高分散体系探究对高梯度氧化锌电阻片性能的影响

为改善ZnO电阻片综合电气性能,尝试一种马来酸酐及聚氧丙烯烷基醚作为结构单元的共聚物做分散剂,考察了其对料浆分散性、压敏电阻显微结构与综合电气性能的影响.结果 表明:分散剂用量为0.4 wt％时,总浆料的粘度较小,Zeta电位绝对值最高,得到的氧化锌瓷体的针孔率最小,ZnO高梯度氧化锌电阻片综合性能最佳,其电位梯度为336 V/mm,漏电流1μA,非线性系数达到55.9,压比为1.667,2 ms方波电流测试中能够承受18次300 A脉冲电流的冲击.     

NiTi合金表面液相阴极等离子体沉积氧化铝陶瓷涂层的研究

在NiTi合金表面通过液相阴极等离子体技术制备了氧化铝(Al2O3)陶瓷涂层。采用X射线衍射和扫描电镜对涂层的相组成以及表面形貌进行了表征和分析,证实在材料表面形成了由α-Al2O3和γ-Al2O3组成的涂层,发现涂层具有粗糙多孔结构。在模拟体液中对NiTi合金的Ni离子释放情况进行了检测,发现液相阴极等离子体改性后显著降低了Ni离子的释放。为NiTi合金植入体的表面改性提供了一条新途径。     

Surface Modification of NiTi Alloy via Cathodic Plasma Electrolytic Deposition and its Effect on Ni Ion Release and Osteoblast Behaviors

To reduce Ni ion release and improve biocompatibility of NiTi alloy, the cathodic plasma electrolytic deposition (CPED) technique was used to fabricate ceramic coating onto a NiTi alloy surface. The formation of a coating with a rough and micro-textured surface was confirmed by X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy, respectively. An inductively coupled plasma mass spectrometry test showed that the formed coating significantly reduced the release of Ni ions from the NiTi alloy in simulated body fluid. The influence of CPED treated NiTi substrates on the biological behaviors of osteoblasts, including cell adhesion, cell viability, and osteogenic differentiation function (alkaline phosphatase), was investigated in vitro. Immunofluorescence staining of nuclei revealed that the CPED treated NiTi alloy was favorable for cell growth. Osteoblasts on CPED modified NiTi alloy showed greater cell viability than those for the native NiTi substrate after 4 and 7 days cultures. More importantly, osteoblasts cultured onto a modified NiTi sample displayed significantly higher differentiation levels of alkaline phosphatase. The results suggested that surface functionalization of NiTi alloy with ceramic coating via the CPED technique was beneficial for cell proliferation and differentiation. The approach presented here is useful for NiTi implants to enhance bone osseointegration and reduce Ni ion release in vitro.     

NiO含量对ZnO压敏电阻性能的影响

研究了不同NiO含量对ZnO基压敏电阻微观结构、相组成电学性能的影响.结果 表明,掺杂合适含量的NiO能够有效的改善ZnO基压敏电阻的电气性能,这可被归因为NiO的掺杂能够调整ZnO的晶粒取向,从而使ZnO压敏陶瓷形成了更加均一的显微结构.CE5样品(NiO摩尔分数为1.55％)具有优秀的综合电气性能,其电位梯度为184.00 V/mm,非线性系数α为72.7,漏电流为0.45 μA,在20 kA和30 kA下的压比分别为2.20和2.38.此外,在20组20 kA及2组30 kA脉冲浪涌电流冲击后,CE5也仍然显示出最优的电气性能.