Xiaolei Su
材料科学技术（英）
The SiC powders by Al or N doping have been synthesized by combustion synthesis, using Al powder and NH4Cl powder as the dopants and polytetrafluoroethylene as the chemical activator. Characterization by X-ray diffraction, Raman spectrometer, scanning electron microscopy and energy dispersive spectrometer demonstrates the formation of Al doped SiC, N doped SiC and the Al and N co-doped SiC solid solution powders, respectively. The electric permittivities of prepared powders have been determined in the frequency range of 8.2−12.4 GHz. It indicates that the electric permittivities of the prepared SiC powders have been improved by the pure Al or N doping and decrease by the Al and N co-doping. The paper presents a method to adjust dielectric property of SiC powders in the GHz range.
关键词:
Silicon carbide
Xiaolei Su
材料科学技术（英）
The SiC powders by Al or N doping have been synthesized by combustion synthesis, using Al powder and NH4Cl powder as the dopants and polytetrafluoroethylene as the chemical activator. Characterization by X-ray diffraction, Raman spectrometer, scanning electron microscopy and energy dispersive spectrometer demonstrates the formation of Al doped SiC, N doped SiC and the Al and N co-doped SiC solid solution powders, respectively. The electric permittivities of prepared powders have been determined in the frequency range of 8.2−12.4 GHz. It indicates that the electric permittivities of the prepared SiC powders have been improved by the pure Al or N doping and decrease by the Al and N co-doping. The paper presents a method to adjust dielectric property of SiC powders in the GHz range.
关键词:
Silicon carbide
欧秋仁
,
嵇培军
,
肖军
,
赵亮
宇航材料工艺
doi:10.3969/j.issn.1007-2330.2015.04.018
采用流变仪、DSC、DMA、TGA和介电性能测试方法研究了用于RTM工艺的改性氰酸酯树脂的流变、固化反应特性、耐热性和介电性能.结果表明:改性氰酸酯树脂在90 ～ 170℃温度范围内黏度＜500 mPa·s,90℃时黏度为280mPa·s,适用期＞10 h;固化反应活化能为39.5 kJ/mol,反应级数为0.89;树脂固化后玻璃化转变温度为294℃,热分解温度为420c℃;9.375 GHz的介电常数为2.85,损耗角正切＜5×10-3.
关键词:
RTM
,
氰酸酯树脂
,
流变特性
,
玻璃化转变温度
,
介电性能
张剑
,
杨洁颖
,
张天翔
,
裴雨辰
宇航材料工艺
doi:10.3969/j.issn.1007-2330.2015.04.015
以空心石英纤维(HSF)和聚芳基乙炔(PAA)树脂为原料采用RTM工艺制备了空心石英纤维增强聚芳基乙炔树脂基复合材料(HSF/PAA),比较了HSF/PAA与实心石英纤维增强聚芳基乙炔树脂基复合材料(SF/PAA)的力学性能、介电性能及不同纤维增强体形式对材料力学性能的影响.结果表明,HSF/PAA具有较好的高温力学性能和优异的介电性能,使用温度可达450℃,而且通过对纤维增强体形式的优化有望进一步提高该类材料的综合性能.尽管HSF/PAA的高温力学性能仅有同结构SF/PAA的55％～75％,但其在较宽的温度和频率范围内均具有更低的介电常数(3.1)和介质损耗角正切值(0.004),在实际应用中可以获得更高的传输系数和更宽的壁厚容差,有望在耐高温透波材料在航空航天等诸多领域获得应用.
关键词:
空心石英纤维
,
树脂传递模塑
,
聚芳基乙炔
,
复合材料
,
力学性能
,
介电性能
杜勇
,
黄金亮
,
顾永军
,
李丽华
功能材料与器件学报
采用化学共沉淀法制备ZnNb2O6超细粉体,所得的粉体经煅烧压制后通过微波和常规烧结工艺制备ZnNb2 O6陶瓷,并研究两种烧结方法对ZnNb2O6陶瓷相对密度、物相、表面形貌、介电性能等的影响.结果表明,共沉淀法制得的ZnNb2O6粉体晶粒细小、均匀,近似棒形,尺寸约为150nm;与常规烧结工艺相比,采用微波烧结工艺可将ZnNb2O6陶瓷烧结温度降低约150℃,烧结时间缩短1.5h,进而有效抑制了烧结过程中锌元素的挥发;微波烧结后的ZnNb2O6陶瓷晶粒粒径约为6μm,排列均匀,且气孔率低;微波烧结可有效改善ZnNb2O6陶瓷的微波介电性能,与传统烧结方式对比,微波烧结可提高εr和Q ×f为4.6％和15.6％左右,丁f更趋于正值方向.同时对微波烧结陶瓷介电性能进行了较为系统的理论分析.
关键词:
共沉淀法
,
微波烧结
,
传统烧结
,
ZnNb2O6陶瓷
,
介电性能
肖伟玲
,
肖鹏
,
周伟
,
罗衡
,
李杨
宇航材料工艺
doi:10.3969/j.issn.1007-2330.2015.03.008
采用CVD法制备了SiC涂层包覆短碳纤维,并通过凝胶注模成型工艺制备了(SiC) Cf/Si3N4复合陶瓷,探讨了烧结温度对复合陶瓷中(SiC) Cf形貌的影响.同时研究了(SiC) Cf的含量对复合陶瓷力学以及介电性能的影响,当(SiC) Cf含量达到10wt％时,样品的抗弯强度比纯Si3N4陶瓷降低了112 MPa,但断裂韧性显著提高,增加了11.5 MPa·m1/2,介电常数实部和虚部达到最大,介电实部约为15～18,虚部约为6～8;反射衰减随(SiC)Cf的含量和厚度的增加而向低频移动.
关键词:
SiC
,
Cf
,
Si3N4
,
力学性能
,
介电性能
陈聪慧
,
何凤梅
,
李恩
,
杨景兴
宇航材料工艺
介绍了用于毫米波段的介电性能测试的高Q腔法和准光腔法的原理及物理模型,并分别对其进行了仿真分析,建立了相应的测试装置,进行了空腔和石英玻璃的测试.结果表明,准光腔法要比高Q腔法在品质因数、可分辨的频点、样品尺寸、测试精度等方面更有优势.
关键词:
高Q腔法
,
准光腔法
,
毫米波段
,
介电性能
Huarui XU
,
Huaiying ZHOU
,
Aibing YU
材料科学技术（英）
The synthesis of nanosized, homogeneous Ba(Ti0.8Zr0.2)O3 (BTZ) powders from cheap raw materials BaCl2, TiCl4, and ZrOCl2 can be achieved by a simple precipitation process operated at a temperature less than 100℃. Characterization via scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) analysis confirms that the as-prepared powder is ~100 nm with a narrow size distribution. It is also well dispersed because the particle size from SEM observation is almost the same as from BET calculation. Characterization via powder X-ray diffraction (XRD) confirms that the phase of the as-precipitated powder is not the simple mixture of BaTiO3 and BaZrO3 phases but is clearly crystallized as monophasic Ba(Ti0.8Zr0.2)O3 (BTZ) and no other phases have been detected, although the initial concentration ratio of [BaCl2]/[TiCl4+ZrOCl2] varies from 1.0 to 2.0. The dielectric behavior of as-prepared BTZ powder is then investigated and it is found that the change in the dielectric constant during the tested temperature does not exceed 30% and with very low dissipation factor. So, the as-prepared BTZ powder is suitable for MLCC.
关键词:
BTZ
,
null
,
null
郭颖
,
刘锋
,
陈聪慧
,
王立敏
,
赵彤
宇航材料工艺
doi:10.3969/j.issn.1007-2330.2015.06.010
采用二烯丙基双酚A和二苯甲烷型双马来酰亚胺与双酚A型氰酸酯共聚,以改善氰酸酯树脂的工艺和耐热性能;利用DSC,TGA,DMA表征了树脂的固化行为和耐热性能;此外,还研究了树脂的力学性能及高频下的介电性能.结果表明,改性后的氰酸酯树脂固化反应温度降低了约60℃,改性树脂固化物在氮气气氛下Td5约400℃,Tg约270℃,显示了良好的耐热性能.在7～15 GHz宽频范围下,改性树脂的介电常数＜3,介电损耗0.008～0.01,显示了良好的介电性能.
关键词:
氰酸酯
,
双马来酰亚胺
,
介电性能
