ROSA MARIA DA ROCHA
6 resultados
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Artigo IPEN-doc 20118 Ceramic substrates of ' Beta"-SiC/SiAlON composite from preceramic polymers and Al-Si fillers2014 - ROCHA, R.M.; BRESSIANI, J.C.; BRESSIANI, A.H.A.Artigo IPEN-doc 11391 Obtencao de substratos ceramicos no sistema Si-Al-O-N-C empregando polissiloxanos e cargas de Si e Alsub(2)Osub(3)2005 - ROCHA, R.M.; SCHEFFLER, M.; GREIL, P.; BRESSIANI, J.C.; BRESSIANI, A.H.A.Artigo IPEN-doc 08208 Sintering behavior of the Alsub(2)Osub(3)-NbC composites with Ysub(2)Osub(3) addition2001 - ROCHA, R.M.; BRESSIANI, J.C.; BRESSIANI, A.H.A.Artigo IPEN-doc 09689 Development and characterisation of Si-Al-O-N-C ceramic composites from polysiloxane-filler mixtures2003 - ROCHA, R.M.; GREIL, P.; BRESSIANI, J.C.; BRESSIANI, A.H.A.Artigo IPEN-doc 11147 Complex-shaped ceramic composites obtained by machining compact polymer-filter mixtures2005 - ROCHA, R.M.; GREIL, P.; BRESSIANI, J.C.; BRESSIANI, A.H.A.Research in the preparation of ceramics from polymeric precursors is giving rise to increased interest in ceramic technology because it allows the use of several promising polymer forming techniques. In this work ceramic composite pieces were obtained by pyrolysis of a compacted mixture of a polysiloxane resin and alumina/silicon powder. The mixture consists of 60 vol% of the polymer phase and 40 vol% of the filler in a 1:1 ratio for alumina/silicon, which was hot pressed to crosslink the polymer, thus forming a compact body. This green body was trimmed into different geometries and pyrolised in nitrogen atmosphere at temperatures up to 1600 °C. X-ray diffraction analysis indicated the formation of phases such as mullite and Si2ON2 during pyrolysis, that result from reactions between fillers, polymer decomposition products and nitrogen atmosphere. The porosity was found to be less than 20% and the mass loss around 10%. The complex geometry was maintained after pyrolysis and shrinkage was approximately 8%, proving pyrolisis to be a suitable process to form near-net-shaped bulk ceramic components.Artigo IPEN-doc 14850 Effect of electron beam radiation dose on the foam formation in pre-ceramic polymer2010 - ROCHA, ROSA M. da; MOURA, ESPERIDIANA A.B.; BRESSIANI, JOSE C.; BRESSIANI, ANA H.A.