烧结气氛对合成MgAl2O4-Ti(C,N)复合陶瓷的影响

以金属铝粉、钛白粉和轻烧MgO细粉为原料,通过设计100%焦炭粒(简称C气氛),10%钛白粉 90%焦炭粒(简称TC气氛),以及10%硅微粉 90%焦炭粒(简称SC气氛)3种埋粉条件下的高温烧结还原性气氛,采用X射线衍射仪(XRD)、扫描电镜(SEM)和微区电子探针分析(EPMA)等手段,研究了铝热还原氮化法(1600℃3h)制备MgAl2O4-Ti(C,N)复合陶瓷在不同烧结气氛下的相组成和显微结构的变化。结果表明在不同气氛下,烧后试样的主要物相均为MgAl2O4和Ti(C,N),Ti(C,N)可能会固溶氧,气氛对Ti(C,N)的影响较大。和单纯埋炭气氛下相比,在TC气氛下有助于Ti(C,N)的生成,但晶粒细小;在SC气氛下不利于Ti(C,N)的生成,且有玻璃相存在。     

喷射电沉积块体纳米晶Co-Ni合金工艺的研究

利用扫描电子显微镜（SEM），能谱仪（EDS）及X射线衍射（XRD）等分析方法研究了工艺参数对电解液喷射电沉积法制备块体纳米晶Co-Ni合金沉积层成分及结构的影响。结果表明；在本实验条件下，随电解液喷射速度的增加，沉积层中钴含量增加，而晶粒尺寸减小；随电解液温度的升高，沉积层中钴含量减小到一定值后增大，晶粒尺寸呈相反的趋势。沉积层的表面形貌为胞状结构。     

1991—1992国外工程塑料进展

介绍了1991～1992年国外工程塑料研究和生产概况。论述了通用工程塑料、特种工程塑料和聚合物合金的研究开发、改性和应用方面的进展。且指出工程塑料发展趋势和特点;对复合材料技术进展作了较详尽的分析与阐述。     

纤维微粒在电解液中运动方式的模拟

采用Fluent软件提供的离散相模型,重点研究了柱状纤维粒子在电解液流场中的运动情况,分析了溶液参数,如粘度、密度、旋转转速以及颗粒性质对其运动状态的影响.在模拟实验中,建立了磁力搅拌子和板状搅拌子两种搅拌模型.模拟结果表明:溶液粘度为0.2 kg/(m·s)左右,搅拌转速在20～30 rad/s范围内,板状搅拌子模型能够产生稳定的流场.粒子在垂直于搅拌子的平面内基本上作圆周运动,确保在复合电镀过程中,晶须(纤维粒子)将最大程度上以定向的方式被包覆在镀层中.     

ASPECTS OF JOINT DESIGN AND EVALUATION IN THICK-ADHEREND APPLICATIONS

Structural adhesives are gaining wide recognition by industry as they offer engineering designers greater flexibility to achieve economic and technical advantages. In the marine industry there are potential applications for adhesives in various types of construction, for example, thick steel and composite adherends, (typically 5-15 mm thick). The applications include panels and large pipes. This article is largely concerned with the use of two-part epoxy adhesives. The purpose of this article is to understand and evaluate the weaknesses of adhesives and adherends, in relation to specific applications and to use design and material selection to alleviate them. This understanding can be extended to other thick adherend applications. This article will also highlight the impact of structural epoxy adhesive technology on the design and fabrication of steel, composite, and hybrid constructions. The benefits and inherent limitations that can accrue are quantified through three case studies related to thick adherend connections.     

玻璃微珠填充PP结构与性能研究

用一步法和二步法两种混合工艺,研究了经过表面预处理的玻璃微珠填充PP的力学性能。结果表明,经过适当表面处理的玻璃微珠可以通过熔融共混均匀分散在PP中,粒子与基体界面结合良好。填充体系随着玻璃微珠含量的增加,拉伸强度增大,冲击强度下降。流动性随着玻璃微珠含量的增加而增大,然后随之下降。     

工艺条件对电沉积Ni-金刚石复合镀层性能的影响

研究了温度、电流密度、pH等工艺条件对镍-金刚石复合镀层性能的影响。实验表明,在金刚石含量为40 g/L的瓦特镀镍液中,当电流密度为1.5 A/dm2、温度为40℃、pH为3.8时,在45#钢上可获得性能较好的镍-金刚石复合镀层,且沉积速率适中。镀层中金刚石微粒含量为11%~13%(质量分数),镀层硬度为2100 MPa左右,耐磨性能较好。     

Electrodeposition of Pd–Ag alloy nanowires on highly oriented pyrolytic graphite

This paper reports findings of an investigation of Pd–Ag alloy nanowires on the step edges of highly oriented pyrolytic graphite (HOPG) by electrochemical deposition at room temperature. Scanning electron microscopy (SEM) images reveal that these alloy nanowires (109–430 nm) are uniform in diameter, and have lengths up to 100–500 μm. The electrodeposition process involves the initial formation of nanowires induced at the step edges of the oxidized HOPG substrate at a very negative potential and subsequent growth at a constant low current density to coalesce the discontinuous nanowires. Alloy nanowires with a 20–25% silver content can be obtained when the ratio of Pd and Ag in the solution is carefully controlled. The SEM images demonstrate that the alloy nanowire arrays are continuous, parallel, ordered, well-aligned and have a narrow distribution of diameters. The Pd–Ag alloy nanowire arrays are promising materials for fabricating hydrogen nanosensors.     

热塑型聚氨酯复合体系力学性能研究

采用压延机，在加工温度不高于１２０°Ｃ的条件下，成功地制备出热塑型聚氨酯弹性体（ＴＰＵ）与高氯酸铵、铝粉及增塑剂邻苯二甲酸二丁酯（ＤＢＰ）等组成的复合胶片，拉伸实验结果指出了所制备的热塑性弹性体复合体系具有良好的力学性能，完全达到或超过推进剂体系的要求指标。     

无卤阻燃高抗冲聚苯乙烯的研制

研究了纳米改性氢氧化铝（CG-ATH）、改性聚苯醚（MPPO）和红磷母料对高抗冲聚苯乙烯（HIPS）的阻燃作用及SBS对所得阻燃材料的增韧作用，得到了具有良好阻燃性能和物理机械性能的复合材料。结果表明，CG-ATH和MPPO与红磷母料之间有很好的协效阻燃作用，配合使用可以使HIPS的垂直燃烧达到FV-0级，氧指数达到27．5％，但是所得复合材料的冲击强度较低。SBS对复合材料有很好的增韧作用，可以使冲击强度提高一倍以上，并且不影响复合材料的阻燃性能。