Studies Of Glass Forming Ability Of Tellurium Based Alloys With Narrow Gap

Compared with the conventional metal materials, amorphous alloy shows outstandingphysical and chemical properties because of its special structure characteristics. Therefore,many scientists working on materials interest it since its appearance. The formed essenceof amorphous solid is that substance in condensing process does not change into crystal. Ifthe cooling rate are high enough, liquid metal could be freezed and maintain the structurecompletely until it become amorphous. This process occurs glass transition.The semiconductor materials based on tellurium are well known because of itsexcellent thermoelectric properties, also we can get the tellurium based alloys with narrowband gap through melt-spining method. Thereby, as a result of low thermal conductivity,the thermoelectric properties will be improved significantly. But in recent years, fewreports. The article is based on the rules of bulk metallic glass forming in multicomponentalloy system and extends it, proposing a method that selecting the appropriate alloycomposition from the point view of thermodynamic, constructing eutectic or like-eutecticsystems on dynamics, using melt-spinning technique to prepare amorphous materialswhich are multicomponent tellurides with a narrow band gap. Based on the Ge-Te, Bi-Te,Sb-Te or other binary system, therefore, constructing like-binary eutectic systems with twotypes of telluride which have a low entropy of fusion such as Bi2Te3、Sb2Te3、In2Te3、Ga2Te3and Cu2Te、Ag2Te、PbTe、CdTe、SnTe、ZnTe. Then, melting them as uniform,making a preparation of bands through rapid quenching, observing the degree ofamorphization and contents by XRD. At last, we have confirmed several systems whichhave excellent glass forming ability, and summarized their characteristics.The following conclusions are obtained that the simple binary system of telluridewith narrow band gap is hard to transform into amorphous, but it shows that rapidquenching plays a positive role in inhibiting crystal nucleation and growing up, also on therefining of crystalline grain. Although, all the systems PbTe-Cu2Te, SnTe-Cu2Te,PbTe-In2Te3etc. appeare to weaken the material characteristic peak in their own differentcomponents of systems. It indicates that the best glass forming region are close to eutectic point in metal alloy systems, with a guiding significance. In the system SnTe-In2Te3, onthe point about35/65, have approached to become perfect amorphous, likewise, the DSCanalysis can show that which is qualitative and indirect. At the same time, we discuss theoptimum technological parameter about melt spinning in-depth. In the systemSnTe-Ga2Te3, we have already prepared fully amorphous samples, and laid a remarkablefoundation for the next step of testing and modification to promote the thermoelectricproperties.