The green sheets with Ni paste as inner electrodes were sintered at 1 320 ℃ for 1 h under a N2/H2 mixing gas at an oxygen partial pressure p(O2)=10-8-10-12 MPa, and then reoxided at 900-1 000 ℃ to form multilayer po...The green sheets with Ni paste as inner electrodes were sintered at 1 320 ℃ for 1 h under a N2/H2 mixing gas at an oxygen partial pressure p(O2)=10-8-10-12 MPa, and then reoxided at 900-1 000 ℃ to form multilayer positive temperature coefficient of resistance(PTCR). During the experiments, electronic characteristic effects of PTC with different thicknesses were contrasted. A certain extending of Ni diffusion is beneficial to the ohmic contact of multilayer PTCR but excessive diffusion is harmful to PTCR. The diffusion was studied by scanning electron microscopy(SEM) and energy-dispersive X-ray spectrometry(EDS). Inter-diffusion of element takes place along the Ni-BaTiO3 interface, especially Ni diffusion to BaTiO3 dominated the process. Furthermore, the degree of Ni diffusion is very severe as ceramic layers are very thin.展开更多
采用溶胶-凝胶法合成了Ni-Mn共掺杂Ba Ti O3纳米粉体,同时研究了工艺参数对其形貌的影响。通过X-射线衍射(XRD)和扫描电子显微镜(SEM)表征手段,分析了Ba Ti O3纳米粉体的结构和组成。实验结果表明,该方法可以制备出单纯的立方相,粒径均...采用溶胶-凝胶法合成了Ni-Mn共掺杂Ba Ti O3纳米粉体,同时研究了工艺参数对其形貌的影响。通过X-射线衍射(XRD)和扫描电子显微镜(SEM)表征手段,分析了Ba Ti O3纳米粉体的结构和组成。实验结果表明,该方法可以制备出单纯的立方相,粒径均匀,颗粒大小在250 nm左右的Ba Ti O3纳米粉体,适量Ni-Mn共掺杂不仅能保持Ba Ti O3立方晶格的稳定性,还能抑制杂质Ba CO3的形成。展开更多
基金Project(60676050) supported by the National Natural Science of ChinaProject(2007TY10) supported by the School of Physics and Electronic Technology and Key Laboratory of Ferroelectric and Piezoelectric Materials and Devices of Hubei Province, China
文摘The green sheets with Ni paste as inner electrodes were sintered at 1 320 ℃ for 1 h under a N2/H2 mixing gas at an oxygen partial pressure p(O2)=10-8-10-12 MPa, and then reoxided at 900-1 000 ℃ to form multilayer positive temperature coefficient of resistance(PTCR). During the experiments, electronic characteristic effects of PTC with different thicknesses were contrasted. A certain extending of Ni diffusion is beneficial to the ohmic contact of multilayer PTCR but excessive diffusion is harmful to PTCR. The diffusion was studied by scanning electron microscopy(SEM) and energy-dispersive X-ray spectrometry(EDS). Inter-diffusion of element takes place along the Ni-BaTiO3 interface, especially Ni diffusion to BaTiO3 dominated the process. Furthermore, the degree of Ni diffusion is very severe as ceramic layers are very thin.
文摘采用静电纺丝法制备了平均直径分别为180 nm和220 nm的BaTiO3（BTO）和Ni0.4Co0.2Zn0.4Fe2O4（NCZFO）纳米纤维,使用X射线衍射（XRD）、场发射扫描电镜（FESEM）和矢量网络分析仪（VNA）对纤维的物相结构、表面形貌和微波电磁参数进行了表征,并根据传输线理论分析评估了以BTO和NCZFO纳米纤维为吸收剂的硅橡胶基单层和双层结构吸波涂层在2~18 GHz范围内的微波吸收性能。结果显示,由于BTO纳米纤维的介电损耗与NCZFO纳米纤维的磁损耗的有机结合和阻抗匹配特性的改善,以NCZFO纳米纤维/硅橡胶复合体（S1）为匹配层、BTO纳米纤维/硅橡胶复合体（S2）为吸收层的双层吸波涂层比相应单层吸波涂层表现出更为优异的吸收性能。通过调节匹配层与吸收层的厚度,在4.9~18 GHz范围内反射损耗可达–20 d B以下;当吸收层和匹配层的厚度分别为2.3 mm和0.5 mm时,最小反射损耗位于9.5 GHz达–87.8 d B,低于–20 d B的吸收带宽为5 GHz。优化设计的NCZFO/BTO纳米纤维双层吸波涂层有望发展成为一种新型的宽频带强吸收吸波材料。
文摘采用溶胶-凝胶法合成了Ni-Mn共掺杂Ba Ti O3纳米粉体,同时研究了工艺参数对其形貌的影响。通过X-射线衍射(XRD)和扫描电子显微镜(SEM)表征手段,分析了Ba Ti O3纳米粉体的结构和组成。实验结果表明,该方法可以制备出单纯的立方相,粒径均匀,颗粒大小在250 nm左右的Ba Ti O3纳米粉体,适量Ni-Mn共掺杂不仅能保持Ba Ti O3立方晶格的稳定性,还能抑制杂质Ba CO3的形成。
