The paper presents a brief derivation of the temperature distribution in the sample and the die in spark plasma sintering. It aims to point out that temperature difference is inevitable in the samples of SPS system. Under certain conditions, the difference may reach a few hundreds of degrees of centigrade. Experiments also proved the existence of such a difference, which is larger than the one under steady-state temperature distribution.

In this paper, a titanium diboride ceramic was produced by the hot pressing sintering method. The effects of hot pressing parameters on the TiB2 ceramic microstructure and mechanical properties were studied. The bending strength and fracture toughness were measured by three point bending testing and single edge notched bending tests (SENB), respectively. The microstructure features of the TiB2 sintered material were revealed by means of SEM and TEM. The results show that the TiB2 grain size increases quickly with the increasing temperature and time during hot pressing sintering. The density and the TiB2 grain size have a great influence on the mechanical properties. The bending strength decreases with increasing TiB2 grain size, whilst the fracture toughness increases.

Powder mixtures of Al2O3, ZrO2, Ni were sintered by pulse electric current sintering at 1300 8C with a heating rate of 200 8C/min or 130 8C/min. Large ZrO2-Ni agglomerates are formed within the Al2O3 matrix after sintering. Depending on the heating rate, these agglomerates formed networks within the matrix. The networks are heterogeneously distributed in the specimens prepared by the heating rate of 200 8C/min but homogeneously in the specimens prepared by the heating rate of 130 8C/min. The microstructure evolution of the specimen prepared by the heating rate of 200 8C/min indicates that the temperature at the edge of the specimen is higher than that at the center. The temperature difference is smaller for the specimen prepared by the heating rate of 130 8C/min. The small ZrO2 particles tend to associate with nickel melt to form ZrO2-Ni agglomerates. Then the ZrO2-Ni agglomerates are migrated by magnetic field that induced by the pulse electric current.

Self-propagating high-temperature synthesis (SHS) is a promising method for the fabrication of composites. However, the products obtained directly from the SHS process are generally porous, which limits the application of SHS. SHS plus dynamic mechanical pressing, which combines synthesis and densification in one step was proposed and was named SHS/QP. In the process, immediately after the SHS reaction, a quick pressing force acts on the hot and soft sample for densification. In this paper, the fabrication of cermets by SHS/QP is reported. The optimum conditions of SHS/QP for cermets were studied, and the densification mechanism for cermets was analyzed.

In this paper, combustion synthesis method was used to synthesize TiB2 ceramic powder from various oxides. Thermal analysis methods were employed to reveal the chemical reaction processes, a high-speed image recorder was used to monitor and analyze the features of combustion processes. Study results indicated that in B2O3-TiO2-Mg system, B2O3 was reduced to elemental B and MgB2 in one step and TiO2 was reduced to element Ti through following steps: TiO2→Ti3O5→Ti2O→Ti, and then, TiB2 was formed by reaction Ti＋2B→TiB2 and Ti＋MgB2→TiB2＋Mg. In synthesis processing, Mg plays a important role in controlling the mineral phase component of synthesized production and combustion processing. The propagating combustion wave model was found to become unstable with increasing diluent additive amount in raw mixture.