Design and test of a Maximum Power Point Tracking System for UNISAT-3 Microsatellite
- Paper number
IAC-04-R.2.01
- Author
Prof. Fabio Santoni, University of Rome "La Sapienza", Italy
- Year
2004
- Abstract
Quartz fiber reinforced silicon nitride composites were prepared with quartz fibric and polysilazane by PIP (precursor infiltration and pyrolysis) method. The polysilazane shows good infiltration property. The density of the composites reaches 1.95 g/cm3 after 7 PIP circles. The values of the dielectric properties of the composites are stable with the dielectric constants varying from 3.20 to 3.25 and the dielectric losses varying from 0.001 to 0.003 after the exposition of samples in air for 422 days. The composites also possess good temperature-frequency characteristics under the test conditions with frequency of 7-19 GHz and temperature of RT-1473 K, the variation ratio of the dielectric constant is lower than 5% and the dielectric loss keeps below 0.0017. The composites show a mass ablation rate of 0.0151g/cm2•s and a flat ablated surface when the surface temperature of the samples is hold at 2773 K. Fracture analysis indicates that the SiO2/Si3N4 composites are brittle which is caused by strong-bonding interface between the fiber and the matrix. A week-bonding interface layer of BN was designed and introduced to the composites which is proved to be an effective way to improve the mechanical property. The results show that SiO2 fiber reinforced SiO2/Si3N4 composite is a promising candidate for thigh temperature microwave transparent materials.
- Abstract document
- Manuscript document
IAC-04-R.2.01.pdf (🔒 authorized access only).
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