Papers by Keyword: Quartz Glass

Abstract: Quartz glass is a typical hard and brittle material. During the manufacturing process of quartz glass components, ultra-precision grinding is widely used due to its high throughput and good dimensional accuracies. However, grinding will unavoidably induce large surface and subsurface damage. In this study, the surface and subsurface damage characteristics of quartz glass substrates ground by diamond wheels with different grit sizes were investigated in terms of surface roughness, surface topography, subsurface microcrack characteristic, and subsurface damage depth. Discussion was also provided to explore corresponding reasons of surface and subsurface damage induced by diamond grinding wheels with different grit sizes of #1500 and #2000. The experiment results showed that the surface roughness, surface damage, and subsurface damage depth induced by #2000 quartz glass was ground by #1500 diamond grinding wheel, and in ductile mode when ground by #2000 diamond grinding wheel.

Abstract: The methods for evaluating the quality of the protective coating to the size etching of quartz glass with hydrofluoric acid were proposed. Molybdenum coating is generated with the installation NIKA 2012 TN by magnetron sputtering. Quartz glass with a roughness of Ra less than 1 nm was used. Discontinuity of coating was determined by the method of electron microscopy and energy dispersive analysis. Mathematical modeling of the hydrofluoric acid diffusion process performend via the molybdenum film was implemented. X-ray analysis of the coating was carried out to determine the residual internal stresses. We concluded that the studied phenomena affect the quality of the glass surface after etching.

Abstract: Sheet steel enamels with mill addition of quartz glass were manufactured successfully in accordance with the ordinary enamel manufacturing technology. The effect of mill addition of quartz glass on thermal shock resistance and acid resistance of enamels was analyzed through XRD and SEM etc. The results show that the thermal shock of the enamel can be increased greatly by mill addition of quartz glass, and there is the rational range of mill addition of quartz glass in order for the enamel to achieve both the superior acid resistance and the excellent thermal shock.

Abstract: Optical homogeneity of the fused silica directly affects the wave-front quality of the optical system. Furthermore, three-dimensional optical homogeneity is required in order to produce high-precision prisms, because of its special optical demand. However, the three-dimensional optical homogeneity of fused silica is poor owing to the periodically grow laws based on vertical CVD technical in the process of ingots production. One circular and one square sample were prepared to measuring the three-dimensional optical homogeneity, founding that the vertical direction had worse optical homogeneity result compared to the horizontal direction. The constituents of the sample were tested and analyzed to found the inhomogeneity reason. The method was proposed to improve the three-dimensional optical homogeneity.

Abstract: Recently, diamonds have been utilized gradually for sliding parts and wear-resistant parts because of their excellent properties. The shape of diamond applied to these parts is not only plane but also arc-shaped inner surface. Therefore, development of diamond polishing technology is required. In this study, ultraviolet assisted polishing was thought to develop to polish polycrystalline diamond (PCD) on arc-shaped inner surface. The authors investigated effect of ultraviolet radiation on polishing efficiency and surface roughness. As a result, the surface roughness Ra of PCD showed less than 15 nanometers. In addition, polishing efficiency was improved about 30 percent due to ultraviolet assisted polishing.

Abstract: Optical homogeneity of the optical materials directly affects the wavefront quality of the refractive optical system. There are some difficulties of testing large caliber optical materials, four-step method of Fizeau interferometry is a convenient and accurate method for measuring optical homogeneity. The article used the four-step method test the same quartz glass sample in a cavity with different precision and found that the optical homogeneity test results have a larger gap. While this article compared the effect of the fixed cavity surface shape and the changing cavity surface shape on 300 mm diameter quartz glass optical homogeneity test and analyzed the effect of different positions of fixed cavity distortion on optical homogeneity testing.

Abstract: Synthetic quartz glass is an excellent transmittance material in ultraviolet (UV), visible and near-infrared bands. Homogenization process to synthetic quartz glass optical elements is done in order to make the composition and structure more uniform. The homogenization temperature is above 1800°C. After high-temperature homogenization, the UV transmittance of quartz glass appears a certain extent of decline in the edge partition., After high temperature homogenization process, it is found that the closer the layer to the graphite vessel, the stronger influence on UV transmittance will be. This conclusion is made by comparing the UV transmission of the quartz glass in different layers. Furthermore, the factors affecting the UV transmittance is also analyzed in this article.

Abstract: The surface morphology of quartz glass etched in HF acid is influenced by many factors, such as the quality of polishing, types of the quartz glasses, metal ion in HF acid, etc. This paper conducted an analysis on these factors and tried to make improvements. Meanwhile, this experiment approved of the model of both destructive layer and the varying of closed micro-cracks in the process of etching. Besides, the changing law of both ditch-like and pit-like flaws was investigated in this experiment, and conclusions could be drawn as follows: at the concave curvature, the bigger the radius of curvature is, the faster the etching will be; The etching rate with protruding curvature is higher than that of concave curvature; The etching rate with concave curvature is lower than that on the plane surface.

Abstract: Optical homogeneity is an important measurement of the optical materials, directly affects wavefront quality of the refractive optical system, changes the system wavefront aberration. As the traditional direct measurement method requires high precision surface shape machining for optical material (PV value < 0.1λ), it was gradually replaced by the method of Fizeau interferometer four step, which requires lower surface shape. This article used 600mm diameter Fizeau interferometer, a four step method tested the optical homogeneity of the same 500 mm diameter fused quartz material with a front surface shape respectively 3.719 λ and 0.427 λ (λ = 632.8nm). Comparison of the test results showed that the PV difference of optical homogeneity between the two was only 0.036 λ, △n inaccuracy was 10-7, and the homogeneity morphology matched exactly. To further analyze the factors affecting the optical homogeneity, the front surface shape of the other sample was sliced ​​in a predetermined direction. This artical analyzed the effect of morphology upon the slicing line on optical homogeneity. The conclusion was that the direct affecting factor on optical homogeneity was the slope of surface morphology, rather than the overall PV value.

Abstract: High speed sawing is an advanced machining technique for sawing of brittle materials with good component quality and high productivity. In the paper, sawing experiments were carried out to investigate the characteristics of sawing forces by altering many processing parameters in high speed sawing of quartz glass with a diamond blade. The sawing forces and force ratio were analyzed. The conclusions present that in the fixed material removal rate, the increasing of periphery speed can help to lower sawing forces and force ratio; sawing forces increase with material removal rate; in the high speed sawing, the effect of material removal rate on sawing forces is smaller than the one in the low speed.