Z.-X. Tang’s scientific contributions

With high-purity Al 2O 3, AlN and Al powders as raw materials and with Y 2O 3 and MgO as singtering additives, forming with cold isostatic pressing in 150 MPa, AlON transparent ceramics were obtained at 1850°C for 1 h under nitrogen atmosphere. The results of experiment indicate that the AlON transparent ceramics have fine grain sizes, uniform grain distribution, and no secondary phrases. Transparent performance in ultraviolet range and visible light range can be distinctly enhanced by using isostatic pressure forming, while transparent performance in infrared light range can not be distinctly enhanced. The total-transmittance in ultraviolet range (200-1100 nm) is 82%, The total-transmittance in infrared light range (1750-5000 nm)is 98%. The density of AlON is 3.70 g/cm 3, which is about 99.7% of its theoretical density.

The thermoelectric effect represents interactions between electrical and thermal transport, that is,a thermal gradient causing an electric field. As a typomorphic characteristic, thermoelectricity of metal-semiconducting minerals can denote the physical-chemical conditions of mineral formation,and therefore can be applied to the exploration and evaluation of ore deposits. In order to probe into the relation between the thermoelectric typomorphic characteristics and prospecting, the principle involved in the thermoelectric effect of minerals and the factors influencing the thermoelectric power are discussed,and the application.of thermoelectric typomorphic characteristics to prospecting is elucidated on the basis of the latest research on minerals from the land deposits and the Pacific Ocean respectively. It is shown that a database of information regarding the determination of basin paleotemperature, the estimation of mineralization, the prediction of concealed ore bodies, the study of metallogenetic zonation, and the evaluation of denudation extent of ore deposits can be obtained through characterizing the thermoelectric effect of minerals.