Porous b-SiC with a multimodal porosity preferentially oriented alongone direction is obtained by infiltration of pyrolyzed wood with Si at T>TSi Melting. Hard woods (obece, poplar and assembled poplar) are used as startingmaterials. The microstructure of the startingwood, of the wood after pyrolysis and after Si infiltration, is characterised in terms of overall porosity, pore size distribution and of crystallographic phases. The process is optimised for obtaining porous templates of only b-SiC with a microstructure that replicates the original wood microstructure. Features such as the presence of unreacted carbon, or conversely, of Si within the open pores of the infiltrated materials are minimized by a careful control of the amount of Si in contact with the carbon preform duringthe infiltration cycle. Compression tests on cubic samples are performed alongthe axial and longitudinal direction. # 2003 Elsevier Ltd. All rights reserved.
Bonding of zirconia su super alloy with the active brazing technique
D Sciti;A Bellosi;L Esposito
2001
Abstract
Porous b-SiC with a multimodal porosity preferentially oriented alongone direction is obtained by infiltration of pyrolyzed wood with Si at T>TSi Melting. Hard woods (obece, poplar and assembled poplar) are used as startingmaterials. The microstructure of the startingwood, of the wood after pyrolysis and after Si infiltration, is characterised in terms of overall porosity, pore size distribution and of crystallographic phases. The process is optimised for obtaining porous templates of only b-SiC with a microstructure that replicates the original wood microstructure. Features such as the presence of unreacted carbon, or conversely, of Si within the open pores of the infiltrated materials are minimized by a careful control of the amount of Si in contact with the carbon preform duringthe infiltration cycle. Compression tests on cubic samples are performed alongthe axial and longitudinal direction. # 2003 Elsevier Ltd. All rights reserved.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.