备方法，它包括以下步骤：（a）按比例称取所述主成分和所述副成分，混合后于850~950℃进行预烧得预烧料；（b）将所述预烧料进行砂磨、干燥，添加粘接剂进行造粒、成型、烧结得烧结体；（c）将所述烧结体于1250~1350℃进行保温烧结即可。步骤（b）中，所述粘接剂为聚乙烯醇，其添加量为所述预烧料的1wt%。步骤（b）中，所述预烧的温度为900℃、时间为2h；步骤（c）中，所述烧结的温度为1300℃、时间为5h（上述烧结温度范围对产品的性能影响不大）。
下面将结合对本发明优选实施方案进行详细说明：
实施例1-11、对比例1-3
实施例1-11、对比例1-3分别提供一种电磁波吸收材料，具体制备步骤如下：
（a）准备作为主成分的Fe2O3、MnO和ZnO，准备作为副成分的TiO2、SnO2、Na2O（以Na2CO3形式）和Ta2O5；按表1称取主成分和副成分在砂磨机中进行湿式混合0.5小时，干燥后在空气中900℃下预烧2小时得到预烧料；
（b）将预烧料在砂磨机中砂磨2小时，干燥后（相对于干燥后的预烧料，100wt%）添加1.0wt%的聚乙烯醇（市售）作为粘接剂进行造粒、成型、烧结，最终得到外径为7.0mm、内径为3.0mm、高为10.0mm的圆环形烧结体；
（c）将烧结体在1300℃下进行烧结，保温时间为5小时。
上述各例产品使用网络分析仪在25℃下测量磁环样品的反射损耗（Ref（dB））：测量时样品插入到同轴管中（在30MHz~500MHz的频率范围，Ref（dB）在20.0dB以上为良好）。
表1实施例1-11、对比例1-3电磁波吸收材料的性能测试表
Figure 462397DEST_PATH_IMAGE007
如表1所示，在贫铁软磁铁氧体中当主成分以及副成分的含量在本发明的范围内（实施例1-11），在30MHz-500MHz的频率范围的Ref（dB）都在20.0dB以上；而当贫铁软磁铁氧体中主成分或副成分的含量在本发明的范围之外（比较例1-3）时，在30MHz-500MHz频率范围的Ref（dB）均产生劣化。
上述实施例只为说明本发明的技术构思及特点，其目的在于让熟悉此项技术的人士能够了解本发明的内容并据以实施，并不能以此限制本发明的保护范围，凡根据本发明精神实质所作的等效变化或修饰，都应涵盖在本发明的保护范围之内。

Claims (1)

1.一种电磁波吸收材料，它由贫铁软磁铁氧体构成，所述贫铁软磁铁氧体由主成分和副成分组成，其特征在于：以摩尔百分比计，所述主成分包括47.0mol%的Fe2O3、24.0mol%的ZnO以及29.0 mol%MnO；以主成分质量和为基准，所述副成分含有1000ppm TiO2、100ppmNa2O和200ppm Ta2O5；
所述电磁波吸收材料的制备步骤如下：
（a）准备作为主成分的Fe2O3、MnO和ZnO，准备作为副成分的TiO2、Na2O和Ta2O5；称取主成分和副成分在砂磨机中进行湿式混合0.5小时，干燥后在空气中900℃下预烧2小时得到预烧料；所述Na2O以Na2CO3形式存在；
（b）将预烧料在砂磨机中砂磨2小时，干燥后添加聚乙烯醇作为粘接剂进行造粒、成型、烧结，最终得到外径为7.0mm、内径为3.0mm、高为10.0mm的圆环形烧结体；所述聚乙烯醇的添加量为所述预烧料质量的1.0%；
（c）将烧结体在1300℃下进行烧结，保温时间为5小时。
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