熔融石英的石英陶瓷研究

研究了用熔融石英代替石英玻璃生产石英陶瓷的基本工艺。分析了注浆和烧结的工艺原理,工艺参数与材料性能之间的关系。用熔融石英也能制备性能良好的石英陶瓷材料。     

熔融石英砖的蚀变过程及特点

由于熔融石英砖的热膨胀系数小,它在玻璃熔窑上被作为热修补材料使用,从而也存在和其它耐火材料一样被侵蚀,引起蚀变,并在玻璃液中产生疵点的现象.本文从几个典型的侵蚀样品的岩相分析中,试图揭示其变化过程及特点.     

提高熔融石英陶瓷力学性能的方法

介绍了提高熔融石英陶瓷力学性能的4种方法，即加入纤维、晶须、第二相颗粒及表面压应力增强。     

氮化硅对注凝成型熔融石英陶瓷性能影响的研究

以丙烯酰胺(AM)为有机单体,N,N'-亚甲基丙稀酰胺(MBAM)为交联剂,过硫酸铵(APS)为引发剂,pH=3.5,温度为1190 ℃保温5 h的条件下,采用注凝成型方法制备熔融石英陶瓷;以氮化硅为添加剂,通过XRD、SEM等分析不同氮化硅添加量对熔融石英陶瓷的影响,结果表明,氮化硅促进石英陶瓷的烧结,不会导致方石英出现;试样常温抗折强度、体积密度随氮化硅添加量的增加而增大,而显气孔率随氮化硅添加量的增加而减小.当氮化硅添加量为2%时,试样常温抗折强度为37.13 MPa,体积密度为1.96 g/cm3 ,显气孔率为10%.     

熔融石英耐火材料

阐述了熔融石英耐火材料的主要性能与应用领域。     

熔融石英烧成窑具制品的研究

采用新的结合系统对熔融石英烧成窑具材料进行了研究,结果表明,莫来石结合的熔融石英窑具材料具有优良的性能,从显微结构看,其表面析出的方石英数量很少。     

熔融石英—堇青石窑具的研究

根据材料总体热膨胀系上，复相组成膨胀系数适度失配的原则，采用半干法，开发研制了热稳定性的熔融石英－堇青石窑具。分析了影响该材料性能的机理。     

熔融石英陶瓷的开发及应用

概述了熔融石英陶瓷的制造工艺及性能特点,对比分析了其国内外发展概况,介绍了石英陶瓷辊,闸板砖,空心辊,旋转等几种高档熔融石英陶瓷制品的开发进展及应用情况。     

球形硅微粉的微观结构研究

文章采用XRD、SEM研究了球型硅微粉的晶体结构和微观结构。XRD测试晶体结构,发现高温熔融喷射法制备的球型硅微粉里面有晶态石英存在;SEM分析微观结构发现高温熔融喷射法制备的部分球型硅微粉颗粒内部有孔洞存在。通过对晶体结构和微观结构进行分析,找到了高温熔融喷射法生产的球型硅微粉内结晶态存在的原因。     

Effect of Cristobalite on the Strength of Sintered Fused Silica Above and Below the Cristobalite Transformation

Porous fused silica ceramics which had been partially devitrified to cristobalite were stronger at 350°C in the beta‐cristobalite stability range, but weaker at 25°C after the transformation to alpha‐cristobalite. The tensile strength distribution for different cristobalite fractions are compared for three types of specimens. These were beta‐cristobalite samples which had never been transformed to alpha‐cristobalite; room‐temperature samples with alpha‐cristobalite; and samples at 350°C which had retransformed to beta‐cristobalite after prior transformation to alpha‐cristobalite. The alpha‐cristobalite samples displayed 50%–75% the strength of samples tested on beta and the difference in strength was dependent on cristobalite content. Specimens retransformed to beta‐cristobalite had strength similar to virgin specimens. Microcracking associated with the transformation to alpha‐cristobalite contributes to the strength changes but cannot fully explain the impact of the beta–alpha transformation on strength.     

Kinetics of Cristobalite Formation in Sintered Silica

The kinetics of the cristobalite transformation are reported for sintered silica glass from 1200°C to 1650°C and plotted as a time–temperature–transformation diagram. The 1200°C–1350°C transformation data were fit to the Johnson–Mehl–Avrami–Kolmogorov expression with an time exponent of 3.0 ± 0.6 and an apparent activation energy of 555 ± 24 kJ/mol for the kinetic constant. The temperature of maximum transformation rate was found to fall between 1500°C and 1600°C. Seeding amorphous silica powder with cristobalite resulted in accelerated transformation kinetics. Silica glass powder containing residual quartz had faster transformation kinetics than fully amorphous powder seeded with cristobalite.     

Pseudopotential Periodic Hartree-Fock Study of the Cristobalite Phases of Silica and Germanium Dioxide

Periodic pseudopotential Hartree–Fock calculations have been performed on the cristobalite strucure of silica and germanium dioxide in order to investigate the topology of the ground-state Born–Oppenheimer energy surface. For both oxides the averaged X–O bond lengths, the two unequivalent O–X–O bond angles, and the tilt angle have been optimized. The tilt angle, which measures the rotation of the XO₄ tetrahedra around their local C ₂ axes, is directly related to the O–X–O bond angle and connects the low-temperature phase twin structures; its zero corresponds to the ideal β-phase. For SiO₂ the calculated values of these coordinates agree within 1% with 10 K experimental data whereas for GeO₂ the agreement between calculation and experiment is much less satisfactory. It is shown that the tilt angle is the most important structural parameter. The structure of β-cristobalite is rationalized on the basis of the energy dependence upon tilt angle and the absence of β-structure in GeO₂ is explained. The one-electron properties, i.e., band structure and density of states, have been calculated and are compared with the results of previous calculations carried out by other methods. As expected in Hartree-Fock calculations, the band gap is overestimated. The analysis of the calculated electron density and of density of states projected onto basis orbitals indicates that these oxides are mostly ionic. It is also shown that the GeO bond is more covalent than the SiO one, which explains the different behavior of these two oxides.     

石英陶瓷注凝成型影响因素的研究

介绍了熔融石英陶瓷的注凝成型机理及其工艺过程,分析讨论了影响熔融石英陶瓷注凝成型的主要因素,通过研究确定了合理的制备工艺参数.     

熔融石英陶瓷的凝胶注模成型研究

本文介绍了熔融石英陶瓷的凝胶注模成型,所制备的浓悬浮体的固相体积含量可达80％,烧后密度可达理论密度的87％。     

凝胶注模成型厚实熔融石英陶瓷研究

介绍了凝胶注模成型厚实熔融石英陶瓷工艺所制备的浓悬浮体的质量分数可达90％，烧后产品密度可达理论密度的87％。     

凝胶法制备熔石英纳米复合陶瓷工艺及性能的研究

对凝胶法制备熔石英纳米复合陶瓷的工艺进行了探讨,并对不同工艺参数下的材料性能进行了分析和对比,讨论了影响材料性能的主要因素,寻求其最佳工艺参数.研究结果表明,用凝胶法可以使纳米相粒子均匀分散于陶瓷基体中,并能方便快速制备熔石英纳米复合陶瓷,纳米相引入后明显改善了材料的烧结性能,增加了材料的密度和强度.