TiB2/B4C composite ceramics are prepared via hot pressing, in which the TiB2 particles are formed by introducing TiC0.78 and through the reaction between B4C and TiC0.78. The electrical and thermal conductivities and Seebeck coefficient of samples containing 0, 12.5 and 25.4 vol% TiB2 are measured from room temperature up to 1200K. The results show that the transport properties of the samples vary with the TiB2 content. The transport properties of a 12.5 vol% TiB2/B4C sample are dominated by the B4C matrix as in undoped B4C ceramics, whilst the transport properties of a 25.4 vol% TiB2/B4C sample are dominated by TiB2 particles. The figure of merit of the 25.4 vol% TiB2/B4C sample is higher than that of the undoped B4C ceramic sample between room temperature and about 700K, which indicates that it is possible to improve the thermoelectric properties by selecting an optimum combination of different materials.

Al2O3 added ZnO powders were prepared via sol-gel processing, using zinc acetate, ammonia and Al2O3 powders as starting materials. Scanning electron microscopy (SEM) observations indicated that the Al2O3 added ZnO powders consisted of very fine particles (0.1-2m). The thermal conductivity, electrical conductivity and Seebeck coefficient of hot-pressed Al2O3 added ZnO ceramic samples were measured in dependence of temperature up to 600℃. The influence of Al2O3 addition on the thermoelectric (TE) properties of ZnO ceramics is discussed.

A B4C ceramic doped with 0.2 at% Si is prepared via hot pressing. The composition and microstructure of the ceramic are characterized by means of X-ray diffraction (XRD) and electron probe microanalysis (EPMA). The electrical conductivity and Seebeck coefficient of the ceramic samples are measured from room temperature up to 1500 K. The electrical conductivity increases with temperature; the Seebeck coefficient also increases with temperature and rises to a value of about 320μV K-1 at 1500K. The value of the figure of merit of 0.2 at% Si-doped B4C is higher than that of undoped B4C and rises to about 1×10-4K-1 at 1500K. The reason for enhancement in the figure of merit of Si-doped B4C is discussed.

AlON-TiC composites were fabricated via a reaction-bonding technique, using Al, Al2O3 and TiC powders as the starting materials. A composite sample sintered at 1850℃ after nitriding is highly densified and the Vickers hardness and fracture toughness of the sample are about 1751.1 kg/mm2 and 5.3 MPa m1/2, respectively. The composition and microstructure of the sample are characterized by means of XRD and SEM/EDX.

β-FeSi2-TiB2 composites with various amounts of TiB2, from 0 up to 30 vol%, were prepared by hot pressing. The electrical and thermal conductivities, and the Seebeck coefficient were measured as a function of temperature. The results show that the thermal and electrical transport behavior of the composites is different as the volume fraction of TiB2 is below and above about 0.255. A 5 vol% TiB2 added sample has higher figure of merit than one without TiB2 for temperatures above 650K. The influence of an additional phase, 1-FeSi, formed during the hot pressing, on the thermoelectric properties of the b-FeSi2-TiB2 composites was also discussed.