Development of SiC ultra light mirror for large space telescope and for extremely huge ground-based telescope

Ebizuka, Noboru; Dai, Yutang; Eto, Hiroaki; Lin, Weimin; Ebisuzaki, Toshikazu; Omori, Hitoshi; Handa, Thoshikazu; Takami, Hideki; Takahashi, Yoshiyuki

doi:10.1117/12.457408

Cited by 13 publications

(5 citation statements)

References 3 publications

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“…This method is more available than the traditional method. But the electrolytic grinding fluid ratio and other factors will be further studied [30] . ELID grinding of SiC mirror has reach surface roughness 0.8-1.5nm rms about domestic raw materials, surface accuracy is almost 0.016λ rms, but it is difficult to have high lightweight rates of SiC mirror by this method.…”

Section: Be Mirror Processing Technologymentioning

confidence: 99%

Study of Space Big Aperture New Materials Mirror and its Technology

Gai

Niu

Fang

2011

AMR

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In order to keep step with new materials mirrors and its technology of developed of international space optics system, and promote research level of national new material mirror, the optimization methods of new mirror materials were introduced, and the application of new material mirrors was elaborated. The researching technologies and methods of new materials mirror substrate were recommended. The researching technologies and methods of new materials mirror were narrated. And at same time, the new materials mirror technology and directions of our country were pointed out.

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Section: Be Mirror Processing Technologymentioning

confidence: 99%

Study of Space Big Aperture New Materials Mirror and its Technology

Gai

Niu

Fang

2011

AMR

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“…The silicon carbide (SiC) material is used for the mirrors of space telescopes and molds for glass optics manufacturing, due to the superb characteristics of high hardness, chemical inertness, and its low specific gravity [1][2][3]. As a result of its high hardness, it is not easily damaged by external scratches and has high thermal conductivity with low thermal expansion; therefore, it is the most suitable material for space telescopes that have to withstand extreme environments that deform or distort the optical component by high range of temperature change [4][5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Silicon Carbide Wafer Machining by Using a Single Filament Plasma at Atmospheric Pressure

et al. 2021

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SiC wafers were etched using a filament plasma of He:NF3:O2 (helium:nitrogen trifluoride:oxygen) mixed gas at atmospheric pressure. When 0.5–2 sccm of NF3 was mixed to 2 slm of He filament plasma, the etch depth and etch rate increased, but there was little change in the etch width as the NF3 mixing amount increased. The increment of the NF3 mixing also suppressed the surface roughening of plasma etching. The addition of O2 to the He-NF3 filament plasma slightly increased the SiC wafer etch rate. When the NF3 mixing amount was 2 sccm, the roughness of the etched surface increased sharply by O2 addition. On the contrary, the NF3 mixing amount was 1 sccm; the addition of O2 reduced the roughness more than that of the pristine. The roughness of the pristine SiC wafer specimens is in the range of Ra 0.7–0.8 nm. After 30 min of etching on a 6 mm by 6 mm square area, the roughness of the etched surface reduced to Ra 0.587 nm, while the etch rate was 2.74 μm/h with a He:NF3:O2 of 2:1:3 (slm:sccm:sccm) filament plasma and 3 mm/s speed of raster scan etch of the optimized roughening suppression etching recipe.

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“…Reaction-bonded silicon carbide (RB-SiC) is a good candidate material for large space optical mirrors due to their high strength, high thermal conductivity, enhanced radiation stability, and thermal shock resistance characteristics [ 1 , 2 , 3 ]. To date, grinding with superhard fine abrasives is the primary method used in achieving the desired tolerances and surface integrity for engineering ceramic machining [ 4 , 5 ].…”

Section: Introductionmentioning

confidence: 99%

A New Grinding Force Model for Micro Grinding RB-SiC Ceramic with Grinding Wheel Topography as an Input

Zhang

Luo

et al. 2018

Micromachines

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The ability to predict the grinding force for hard and brittle materials is important to optimize and control the grinding process. However, it is a difficult task to establish a comprehensive grinding force model that takes into account the brittle fracture, grinding conditions, and random distribution of the grinding wheel topography. Therefore, this study developed a new grinding force model for micro-grinding of reaction-bonded silicon carbide (RB-SiC) ceramics. First, the grinding force components and grinding trajectory were analysed based on the critical depth of rubbing, ploughing, and brittle fracture. Afterwards, the corresponding individual grain force were established and the total grinding force was derived through incorporating the single grain force with dynamic cutting grains. Finally, a series of calibration and validation experiments were conducted to obtain the empirical coefficient and verify the accuracy of the model. It was found that ploughing and fracture were the dominate removal modes, which illustrate that the force components decomposed are correct. Furthermore, the values predicted according to the proposed model are consistent with the experimental data, with the average deviation of 6.793% and 8.926% for the normal and tangential force, respectively. This suggests that the proposed model is acceptable and can be used to simulate the grinding force for RB-SiC ceramics in practice.

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Development of SiC ultra light mirror for large space telescope and for extremely huge ground-based telescope

Cited by 13 publications

References 3 publications

Study of Space Big Aperture New Materials Mirror and its Technology

Study of Space Big Aperture New Materials Mirror and its Technology

Silicon Carbide Wafer Machining by Using a Single Filament Plasma at Atmospheric Pressure

A New Grinding Force Model for Micro Grinding RB-SiC Ceramic with Grinding Wheel Topography as an Input

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