Papers by Author: Jin Shu Cheng

Abstract: This paper focus on choosing the optimum forming temperature, drawing speed and installing the appropriate apparatus to control the thickness and shrinkage in the process of drawing flexible glass. The results showed that when the temperature of the glass was raised from 990K to 1100K, the thickness of the glass increased at a fixed drawing speed. As the drawing speed of the glass was increased from 6m/h to 21m/h, the thickness of the glass decreased while the shrinkage of the glass increased at a fixed drawing temperature. The optimum forming temperature ranged from 1025 to 1050K and the optimum drawing speed was 21m/h.At the same time, in order to get a suitable size of flexible glass, the pull-edge machines and cooling devices were installed in the drawing apparatus to control the shrinkage of glass.

Abstract: The study was carried out on the burning test-bed which was controlled by Programmable Logic Controller (PLC) model and diesel was used as the fuel. The thermodynamic characteristic of oxygen-enhanced combustion, including fuel consumption, flue gas volume, flue gas components’ volume concentration, theoretical flame temperature, flame emissivity, energy efficiency and thermal efficiency, etc, were analyzed. The results showed that: with oxygen concentration was increased from 21% to 30%, fuel consumption was decreased by 40.6% and flue gas volume was decreased by 57.5%. Additionally, higher oxygen concentration leaded to higher theoretical temperature and stronger flame blackness because of the decreasing of N2 volume in supporting air. What’s more, the decreasing of energy brought away by flue gas and the thermal efficiency were both increased with the increasing of oxygen concentration.

Abstract: The non-isothermal crystallization kinetics of the MgO–Al2O3–SiO2 (MAS) glasses were analyzed with the Kissinger equation and the Augis-Bennett equation by differential scanning calorimeter (DSC) and X-ray diffraction (XRD). The results showed that two crystal phases of spinel (MgAl2O4) and SiO2 were generated sequentially in the heat treatment process. When the spinel was the only crystal phase, the MAS glass-ceramic was transparent. For glass A (containing one type alkali metal Na2O), the corresponding activation energy was Ep1(A)=325.27kJ/mol, Ep2(A)=364.99kJ/mol; for glass B (containing Na2O and K2O) , the activation energy is Ep1(B)=233.79kJ/mol, Ep2(B)=273.85kJ /mol. The average crystallization index for spinel crystal phase was nA1=1.99, nB1=2.58, By adding K+, which suggested that the spinel crystal phase precipitation have the trend to change from two-dimensional pattern to bulk crystallization.

Abstract: Sintering glass-ceramics, a new type material for architectural decoration, belong to CaO-Al₂O₃-SiO₂ system (CAS) without nucleation agent. Combined by Differential thermal analysis (DTA), X-ray diffraction (XRD), Scanning electron microscopy (SEM) and Transmission electron microscope (TEM), phase evolutionary process of CaO-Al₂O₃-SiO₂ system glass and glass-ceramic was investigated. According the relation between heat treatment schedule and microstructure, the glass system has a very wide temperature range of crystallization. The crystalline phase is β-CaSiO₃ (β-wollastonite) and there is no other crystalline phases precipitated in these glass-ceramics. The influences of various heat treatment systems on the structure and properties of the glass-ceramics were investigated simultaneously. The optimal heat treatment schedule, microstructure and bending strength of the CAS glass ceramic were gained.

Abstract: The polar glass-ceramics of 2.0SrO-1.0TiO2-2.9SiO2 system were prepared by the process of recrystallization with additional applied isothermal and electric field. The results showed that the glass-ceramics piezoelectric constant d33 was 12×10-12 C/N. The study of its oriented crystallization by SEM and XRD indicated that Sr2TiSi2O8 crystal performed oriented growth, which was perpendicular to the glass surface and made it be orientally crystallized with the assisted the isothermal and electric field. The further experimental results showed that the additional electric field reduced the crystallization activation energy, which provided a force for the isothermal orientating crystallization process.

Abstract: Much phosphorus slag which is produced every year, not only brings about the resource waste, but also results in the pollution of the environment. In the paper, phosphorus slag was added into the glass-ceramics of CaO-Al2O3-SiO2 system. Through increasing the CaO content of CaO-Al2O3-SiO2 system glass-ceramics and keeping constant content of the phosphorus slag, the phosphorus slag glass-ceramics were obtained. The optimum compositions of CaO-Al2O3-SiO2 system phosphorus slag glass-ceramics was obtained through careful analysis based on X-ray diffraction (XRD), scanning electron microscopy (SEM) and other measuring methods. The results showed that with increasing of CaO content, the leveling temperature, the crystal content and the densities of samples were gradually increasing, however, the leveling temperature range was gradually narrowing. When the content of phosphorus slag was 30wt%, the addition of 17wt%CaO was more reasonable. The main phase of phosphorus slag glass-ceramic was β-wollastonite. The leveling temperature range of glass-ceramic was 1130-1140°C and the holding time was 2 hours.

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.