It was reported that TiB2 gains grew fast during sintering was a main cause for its properties degrading. In this paper the HP-sintering mechanics of TiB2 was studied and the results show that grains grow very fast when the sintering temperature is near 1800℃ . From the sintering dynamics, it can be concluded that grain fast growing results in boundary-transporting processing, during which grain boundary work as fast tunnel for material transporting.
This paper studies the temperature distribution of BN, an insulating material, sintered in the Spark Plasma Sintering ( SPS) system. The temperature distributions of BN at different heating rates were measured , which showed that seeking for an over high heating rate in SPS is not as desirable as controlling of a suitable heating rate in order to have a fast sintering with a uniform temperature distribution.
The crude drug of Liuwei Dihuang was pulverized to nano particles to improve its bioavailability. The appropriate technique parameters were studied. Paeonol, typical marker of Liuwei Dihuang , was extracted with organic solveat in ultrasonic and its content was determined by HPLC. The appropriate techrdques parameters are as follows ： rotating speed control 1200 r/ min , grinding time control 50min and mass percent concentration control 3.8% . The experimental results show that the average particle diameter is 161.9 nm and the great majority of the plant cell wall is broken into pieces after nano pulverization. The extraction efficiency of paeonol is increased by 23.5% .
Titanium diboride based composites, good candidates for contact materials, have high hardness, Young＇s modulus, high temperature stability, and excellent electrical, thermal conductivity. However a good interface of TiB2/Cu is very difficult to achieve for oxidation of TiB2. To avoid this oxidation behavior, the in situ combusting synthesis technology, SHS, was used to prepare TiB2/Cu composite. The characters of Ti-B-xCu SHS were studied in detail, such as combustion temperature, products phases and grain size. Based on the experimental results a proper technology way of self-high temperature synthesis plus quick press （SHS/QP） was determined and compact TiB2/Cu composites with relative density over than 97 pct of the theoretical were fabricated by this method. The properties and microstructures of these TiB2 based composites were also investigated.
Jinyong ZHANG+, Zhengyi FU and Weimin WANGState Key Lab of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China
