Silicon nitride (Si3N4) powders were synthesized with silica sol, urea and carbon black by ammono sol2gel processing. Urea was dissolved in water and mixed homogeneously with silica sol. Ammonolysis of the aqueous solution could form a precursor, which was then mixed with carbon black and nitrided at 1300～1600℃under a flowing N2 atmosphere. The precursor and final powder were characterized by X-ray diffractometry, infrared spectroscopy and transmission electron microscopy. Results showed that Si3N4 powders with a size of 50～80nm and a content of more than 37% nitrogen can be obtained from the precursor annealed at 1500℃under a N2 flow of 3L/min for 2h. Effects of ammonolysis and synthesizing conditions on the final products were investigated.

Al2O3陶瓷在800℃以上高温下的磨损明显减小，在摩擦表面形成了由极细晶粒构成的表面层。为了探讨这种表面层的形成机理，研究了Al2O3/Al2O3摩擦副在800～1200℃下于干摩擦时的塑性变形与再结晶，且用表面层厚度和晶粒大小来表征。表面层厚度和再结晶粒子尺寸均取决于试验温度、表观接触压力和滑动速度。根据对应变速率和摩擦表面温度的测算，发现再结晶粒子尺寸与Zener2Hollomon常数Z的对数存在良好的线性关系，说明Al2O3陶瓷在高温磨损中的再结晶属动态再结晶。由塑性变形引发的动态再结晶是导致表面层形成的主要机理。

研究了碳化硅陶瓷在空气和真空环境中从室温至1200℃的摩擦磨损特性。摩擦系数对温度的依存性取决于接触压力和气氛。当接触压力为1.2MPa时，摩擦系数几乎与温度无关，但在空气中的摩擦系数明显大于在真空中的。比磨损率也与温度、气氛和接触压力密切相关。实验中观察到了三种磨损模式，其比磨损率分别随温度的升高而呈现增加、基本不变和减少的趋势。在高温和0.2MPa接触压力下获得了低的磨损，但在高温和0.4MPa接触压力下的磨损却显著增大。表面剥离和塑性变形是碳化硅在高温下的主要磨损机理。

The adsorption of poly(acrylic acid) (PAA) in aqueous suspension onto the surface of TiO2 nanoparticles was investigated. FTIR spectroscopic data provided evidence in support of hydrogen bonding and chemical interaction in the case of the PAA–TiO2 system. Adsorption isotherms demonstrated that part of the PAA initially added to the suspension was adsorbed onto the TiO2 surface, after which there was a gradual attainment of an adsorption plateau. The adsorption density of PAA was found to increase with an increase of PAA molecular weight, while it decreased with an increase of pH. The thickness of the PAA adsorption layer was calculated based on measurements of suspension viscosities in the absence and presence of PAA. It was shown that the thickness of the adsorption layer increased with the increase of pH, PAA molecular weight, and its concentration. The surface charge density, the diffuse charge density, and the zeta potential of TiO2 varied distinctly after PAA adsorption. The shift of pHiep toward a lower pH value was observed in the presence of PAA. PAA was found to stabilize the suspension of TiO2 nanoparticles through electrosteric repulsion. The influence of factors such as PAA molecular weight and its concentration on the colloidal stability of the aqueous suspension was also investigated.

The colloidal stabilization of nano-sized zinc oxide suspensions with maleic anhydride sodium salt copolymer is examined to understand the primary mechanism of dispersion. FTIR spectroscopic data provided evidence in support of hydrogen bonding and chemical interaction in the case of the MA-Na copolymer/ZnO system. The suspension stability was characterized by sedimentation tests and TEM method. The copolymer was found to stabilize the suspension of ZnO nanoparticles through electrosteric repulsion. Influences of factors such as pH and the copolymer concentration on the colloidal stability of aqueous suspension were investigated. The copolymer at high pH of the solution provided more effective degree of sustained particle dispersion. The adsorbed MA-Na copolymer provided a good stabilization under the saturated adsorption amount, while the excess copolymer flocculated the dispersed system.