Investigation of the ablation process of ZrB2-SiC materials by mass spectrometry

Reference	Presenter	Authors (Institution)	Abstract
14-090	Cristian Cley Parteniani Rita	Rita, C.C.(Instituto Tecnológico de Aeronáutica/ Faculdade de Tecnologia de São Paulo); Miranda, F.S.(Instituto Tecnológico de Aeronáutica); da Silva, R.J.(Instituto Tecnológico de Aeronáutica); Rocha, R.M.(Instituto de Aeronautica e Espaço); Essiptchouk, A.M.(Universidade Estadual Paulista); Petraconi Filho, G.(Instituto Tecnológico de Aeronáutica);	The objective of this work was to analyze the gas atmosphere generated by the ablative tests, by mass spectrometry, identifying the chemical components and their relative intensities when vaporized in the thermal oxidation process that occurs on the surface of the materials used in this experiment. Samples of pure ZrB2 and mixtures with 10, 20 and 30 vol% SiC were exposed to ablative tests in a hypersonic plasma wind tunnel to investigate the ablative properties of ultra high temperature (UHTC) ceramics of ZrB2-SiC composites. The tests were performed at low pressure in a reactive air plasma using an non-transferred DC arc plasma torch coupled to a hypersonic nozzle (Mach 5), with enthalpies of 17.36 MJ / kg at 26.12 MJ / kg, corresponding to heat fluxes of 0.52 MW / m2 to 2.2 MW / m2. The microstructural and chemical analysis on the surface of the samples was performed by SEM / EDS and XRD before and after ablative tests. Mass spectrometry was used as the method of analysis of the gaseous by-product generated in the ablation process. The detection of the gaseous materials generated in the thermal oxidation takes place simultaneously to the thermal ablation process. In this research the presence of SiO2, ZrO2, SiO, SiC and ZrB2 among others was observed, and the respective relative intensities were identified, indicating the oxide formation on the surface of the tested materials and showing that part of the oxide formed on the surface of the materials is expelled in the ablation process. And we conclude from this essay the importance of this technique of analysis completing the methodology of analysis of the experiments.
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