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Reactive Infiltration (reactive + infiltration)

Distribution by Scientific Domains
Polymers and Materials Science100%

Selected Abstracts

Manufacture of Biomorphic SiC Components with Homogeneous Properties from Sawdust by Reactive Infiltration with Liquid Silicon

JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 4 2010
Noelia R. Calderon
Biomorphic SiC components with homogeneous properties were manufactured from sawdust using a novel method to produce preforms, without addition of any extra binder, but with enough mechanical strength to be carbonized up to 1400°C without deformation. Reactive infiltration of carbon preforms of an adequate open porosity with liquid silicon has been successfully used to prepare biomorphic components. Moreover, the modification of bioSiC properties induced by the structural rearrangement of carbon preforms when they are further heat treated at 2500°C was additionally studied. BioSiC components showed a maximum in bending strength when the material is processed from carbon preforms exhibiting around 40% of open porosity, which seems to be the optimum value for carbon preforms treated at 1400° and 2500°C. However, the heat treatment of the carbon preforms at 2500°C produced bioSiC components with a finer and more homogeneous microstructure than those obtained from carbon preforms treated at 1400°C, improving their bending strength up to 22%. [source]

Aluminum Infiltration into Molybdenum Silicide Preforms

JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 9 2002
Anup K. Bhattacharya
The presence of Mo5Si3 in MoSi2 preforms hinders the reactive infiltration of aluminum. To understand the role of Mo5Si3, the kinetics of aluminum infiltration into pure Mo5Si3 is studied. Irrespective of the initial composition (MoSi2 or Mo5Si3) of the preform, the final product always contains Mo(Al,Si)2. However, the aluminum content in the two cases is different: when the preform is MoSi2, the aluminum content is 14,18 at.%, and, when the preform is Mo5Si3, the aluminum content is 25,27 at.%. The activation energy for the reactive infiltration of aluminum into the Mo5Si3 preform is ,26 kJ/mol. [source]

Degradation processes in Al/SiCp/MgAl2O4 composites prepared from recycled aluminum with fly ash and rice hull ash

MATERIALS AND CORROSION/WERKSTOFFE UND KORROSION, Issue 11 2007
M. I. Pech-Canul
The degradation characteristics of Al/SiCp/spinel composites prepared with fly ash (FA) and rice hull ash (RHA) under environmental conditions were investigated. Composite specimens were prepared with recycled aluminum via reactive infiltration in the temperature range 1050,1150,°C for 50,70 min and, in argon atmosphere at a pressure slightly above that of the atmospheric pressure. Results reveal that although both FA and RHA help in preventing SiCp dissolution and the subsequent chemical degradation of the composites, due to the interaction of native carbon in FA with liquid aluminum, FA-composites are susceptible to corrosion via Al4C3. Moreover, this phase accelerates the degradation process and increases the damage severity. The primary corrosion mechanism in both types of composites is attributed to microgalvanic coupling between the intermetallic Mg2Si and the matrix. Accordingly, an appropriate control of the Si/(Si,+,Mg) molar ratio in the aluminum alloy hinders the Mg2Si corrosion mechanism in both types of composites and a proper FA calcination prevents chemical degradation in FA composites. [source]