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Using SnCl2 • 2H2O and SnCL • 5H2O as tin source and polyvinylpyrrolidone (PVP) as polymer matrix, fibril was prepared by using simple and controllable electrostatic spinning technology, and SnO2 nanofibers were obtained after calcination. Scanning electron microscope (SEM), X-ray diffractometer (XRD) etc. were used to investigate the effect of PVP molecular weight and different tin sources on the morphological properties of SnO2 nanofibers, and the specific surface area and gas-sensing characteristics of SnO2 nanofibers were tested. The results show that the fiber precursor prepared by electrospinning can remove the polymer matrix and solvent after ca lei nation, and obtain pure tetragonal rutile SnO2 nanofibers, which show the characteristics of large specific surface area, high sensitivity and fast response speed. When PVP-K30 is used as high molecular matrix and SnCL4 • 5H2O is used as tin source, the prepared SnO2 nanofibers have uniform diameter, clear fiber, good orientation and better gas sensing characteristics. [ABSTRACT FROM AUTHOR]

Ag-SnO2 composite powder was prepared by sol-gel method using Sn powder and AgNO3 as raw materials, citric acid as reductant and complexing agent and soluble starch aqueous solution as template. Subsequently, Ag-SnO2 electrical contact alloys were prepared using Ag-SnO2 composite powder as material by powder metallurgy. The obtained Ag-SnO2 composite powder and alloys were characterized through XRD and SEM. The decomposition process of starch paper precursor was analyzed via TG-DSC. Meanwhile, the microstructure and properties of Ag-SnO2 electrical contact alloys with different citric acid contents were also investigated. The results show that Ag-SnO2 electrical contact alloy is in good agreement with the tetragonal rutile SnO2 and face-centered cubic Ag, and the template has been removed without any impurities. SnO2 powder was uniformly dispersed in Ag matrix with the help of starch template. With the increasing of citric acidcontents, the physical properties of Ag-SnO2 electric contact alloy increased at first and then decreased. And the physical properties of Ag-SnO2 electrical contact alloy are the best when the ratio of n(C6H8O7):n(Ag++Sn4+)is 3:1. [ABSTRACT FROM AUTHOR]