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The c-axis texturing of seeded Si3N4 with β-Si3N4 whiskers by slip casting in a rotating magnetic field / X.W. Zhu in Acta materialia, Vol. 58 N° 1 (Janvier 2010) 

Public ISBD [article]  in Acta materialia > Vol. 58 N° 1 (Janvier 2010) . - pp. 146–161 Titre : The c-axis texturing of seeded Si3N4 with β-Si3N4 whiskers by slip casting in a rotating magnetic field Type de document : texte imprimé Auteurs : X.W. Zhu, Auteur ; Y. Sakka, Auteur ; T.S. Suzuki, Auteur Année de publication : 2010 Article en page(s) : pp. 146–161 Note générale : Métallurgie Langues : Anglais (eng) Mots-clés : Silicon  nitride  Slip  casting  Rotating  magnetic  field  Texture  Thermal  conductivity Résumé : The c-axis texture development in seeded Si3N4 with β-Si3N4 whiskers by slip casting in a rotating magnetic field was investigated by powder X-ray diffraction, scanning electron microscopy and thermal anisotropy evaluation, including the effects of magnetic flux density, suspension rheological properties and rotational speed. By increasing the magnetic flux density from 1 to 12 T, the c-axis orientation of β-Si3N4 whiskers is achieved in the well-dispersed 30 vol.% suspension but hindered in the flocculated 40 vol.% suspension. The degree of orientation tends to decrease with increasing rotational speed from 5 to 30 rpm. The green body shows no density gradient but nonuniform orientation of β-Si3N4 whiskers regardless of the rotational speed, resulting in the similar nonuniform texture in the sintered body. The nonuniform texture is featured in three major layers: lower surface, inner region and upper surface, corresponding to the lower, higher and lower c-axis orientation, respectively. The resultant c-axis textured Si3N4 exhibits thermal anisotropy as high as 55%, slightly lower than the intrinsic thermal anisotropy (62%) of β-Si3N4. A theoretical analysis is performed to help understand the key factors affecting the orientation of β-Si3N4 whiskers by slip casting in the rotating magnetic field. The formation mechanisms of the nonuniform texture were discussed. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science/article/pii/S1359645409005886 [article] The c-axis texturing of seeded Si3N4 with β-Si3N4 whiskers by slip casting in a rotating magnetic field [texte imprimé] / X.W. Zhu, Auteur ; Y. Sakka, Auteur ; T.S. Suzuki, Auteur . - 2010 . - pp. 146–161. Métallurgie Langues : Anglais (eng) in Acta materialia > Vol. 58 N° 1 (Janvier 2010) . - pp. 146–161 Mots-clés : Silicon  nitride  Slip  casting  Rotating  magnetic  field  Texture  Thermal  conductivity Résumé : The c-axis texture development in seeded Si3N4 with β-Si3N4 whiskers by slip casting in a rotating magnetic field was investigated by powder X-ray diffraction, scanning electron microscopy and thermal anisotropy evaluation, including the effects of magnetic flux density, suspension rheological properties and rotational speed. By increasing the magnetic flux density from 1 to 12 T, the c-axis orientation of β-Si3N4 whiskers is achieved in the well-dispersed 30 vol.% suspension but hindered in the flocculated 40 vol.% suspension. The degree of orientation tends to decrease with increasing rotational speed from 5 to 30 rpm. The green body shows no density gradient but nonuniform orientation of β-Si3N4 whiskers regardless of the rotational speed, resulting in the similar nonuniform texture in the sintered body. The nonuniform texture is featured in three major layers: lower surface, inner region and upper surface, corresponding to the lower, higher and lower c-axis orientation, respectively. The resultant c-axis textured Si3N4 exhibits thermal anisotropy as high as 55%, slightly lower than the intrinsic thermal anisotropy (62%) of β-Si3N4. A theoretical analysis is performed to help understand the key factors affecting the orientation of β-Si3N4 whiskers by slip casting in the rotating magnetic field. The formation mechanisms of the nonuniform texture were discussed. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science/article/pii/S1359645409005886