An Ion Thruster Accelerating Electrode Made of Carbon-Carbon Composite Material

Ахметжанов, Р. В.; Balashov, V. V.; Bogachev, Ye. A.; Yelakov, A. B.; Kashirin, D. A.; Svotina, V. V.; Spivak, Oleksandr; Cherkasova, M.

doi:10.1134/s0040601518130025

Cited by 6 publications

(4 citation statements)

References 5 publications

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“…Usually, the grid materials should have the properties of high temperature resistance, sputter resistance, good thermal conductivity and for the protection of the ion thruster electric breakdown, the grid materials should have the capability of withstand high voltage. At present, molybdenum and C/C materials are the mostly used grid materials [80], [81], among which molybdenum can withstand higher voltage than C/C composites.…”

Section: A Mitigation Technologies Of Electric Breakdown For the Ion ...mentioning

confidence: 99%

“…However, it would limit the performance of ion thruster. The high grade of surface finish of grids and electrodes would also reduce the surface sputtering and erosion from surface burrs [62], [81]. From manufacturing to launch, the electrodes of the ion thruster would adsorb ambient gas particles, and the ion sputtering deposits would crack or warp due to thermal expansion and contraction.…”

Section: Control and Protection Technologies Of Electric Breakdown In...mentioning

confidence: 99%

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Ion Electric Propulsion System Electric Breakdown Problems: Causes, Impacts and Protection Strategies

Peng,

Li,

Song

et al. 2023

IEEE Access

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Ion electric propulsion systems have been widely used in satellite station keeping, attitude control, and orbit transfer due to their advantages of high specific impulse, good flexibility, and high reliability. The electric breakdown might happen at grids or across isolators due to the disturbing effects of the power source or environment. The electric breakdown can induce spurious effects in the power processing unit (PPU) circuit from the return currents and voltage drops, which could be several orders of magnitude higher than the impulses at normal working conditions. When the electric breakdown happens, it might result in serious electromagnetic interference and damage to the electric and electronic equipment in the spacecraft. This paper provides a comprehensive summary of the various factors that can cause electric breakdown in an ion electric propulsion system, such as environmental factors, manufacturing considerations, and operational conditions of the thruster. Furthermore, a comprehensive analysis of the impact of electric breakdown on the ion thruster, electric propulsion system, and spacecraft mission is explored. The effectiveness of different grounding configurations in safeguarding against ion thruster electric breakdown has also been evaluated. Based on the analysis and discussion, the control and protection strategies are proposed for the ion electric propulsion system electric breakdown problems.

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Section: A Mitigation Technologies Of Electric Breakdown For the Ion ...mentioning

confidence: 99%

Section: Control and Protection Technologies Of Electric Breakdown In...mentioning

confidence: 99%

Ion Electric Propulsion System Electric Breakdown Problems: Causes, Impacts and Protection Strategies

Peng,

Li,

Song

et al. 2023

IEEE Access

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“…The method used to build the reinforcing carbon preform was found to provide self-bonding (as inherited after pyrolysis) of the filaments. The new quality of the carbon preforms made it possible both to provide an effective substitute for the molybdenum electrodes used for ion thruster accelerating electrodes [3] and to find more effective methods to CVI them with the silicon carbide matrix [4].…”

Section: Introductionmentioning

confidence: 99%

Organomorphic Silicon Carbide Reinforcing Preform Formation Mechanism

Bogachev¹

2023

J. Compos. Sci.

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Development of the organomorphic ceramic-matrix composites (CMCs), where the reinforcing preform is built using polymer fibers subject essentially to hot pressing, was motivated by a desire to obtain much higher structural uniformity as well as to reduce the number of the process steps involved in the production of CMCs. This paper addresses the peculiarities of the organomorphic silicon carbide preform formation process. Using X-ray phase analysis, tomography, mass and IR spectroscopy, and thermomechanical and X-ray microanalysis, both the properties of the initial fibers of polycarbosilane (PCS)—the silicon carbide fiber precursor—and their transformation in the preform while heated to 1250 °C under constant pressing at 10–100 kPa were studied. Analysis of the data obtained showed the organomorphic SiC preform relative density at a level of 0.3–0.4 to be ensured by self-bonding of the silicon carbide preform, resulting from the fact that during the low-temperature part of pyrolysis, easily polymerizing substances are released leaving a high coke residue, thus cementing the preform. Another possible factor of SiC framework self-bonding is the destruction of the polymer fibers during pyrolysis of various PCS preforms differing in their methylsilane composition (for example, dimethylsilane), where deposition of silicon carbide on the contacting fibers starts as early as at 450–500 °C.

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“…The main method for controlling the distance between the fibers involves the pressing of a precursor fiber package, followed by pyrolysis in a pre-stressed state. Specifically, the stable distance between the carbon fibers within organomorphic carbon preform (OCP)-about 10-40 µm -makes it possible to fabricate thin (0.3-0.4 mm) radio-frequency ion thruster electrodes (instead of molybdenum ones) from a carbon-carbon composite showing a high degree of surface purity [5], as well as to replace the graphite chase of the hot pressing mold with an OCP-based carbon-carbon one [6].…”

Section: Introductionmentioning

confidence: 99%

Organomorphic Carbon Preform Formation Mechanism

Bogachev

2022

J. Compos. Sci.

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Looking for ways to increase the structural uniformity of ceramic matrix composites (CMC) resulted in the development of organomorphic composites (C/C, C/SiC, SiC/SiC) where the filament diameter is comparable to the space between the filaments. The structural uniformity of the aforesaid CMCs is determined by their reinforcing preform; however, the mechanism of formation of this structure from polymer fibers remains unclear. This paper discusses an investigation of pressed specimens of the OKSIPAN® nonwoven fabric based on Pyron® polyacrylonitrile (PAN) fibers that were underoxidized as was determined using the electron paramagnetic resonance and microtomography methods. Using electron scanning microscopy, thermomechanical analysis and X-ray tomography, cementation of the preform due to the release and condensation of readily-polymerizing resin-like substances on the fiber surface after pressing at 180 °C was shown to be mainly responsible for retaining the mutual positions occupied by the fibers during pressing. The carbonized residue of the resin-like substances binds the fibers after pyrolysis. The other reason for organomorphic carbon preform consolidation is autohesive interaction of insufficiently cross-linked cores of the PAN fibers, since their thermal oxidation during pyrolysis at up to 1000 °C is hindered by the relatively high density of the compressed polymer preforms. The combination of pressing, thermal stabilization and pyrolysis results in the formation of the organomorphic carbon preform that features a relative density of at least 0.3 and a collection of pores, their normalized diameter ranging between 4 and 40 μm.

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An Ion Thruster Accelerating Electrode Made of Carbon-Carbon Composite Material

Cited by 6 publications

References 5 publications

Ion Electric Propulsion System Electric Breakdown Problems: Causes, Impacts and Protection Strategies

Ion Electric Propulsion System Electric Breakdown Problems: Causes, Impacts and Protection Strategies

Organomorphic Silicon Carbide Reinforcing Preform Formation Mechanism

Organomorphic Carbon Preform Formation Mechanism

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