Manufacturing Technology of Space Optical Materials

2013 ◽  
Vol 785-786 ◽  
pp. 1018-1021
Author(s):  
Ya Chen
Keyword(s):  
Silicon Carbide ◽  
Low Temperature ◽  
Glass Ceramics ◽  
Performance Comparison ◽  
Manufacturing Technology ◽  
Surface Shape ◽  
Element Analysis ◽  
Shape Precision ◽  
Lightweight Structure ◽  
Materials Used

In this paper, the performance comparison between glass ceramics (Zerodur) and silicon carbide (SiC) which are two kinds of common materials used for space optical reflector is carried out, and several lightweight structure forms are analyzed. The oval plane reflector is applied in ultra-low temperature environment of space, take this kind of reflector as an example, its lightweight structure is optimized by CAD, then through finite element analysis, deformation of the planar lightweight mirror is 0.014λ (rms) in gravity condition, and deformation is 0.002λ (rms) in ultra-low temperature of-150 degrees environment. The actual lightweight processing is controled by the CNC system in a graphical way, and using chemical method to eliminate the stress and micro crack generated during processing, its final surface shape precision reaches 0.022λ (rms). Finally, this paper introduces the manufacture method of novel silicon carbide (SiC), and analyzes the current situation and development trends of the spatial lightweight reflector manufacturing technology.

Manufacture Technology for Large Lightweight Optical Materials

2014 ◽  
Vol 941-944 ◽  
pp. 623-626
Author(s):  
Ya Chen
Keyword(s):  
Silicon Carbide ◽  
Low Temperature ◽  
Optical Materials ◽  
Glass Ceramics ◽  
Performance Comparison ◽  
Surface Shape ◽  
Element Analysis ◽  
Shape Precision ◽  
Lightweight Structure ◽  
Materials Used

In this paper, the performance comparison between glass ceramics (Zerodur) and silicon carbide (SiC) which are two kinds of common materials used for space optical reflector is carried out, and several lightweight structure forms are analyzed. The oval plane reflector is applied in ultra-low temperature environment of space, take this kind of reflector as an example, its lightweight structure is optimized by CAD, then through finite element analysis, deformation of the planar lightweight mirror is 0.014λ (rms) in gravity condition, and deformation is 0.002λ (rms) in ultra-low temperature of-150 degrees environment. The actual lightweight processing is controled by the CNC system in a graphical way, and using chemical method to eliminate the stress and micro crack generated during processing, its final surface shape precision reaches 0.022λ (rms). Finally, this paper introduces the manufacture method of novel silicon carbide (SiC), and analyzes the current situation and development trends of the spatial lightweight reflector manufacturing technology.

Study on Low Temperature Sintering Behaviour of CaO-B2O3-SiO2 Glass Ceramics

2010 ◽  
Vol 150-151 ◽  
pp. 350-353
Author(s):  
Peng Fei Wei ◽  
Hong Qing Zhou ◽  
Hai Kui Zhu ◽  
Bin Dai ◽  
Jie Wang
Keyword(s):  
Low Temperature ◽  
Glass Ceramics ◽  
Sintered Sample ◽  
Sintered Glass ◽  
Powder Characteristics ◽  
Sintering Properties ◽  
Median Particle ◽  
Materials Used ◽  
Sintering Behaviour ◽  
The Relationship

CaO-B2O3-SiO2 glass ceramics were prepared by powders of different particle sizes. The relationship between CBS powder characteristics and structures was studied by XRD and SEM, and the effect of powder characteristics on sintering properties, dielectric properties at 10GHz, thermal properties (CTE) were investigated to obtain low-temperature sintered glass ceramics. The results showed that the median particle size of glass powders reduced, sintered temperature and apparent porosity decreased. But at the same time, bulk density and thermal expansivity increased. The sample with the powders of D50=2.34μm could be sintered at 850 with the density about 2.615g•cm-3 and the water absorption about 0.16%. Having a dielectric constant of 6.16 and a dielectric loss of 1.9×10-3 at 9.98GHz, the sintered sample could satisfy the requirements of the substrate materials used in LTCC in some fields.

Energy saving technology for sintering of black bricks from high-siliceous clay

MRS Advances ◽  
2020 ◽  
Vol 5 (61) ◽  
pp. 3123-3131
Author(s):  
Mario Flores Nicolas ◽  
Marina Vlasova ◽  
Pedro Antonio Márquez Aguilar ◽  
Mykola Kakazey ◽  
Marcos Mauricio Chávez Cano ◽  
...  
Keyword(s):  
Low Temperature ◽  
Oxygen Deficiency ◽  
Glass Ceramics ◽  
Total Content ◽  
Ceramic Materials ◽  
Ternary Mixtures ◽  
High Porosity ◽  
Reducing Conditions ◽  
Binary And Ternary Mixtures ◽  
Dark Color

AbstractThe low-temperature synthesis of bricks prepared from high-siliceous clays by the method of plastic molding of blanks was used. For the preparation of brick blanks, binary and ternary mixtures of high-siliceous clays, black sand, and bottle glass cullet were used. Gray-black low-porosity and high-porosity ceramics was obtained by sintering under conditions of oxygen deficiency. It has been established that to initiate plastic in mixtures containing high-siliceous clay, it is necessary to add montmorillonite/bentonite additives, carry out low-temperature sintering, and introduce low-melting glass additives with a melting point ranging from 750 to 800 °C. The performed investigations have shown that the sintering of mixtures with a total content of iron oxide of about 5 wt% under reducing conditions at Tsint. = 800°C for 8 h leads to the formation of glass ceramics consisting of quartz, feldspars, and a phase. The main sources of the appearance of a dark color is the formation of [Fe3+O4]4- and [Fe3+O6]9- anions in the composition of the glass phase and feldspars. By changing the contents of clay, sand, and glass in sintering, it is possible to obtain two types of ceramic materials: (a) in the form of building bricks and (b) in the form of porous fillers.

scholarly journals Investigation of Energy-Absorbing Properties of a Bio-Inspired Structure

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 881
Author(s):  
Adrian Dubicki ◽  
Izabela Zglobicka ◽  
Krzysztof J. Kurzydłowski
Keyword(s):  
Absorption Capacity ◽  
Compression Tests ◽  
Element Analysis ◽  
Lightweight Structures ◽  
New Energy ◽  
Absorbing Material ◽  
Lightweight Structure ◽  
3D Printed ◽  
Deformation Force ◽  
Energy Absorbing

Numerous engineering applications require lightweight structures with excellent absorption capacity. The problem of obtaining such structures may be solved by nature and especially biological structures with such properties. The paper concerns an attempt to develop a new energy-absorbing material using a biomimetic approach. The lightweight structure investigated here is mimicking geometry of diatom shells, which are known to be optimized by nature in terms of the resistance to mechanical loading. The structures mimicking frustule of diatoms, retaining the similarity with the natural shell, were 3D printed and subjected to compression tests. As required, the bio-inspired structure deformed continuously with the increase in deformation force. Finite element analysis (FEA) was carried out to gain insight into the mechanism of damage of the samples mimicking diatoms shells. The experimental results showed a good agreement with the numerical results. The results are discussed in the context of further investigations which need to be conducted as well as possible applications in the energy absorbing structures.

scholarly journals Demonstration of a Robust All-Silicon-Carbide Intracortical Neural Interface

Micromachines ◽  
2018 ◽  
Vol 9 (8) ◽  
pp. 412 ◽  
Author(s):  
Evans Bernardin ◽  
Christopher Frewin ◽  
Richard Everly ◽  
Jawad Ul Hassan ◽  
Stephen Saddow
Keyword(s):  
Silicon Carbide ◽  
High Performance ◽  
Electrical Characterization ◽  
Electrode Impedance ◽  
Voltage Range ◽  
Promising Solution ◽  
Multiple Materials ◽  
Diode Behavior ◽  
Materials Used ◽  
P Type

Intracortical neural interfaces (INI) have made impressive progress in recent years but still display questionable long-term reliability. Here, we report on the development and characterization of highly resilient monolithic silicon carbide (SiC) neural devices. SiC is a physically robust, biocompatible, and chemically inert semiconductor. The device support was micromachined from p-type SiC with conductors created from n-type SiC, simultaneously providing electrical isolation through the resulting p-n junction. Electrodes possessed geometric surface area (GSA) varying from 496 to 500 K μm2. Electrical characterization showed high-performance p-n diode behavior, with typical turn-on voltages of ~2.3 V and reverse bias leakage below 1 nArms. Current leakage between adjacent electrodes was ~7.5 nArms over a voltage range of −50 V to 50 V. The devices interacted electrochemically with a purely capacitive relationship at frequencies less than 10 kHz. Electrode impedance ranged from 675 ± 130 kΩ (GSA = 496 µm2) to 46.5 ± 4.80 kΩ (GSA = 500 K µm2). Since the all-SiC devices rely on the integration of only robust and highly compatible SiC material, they offer a promising solution to probe delamination and biological rejection associated with the use of multiple materials used in many current INI devices.

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