Lihua Gao

Research on Some Aromatic Schiff Base Compounds and Metal Complexes with Different Substituted Groups

Two aromatic Schiff base derivatives and the corresponding metal complexes with different substituted groups were synthesized and characterized by many methods. The products were characterized by UV-Vis spectra, FT-IR spectra and thermal analysis, while the thermal stability was measured by TG-DTA instrument. FT-IR analysis indicated that the nitrogen atom in imino group and oxygen atom in phenolic hydroxyl group participated in coordinating with transition metal ion in different bridged mode. UV spectra also verified that different coordination modes can be performed between metal ions and ligands. In addition, the thermal stability of metal complexes had been obviously superior to that of the ligands. All results give a useful clue to obtain Schiff base derivatives with versatile property by regulating intramolecular substituted group and species of metal ion. The present results have showed potential application in fields of functional material and catalyst.

Ultra-Fine Treatment of SiC Powder and Its Effect on Microstructure and Properties of SiC Ceramic

The ultra-fine treatment of industrial SiC powder was carried out by fluidized bed opposed jet milling (QLM-100K), and the influences of grinding parameters on the ultra-fine treatment were studied. A better grinding result is achieved through a higher crushing pressure and a higher sorter frequency and the ultra-fine treated SiC powder possesses a smaller particle size, a narrower particle-size distribution, a higher specific surface area and reduced agglomeration. The effects of ultra-fine treatment on the compaction behaviors, sintering behaviors, properties and microstructure of SiC ceramics were investigated. The compact with ultra-fine treated powder has a higher density and a lower sintering temperature. The densification and mechanical properties of the ceramics can be ameliorated obviously and the microstructure defects of the ceramics decrease.