Papers by Author: Hong Li

Abstract: The glass-ceramics, whose coefficient of thermal expansion approximately matched to that of silicon, were studied to replace conventional heat-resistant glass as substrate material for anodic bonding. The basic glasses of the Li2O-Al2O3-SiO2 system with TiO2 and ZrO2 as nucleation agents were prepared by melting technology, and the temperatures of nucleation and crystallization were determined. The glass-ceramics were obtained by two-step heat-treatment method. The oriented crystallization of glasses in gradient temperature field was studied. The crystal phases and microstructures of glass- ceramics were analyzed. Effect of heat-treatment schedule on the coefficient of thermal expansion was discussed. The results showed that the most of the main crystal phases of the samples were β-spodumene. The coefficient of thermal expansion of sample was about 32.5×10-7/°C, which was approach to that of silicon.

Abstract: CaO-A12O3-SiO2 (CAS) system glass-ceramics were prepared by sintering with certain amount of yellow phosphorus slag. The effects of phosphorus and fluorine on the nucleation, crystallization and structure of CAS system glass-ceramics were investigated by differential thermal analysis, X-ray diffraction, scanning electron microscopy and other measuring methods. Glass-ceramics of CAS system with 42.32wt% yellow phosphorus slag were obtained by nucleating at 615°C for 1 hour and crystallizing at 926°C for 2 hours. The results showed that the introduction of phosphorus and fluorine promoted the nucleation and crystallization of glass-ceramics, lowering the crystallizing temperature. The main crystal phase of glass-ceramics was β-wollastonite. The density of the glass-ceramic was 2.695g/cm3.

Abstract: CaO-Al2O3-SiO2 (CAS) glass-ceramic is a novel material developed in recent years. It has a number of excellent properties, such as shining appearance, high strength, and good erosion resistance. So its practical prospect is wide. Many glass and ceramic scientists have studied this glass-ceramic, but there have been no publication made regarding corrosion mechanism. In order to choose the most suitable refractory materials for melting furnace for this glass-ceramic system, the corrosion and erosion mechanism must be investigated. The results can then be used to design the furnace and predict the life of the melting furnace. Also such investigation will reveal the extent of contamination of the final glass-ceramic product. According to the experiment that the glass liquid corrodes refractory materials in static condition, various effective material test method were used, especially Electron Probe Microanalysis (EPMA). Using EPMA, the chemical species, morphology, size and distribution of refractory materials corroded can be observed, so we know the microstructure of refractory materials prior to and after being corroded as well as the features of changing. In this paper, the authors present the features of refractory materials microstructure prior to and after being corroded by means of analyzing these pictures, which is very useful to provide the reliable theory to establish the mechanism that CAS glass-ceramic liquid corrodes the refractory materials.