均相沉淀法制备AACHH阻燃晶须及其生长机理研究

采用均相沉淀法制备了一种新型铝系阻燃晶须AACHH，通过FTIR、TG/DTA、化学分析、XRD、SEM、AFM等手段对AACHH的结构、成分、形貌、结晶过程进行了分析与表征。结果表明：AACHH中阻燃气体释放量为63.8%，其结构分子式为NH₄Al(OH)_3.24(CO₃)_0.38·H₂O，六方晶系，晶胞参数为a₀=1.333 5 nm、c相似文献   

新型无机晶须——钛酸钾晶须

本文介绍钛酸钾无机晶须新材料的研究现状、晶须形貌、结构和性能特点，以及晶须的合成方法。钛酸钾晶须主要应用于塑料与金属的增强，取代石棉和玻璃纤维或与之混合使用以得到高性能的复合材料。     

硼酸镁晶须增强材料的制备和应用

介绍了硼酸镁晶须增强材料在塑料、金属、合金及复合材料等行业的应用,并对当前硼酸镁晶须的制备方法进行了分析和评述。结合作者等对硼酸镁晶须的研究结果,指出了当前研究中存在的缺点和不足。采用改进的制备工艺能够获得长度为30μm,长径比达30~50的硼酸镁晶须。     

熔盐法合成莫来石晶须

Using SiO₂ and Al₂O₃ as raw materials, mullite whiskers were prepared by heating at 1 200 ℃ for 4 h in potassium sulfate flux. The morphology, crystalline characteristics, compositions and growth direction of whiskers were investigated by means of XRD, SEM, EDS and TEM. The results indicate that the as-synthesized whiskers are about 4 μm in length and 0.5～1 μm in diameter, and mullite whiskers grow along c-axis direction ([001] direction). The formation of mullite whiskers is controlled by dissolution-precipitation reactions, and the salt flux method is a good way to grow mullite whiskers.     

MgO晶须的物相组成和微观形貌多样性

采用适当MgO-Al比例物料,压制成型后放入气氛炉中于1500℃烧制6h,最终在样块表面得到 MgO晶须.晶须的物相组成为方镁石,显微结构研究表明多数呈细长的柱状,顶端尖锐,长约600～800μm ,长径比100～200;晶须发育的纹理特征有多种,晶须的横截面有扁六边形、正六边形、菱形和正四边形以及不规则形状等多种,能谱分析表明晶须的形貌与化学组成有关.     

高纯度长径比CaCO3晶须的制备

无机盐晶须材料是高技术新型复合材料中特殊的成员,它具有优良的耐高温、高热、耐腐蚀性能,有良好的机械强度、电绝缘性、轻量、高强度、高弹性模量、高硬度等特性。作为塑料、金属、陶瓷的改性增强材料时显示出极佳的物理、化学性能和优异的机械性能。     

SnO纳米晶须的制备及其性能表征

SnO nanowhiskers were successfully prepared by the pressure thermalcrystallization method using SnCl2·2H2O as raw material, Na2CO3 as mineralizing reagent and cetyltrimethylammoniumbromide as surfactant. Microstructure and morphology of the prepared products has been characterized by means of transmission electron microscopy,selected area electron diffraction and X-ray diffraction. The results showed the particle has rod like apparent structure. The diameter and the length of the particle were 10~40 nm and 100~400 nm, respectively. The influence of some reaction parameters, including the pressure, the surfactant and the reaction duration, on the formation, morphology and particle size of SnO crystallite was discussed. It revealed that increasing the pressure and prolonging the reaction time duration are favorable for the formation of tetragonal stannous oxide whiskers. The mechanism of the formation of SnO nanowhiskers was also simply investigated.     

微米碳化硅晶须在水介质中的分散行为

以去离子水为分散介质,六偏磷酸钠(SHP)和羧甲基纤维素钠(CMC)为分散剂,利用沉降法、ζ电位、傅里叶变换红外光谱(FTIR)、TEM等测试技术研究了微米碳化硅晶须在水介质中的分散稳定机制,探讨了pH值、分散剂种类及含量对SiC微米晶须分散行为的影响机制。结果表明:微米SiC晶须的分散机理为静电稳定机制,pH值、SHP和CMC对微米SiC晶须的分散性和稳定性有较大影响;pH值为11时,微米SiC晶须的分散性和稳定性较好;SHP和CMC含量均为4wt%时,SiC微米晶须悬浮液具有良好的分散性能,分别在沉降时间18.5 h和22 h时相对沉降高度仍达96.89%和98%。六偏磷酸钠的分散机制主要以提高颗粒间的静电斥力为主,而羧甲基纤维素钠则为增大晶须表面的亲水性和提高晶须表面的电位绝对值。     

室温下激发强度对ZnO晶须发光的影响

采用浮区法(FZ)在高氧压条件下生长出大尺寸的ZnO单晶晶须.X射线衍射(XRD)和拉曼光谱(Raman)分析结果表明,生长的ZnO单晶晶须为六方结构晶体,沿(100)晶面方向有明显的择优生长取向.研究了0.3 MPa氧压下生长的ZnO晶须的变功率光致发光光谱,结果表明,晶须在室温下有比较高的紫外光致发光效率和较低的缺陷,其紫外发光激发强度的阈值1 kW/cm2.     

Sm123在Sm211晶须上取向生长研究

通过热力学参数的控制，我们在Sm-Ba-Cu-O的高温熔体中获得了长度可达4．2mm的Sm211晶须．通过SEM、HRTEM及SCXD等表征手段，对晶须的表面形貌和微观结构进行了分析，并确定其生长方向为晶须的〈001〉方向．通过高温金相显微镜，我们原位观察到Sm123晶体在Sm211晶须上按照特定取向生长．本文对Sm123与Sm211的取向关系进行了探讨．