Al对等离子放电烧结法合成Ti3SiC2的影响研究

以元素为原料，Al为助剂，采用等离子放电烧结(SPS)工艺合成Ti3SiC2块体材料，通过X射线衍射分析和对SPS过程参数的研究表明：适量A1能促进Ti3SiC2的反应合成，提高合成材料的纯度，但Al也会使Ti3SiC2的热稳定性降低。     

以铝为助剂结合放电等离子烧结制备Ti3SiC2

以铝为助剂结合放电等离子烧结工艺,在较低温度下快速制备出高纯致密Ti₃SiC₂块体材料,掺加适量铝能加快Ti₃SiC₂的反应合成,提高制备材料的纯度,并促进Ti₃SiC₂晶体的生长和材料的快速烧结致密,在升温速率为80℃/min,z轴压力为30MPa时,材料制备的最佳温度为1200～1250℃,所制备材料经XRD、SEM和EDS分析表明不含TiC和SiC等杂质相,Ti₃SiC₂为5～25μm的板状结晶。     

放电等离子烧结Cu/Ti3AlC2的电性能及力学性能

以Ti3AlC2和Cu粉作为原料,使用放电等离子烧结制备Cu/Ti3AlC2复合材料,研究了不同烧结温度对复合材料的影响。结果表明,在750~800℃之间,Cu与Ti3AlC2之间会发生反应生成TiC相。同时随着温度在650~850℃不断增加,密度和抗弯强度不断增加在850℃达到最大值分别为8.33 g·cm^-3和531.4 MPa,而电阻率先减小在750℃达到最小值1.98×10^-7Ω·m后增加在850℃达到最大值6.47×10^-7Ω·m。Cu/Ti3AlC2复合材料性能随着温度的变化与其致密度和反应生成TiC有着密切的联系。     

原位插层聚合尼龙6/超分散有机蒙脱土剥离型纳米复合材料的结构和性能

采用原位插层聚合法制备了尼龙6/蒙脱土剥离型纳米复合材料,讨论了超分散有机蒙脱土的用量对复合材料性能的影响,用动态力学分析(DMA)、X射线衍射(XRD)、扫描电镜(SEM)和透射电镜(TEM)等手段研究了纳米复合材料的结构和性能。结果表明,有机蒙脱土加入量为3%(质量分数,下同)时,复合材料综合性能最佳;有机蒙脱土的加入大大提高了尼龙6的综合性能,并提高了尼龙6的储能模量和玻璃化温度。有机蒙脱土在尼龙6基体中有良好的分散性和相容性,蒙脱土片层被完全剥离,在尼龙6基体中实现了纳米级分散。     

Ti基功能梯度材料的研究进展

综述了Ti基功能梯度材料的各种制备方法、性能评价以及在航空机械和生物医药等方面的应用,展望了Ti基功能梯度材料的未来发展及前景。     

Microstructure,Densification, Microhardness and Antioxidant Properties of Ti_2AlN/TiN FGM Fabricated by Hot-pressing

Ti2AlN/TiN functionally graded materials(FGM) were successfully fabricated by vacuum hotpressing. Bulk density of the sintered samples was measured by Archimedes principle. The sample sintered at 1 300 ℃ for 2h has the maximum final density and lowest open porosity. SEM coupled with EDS was utilized to investigate the phase composition and microstructure, and well-formed boundary was found between the layers. The microhardness tests suggest that Vickers' hardness of Ti2AlN/TiN FGM increases monotonically with the volume fraction content of TiN increases. Corrosion results are that the corrosion resistance of Ti2AlN/TiN FGM is much better than that of Ti2AlN in acid, but quite the opposite in alkali. Constant temperature oxidation study shows that the oxidation kinetics of Ti2AlN/TiN FGM at 900 °C follows the parabolic law closely.     

Physical, antioxidant and thermal shock properties of Cu/Ti2AlC conductive composites

Cu/Ti₂AlC composites were fabricated by vacuum hot-pressing technique. Phase composition was analyzed by XRD and morphology of fracture was observed by SEM. Physical performance such as density, resistivity, hardness and friction coefficient with different volume fraction of Cu/Ti₂AlC composites were studied. When the content of Ti₂AlC increased from 10% to 70%, the relative density reduced from 99.38% to 90.56% and the resistivity increased significantly. Hardness reached the maximum value when Ti₂AlC was at 60% and friction coefficient declined with the increasing of Ti₂AlC. Cu/Ti₂AlC composites, showing good conductivity properties and friction performance. Oxidation resistance enhanced obviously with the content of Ti₂AlC increasing. Cu-60%Ti₂AlC sample possessed optimum thermal shock resistance, and no cracking was found at 600 °C cycled for 10 times and 900 °C cycled for 1 time.     

放电等离子烧结含铝Ti3SiC2相的形成规律研究

用放电等离子烧结工艺以元素粉为原料制各Ti3SiC2材料时，掺入适量铝能改善Ti3SiC2的反应合成。应用X--射线衍射和扫描电子显微镜研究不同烧结温度下材料的相组成和显微结构特征。结果表明：含铝Ti3SiC2相在1100℃开始大量形成，经1150一1250℃烧结，能制备纯净致密含铝Ti3SiC2固溶体材料。铝的固溶降低了Ti3SiC2的化学热稳定性．使其分解温度降低至1300℃。     

油井土、废玻璃基多孔陶瓷的制备及结构表征

利用油井土、废玻璃作为主要原料,同时以碳酸钙作为造孔剂,通过控制烧结过程,最终制备多孔陶瓷材料,并利用XRD、SEM等对样品进行结构表征。本研究的目的是为了研究油井土、废玻璃、碳酸钙的比例以及烧结温度对孔隙率、机械强度、体积密度、吸水率、微观结构和结晶程度的影响。结果表明样品A3呈现大孔均匀的微观结构,是通过添加35wt％油井土、40wt％废玻璃、20wt％碳酸钙、5wt％硅酸钠在较低的烧结温度下来获得,其孔隙率、抗压强度、抗弯强度、体积密度和吸水率的值分别为52．38％、4．43 MPa、12．59 MPa、1．07 g／cm3和29．56％。并观察到其机械强度、吸水率和微观结构（孔径及孔径分布）有良好的相关性。     

储热混凝土单元设计与储热模拟

设计两种储热结构单元,采用ansys动态模拟方法模拟了在储热过程中储热单元温度最低点温度与时间的关系。研究发现：热导率越大储热速度越快,把钢管由平行排列改为三角错排,储热单元截面则由正方形变为正六边形,面积保持不变,传热性能有所提高;在混凝土中加入5％石墨片强化传热,等效热导率提高了4．7倍,与加5％石墨粉的混凝土相比,等效热导率提高了一倍。