玻璃的退火

用自熔融冷至制品,玻璃六个物理特性阶段的后四个阶段中的结构调整、调整终止和热应力演绎,从微观到宏观阐明了玻璃退火全过程的本质:"两个退火阶段和四种退火状态".由此得到了浮法玻璃退火窑设计的技术路线,指出了该项设计上的弊端,树立了新的设计理念.     

SOME EFFECTS OF CAREFULLY ANNEALING OPTICAL GLASS1

The apparent lack of optical homogeneity in good optical glass may be the result of small differences in temperature during annealing. That this can be eliminated to a large extent by careful furnace control has been demonstrated. Furthermore, this may be done without appreciable change in the average index of refraction if the “thermooptical” constants of the glass are predetermined.     

ELECTRIC ANNEALING OF GLASS*

The total and distribution heat requirements are discussed in general as well as the manner in which electric leers economically meet these requirements based on actual determinations and calculations.     

DESIGN OF A FURNACE FOR ANNEALING OPTICAL GLASS1

Design of a natural-gas furnace for annealing optical glass.—Most of the furnaces built for annealing regular glassware are unsuitable for optical glass due to irregularity and inequality of temperatures. Working drawings are given for a successful optical glass annealing furnace operated by natural gas. The design is novel in the placing of the flues and burners in such a manner as to supply the heat and remove it in a symmetrical manner, thus obtaining uniformity of temperature.     

AN APPARATUS FOR DETERMINING THE ANNEALING CONSTANTS OF GLASS1

An apparatus is described by means of which annealing data on glass may be rapidly and accurately obtained. Essentially, the apparatus consists of a mechanical means straining the glass, an optical means of measuring the stresses, and a means of heating the sample uniformly while making the measurement. The results are consistent and expressed in definite terms. The specimens for test may be quite small. The apparatus may be used for control purposes in place of measuring softening temperatures.     

VISCOSITY-TIME-TEMPERATURE RELATIONS IN GLASS AT ANNEALING TEMPERATURES*

Viscosity data published by the author in 1931 are discussed with reference to their limitations. New experiments on fiber elongation in a redesigned apparatus are described in which one of the glasses previously used is tested. The results show that the viscosity of a newly drawn fiber increases with time of heat treatment according to a definite law which may be explained on the basis of a change in the state of aggregation in the glass. A finite equilibrium viscosity is indicated at each temperature, this limit being approachable from either side depending on previous heat treatment of the sample. This is taken to indicate an equilibrium average size of aggregate for any temperature, the groups starting to break up again if the temperature is increased after a long treatment. The expression of Sheppard and Houck is used for estimating effective molecular or aggregate weights in equilibrium at various temperatures, an example being 112,000 at about 500°C. The variation of viscosity with time is at least one reason why glasses fail to conform to Adams' and Williamson's annealing equation at low temperatures.     

ANNEALING STRAINS IN GLASS AND THEIR DEGREE OF PERMANENCE*

A statistical comparison has been made of 13 sets of measurements of optical path difference, taken over a seven-year period, on 24 samples of the standardized disks distributed in 1938 to the manufacturers of glass containers. These data show that the original optical retardation of about 22.8 millimicrons has not changed by more than =1.3%, equivalent to =0.30 millimicron or =0.10° on the scale of the measuring instrument. Five tests were made in 1938, five in 1945, and three between. The standard deviation of the combined errors for each of the 13 averages of 24 measurements is =0.0338° and is composed of an accidental error of observation of =0.005° and an error of adjustment of the instrument of =0.0333°. The range of =1.3%, or =0.10°, beyond which the disks could not have changed over seven years, represents the 3-sigma probability limit of combined errors. While this possible change of =1.3% would be insignificant in relation to the utility of the standardized disks, it represents a possible experimental error too great to permit broad conclusions concerning the ultimate stability of birefringence in strained glass.     

浮法玻璃退火过程中玻璃带内的温度场和应力松弛

本文建立了浮法玻璃退火过程中玻璃带内温度场的数值计算与制图方法，并得出了玻璃带厚度方向温度分布随时间的变化关系。本文还做了玻璃应力松弛试验，结果表明，采用RD2-3型改进应力松弛试验机是可靠的。     

NATURE OF THE GLASS PHASE IN HEATED CLAY MATERIALS: II*

The glass phase in the bodies studied was more sensitive to variations in heat treatment than were the physical properties. Increased rates of heating caused less glass and mullite formation, less quartz corrosion, more pores and blebs, and increased heterogeneity of the glassy matrix. Microstructure and physical properties indicated an optimum heating rate between 50° and 90° per hour. Soaking increased the amount of glass, more so after slow than after rapid heating. Soaking after rapid heating did not reduce the number of blebs. Soaking too long and at too high temperatures made blebs more numerous. A minimum soaking time of one hour seemed desirable. The optimum heating rate and minimum soaking time governed the shortest heating schedule productive of the best microstructure and physical properties.     

STUDY OF TIME AND TEMPERATURE EFFECTS ON GLASS IN ANNEALING RANGE*

Samples of a melt of borosilicate glass have been treated by holding them for periods up to 500 hours at constant temperature. The equilibrium condition was attained to a very close approximation at several temperatures. This nearness of approach makes possible the comparison of various proposed equations relating the rate of change of physical properties to their equilibrium values. Refractive index was the characteristic used to indicate the rate of approach to equilibrium conditions. It is shown that the equations expressing dn/dt as first or second degree functions of (n_e-n) do not seem to fit the present data. The equation of Tool is then transformed to give equation (7) (of the text) for the rate of change of index. It is shown that this equation appears to represent adequately the rates of change of index derived from the present data and also those of previous investigators.     

热处理条件对硅酸盐玻璃中原位形成银纳米颗粒的影响

用离子交换结合热处理法制备银(Ag)纳米颗粒-玻璃复合材料.用透射电镜、高分辨透射电子显微镜、Ruthefford背散射谱和紫外-可见光吸收光谱研究了热处理条件对玻璃中原位形成Ag纳米颗粒的影响.结果显示:随着热处理温度升高,玻璃表面的Ag原子逐渐向玻璃内部扩散,其表面摩尔浓度逐渐降低.提高热处理温度和延长热处理时间都有利于提高玻璃中Ag纳米颗粒的体积分数.空气中,高温热处理高掺Ag量的白玻璃样品时发生二次成核,因此,Ag纳米颗粒尺寸呈双峰分布.Ag纳米颗粒尺寸的双峰分布导致其等离子体共振吸收峰出现双峰.在氢气气氛中,在250℃热处理2min,即可在玻璃中形成大量Ag纳米颗粒,颗粒尺寸小于空气中高温热处理样品的尺寸,从而引起表面等离子体共振吸收峰发生蓝移.     

窑后期浮法玻璃退火质量问题的技术研究

根据退火工艺控制的基本理论,结合国内某浮法玻璃生产线窑后期退火攻关实际状况,阐述了窑后期退火工况控制技术的关键及相应措施,以求对国内同行业的生产控制和技术水平的提高起到积极的作用.     

RELATION BETWEEN INELASTIC DEFORMABILITY AND THERMAL EXPANSION OF GLASS IN ITS ANNEALING RANGE*

In accordance with experience concerning the behavior of glass at temperatures within its annealing range, an equation is proposed which relates the various extraordinary heat effects to the inelastic deformability and to the degree of superheating or undercooling. By using this equation in connection with the thermal-expansion curves of a glass within its annealing range, certain constants that are related to the coefficient of viscosity and its changes with temperature and the degree of superheating or undercooling have been determined with reasonable results. Such results make it possible to estimate the inelastic deformability of a glass in its various conditions at all annealing temperatures and are therefore valuable in connection with problems that are encountered in the process of annealing glass. The apparent success achieved in applying the proposed equation to experimental data suggests that the concepts underlying this equation are fundamental and must be considered in any theory concerning the constitution of glass or that of any other extremely viscous liquid.     

BERYLLIUM GLASS1

Beryllium glass has been prepared for the first time, and some of its physical and optical properties have been determined. More than eighty different compositions have been melted and studied. Four series were taken from the clear glass area and examined for density, hardness, refractive index, and ultra-violet light transmission in comparison with magnesium and calcium glasses     

VARIATIONS OF REFRACTIVE INDEX OF GLASS WITH TIME AND TEMPERATURE IN ANNEALING REGION*

The refractive index of a rapidly cooled fiber of borosilicate glass was found to increase according to the equation, 1/(N₆–N) – 1/(N₆–N₀) =At, where t is time, N₆ is equilibrium index, and A is a constant at constant temperature. Index data were plotted according to this equation to determine, graphically, values of N₆ and A for several temperatures between 914° and 1060°F. Values of N₆ for temperatures from 1060° to 1180°F. were determined by prolonged heating of the glass at each 20° interval. The change of A with temperature was found to be well represented by the equation, log A=K/T+C, where T is the absolute temperature and K and C are constants.     

GLASS CONTAINERS1

For centuries glass bottles have been recognized as superior containers. At present over 4000 different sizes and shapes are being made and the industry is in a state of rapid extension. Glass containers possess the advantage of being sanitary and permitting the contents to be seen. Recently the laboratory of the Glass Container Association has tested 180 lots of beverage bottles. Some of the better types, or those approaching the champagne style, were found to withstand an end crushing pressure of from 8000 to 12000 pounds, a transverse pressure of from 800 to 1800 pounds, a hydrostatic pressure of from 400 to 1600 pounds, and an impact of a fifty-pound hammer falling from 2 to 6 feet. Similar tests are in progress on other types of containers and on the closures employed. Troubles due to alkalinity are of rare occurrence.     

COLLOIDS IN GLASS1

A discussion of the various elements and compounds found in a colloidal state in glass. Attention is called to the similarity of colloidal behavior in vitreous and aqueous media. Theories and experimental evidence are furnished to account for the formation and destruction of the colloidal state.