In this paper, the structure and ielectric properties of BaO-TiO2 system ceramics were studied. By adding ZnO and Nb2O5 as sintering agents to the raw materials, the BaO-TiO2 system ceramics were sinteredat a temperature of 1260℃ for 2 hand have superior dielectric properties at 1 GHz: quality factor Q=12,500, relative dielectric constant "r37, temperature coefficient of dielectric constant "=0.30 ppm/℃. XRD pattern shows that the main crystal phase of the ceramics is Ba2Ti9O20, accompanied by a small number of additional phases: BaTi4O9, Ba4Ti13Zn7O34, Ba4Ti13O30 andTi 2Nb10O29, etc. The initial Ba/Ti ratio has a great effect on the dielectric properties of the ceramics, which can be explained by the variance in the formation of phases due to different Ba/Ti ratios.

Sn-doped BaO-TiO-ZnO (BTZ) microwave ceramic materials were investigated as a unction of SnO2 eontent. Addition of a small amounl of SnO2 (0.01-0.06 wt%) owered the sin(cring temperature of the system to 1160℃ and also greatly reduced he dielectric loss (tail δ), which is closely related to the insulation resistivity The n-doped BTZ materials were found to have excellent dielectric properties at 1 GHz ith dielectric constant e=36. loss tangent tan δ≤1×l0-4, lemperature coefficienl of dielectric constant, α, =0±30ppm/℃, and volunme resistivty pg≥1013Ωcm.

用回归分析方法得到了（Zr0.7Sn0.3）TiO4陶瓷的介电性能ε和δ与其工艺参数（CuO、ZnO）和玻璃的添加置（分别为x1、x2、x3 wt%）及预烧和烧结温度（分别为x4×103和x5×103℃）之间的定量关系：ε=10.9731-1.4559x+9.9154x2+1.9776x3-3.3160x22-0.2286x23-200.1697x24-161.9102x25+375.1160x4x5；Ig（tanδ）=-38.5876-0.6452x2+0.1235x3+31.2221x4+30.3861x5+0.1100x21+0.2077x22-0.0106x23-27.4317x4x5。能对给定工艺参数下的介电性能进行预测，并能确定满足特定介电性能的工艺参数，有助于加快电子陶瓷材料的研究。

建立三维模型，用蒙特卡洛有限元法对两相复合介质的内部电场分布进行模拟，并由此计算出介质的宏观介电常数εm。发现由三维模型计算出的低介相中的电场能量占总能量的比例高于二维模型。三维模型符合实际复合介质中微粒间并联程度大于串联程度的事实，因此由三维模型得出的电场分布和εm值比二维模型更加精确。得出了新的两相复合介质宏观介电常数预测公式：εαm=V1εα1+V2εα2，其中α=(V21+20V1V2+5V22)/111V1+V2=1，ε1<E2。该公式与若干文献中的实验结果相吻合。

利用无压渗透法制备出SiCp/Al复合材料，研究了SiCp/Al系统的界面微观结构及复合材料的机械性能。研究表明：SiCp/Al系统的界面处存在着界面反应，生成Si、Al2O3和Al3C4等产物，在界面处存在着Si和Mg元素的富集；复合材料的机械性能受界面反应和Si元素富集的影响，其中界面反应是最重要的影响因素。当界面反应控制在一定程度时，在基体与增强相的界面处形成比较充分的“机械绞合”，才会使复合材料的机械性能有较大提高。界面上Si元素的富集对机械性能的影响较为复杂，一方面它可以控制界面反应的过度发生，另一方面又会产生晶格畴变，这两方面效应的叠加，使之对复合材料机械性能的影响减弱，远小于界面反应对机械性能的影响。