부산대학교 도서관

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.matchemphys.2005.06.042 Byline: J.Q. Li (a), K.M. Gu (a), J.N. Tang (a), S.H. Xie (a), Y.H. Zhuang (b) Keywords: Reactive hot pressing; Al.sub.2O.sub.3-NiCrAl composite; Functional gradient materials Abstract: Al.sub.2O.sub.3-NiCrAl composites were fabricated by mixing NiO, Al and Cr powders and then reactive hot pressing. The high temperature alloy NiCrAl was formed by the reaction of extra Al, Cr and the Ni reduced from NiO. The Al.sub.2O.sub.3-NiCrAl composites with various Al.sub.2O.sub.3 fractions were successfully fabricated by the proper addition of extra Ni, Cr, Al or Al.sub.2O.sub.3 powders. A five-layer functional gradient material of YSZ-NiCrAl was fabricated using the Al.sub.2O.sub.3-NiCrAl composites with 25, 52.2 and 75vol.% Al.sub.2O.sub.3 as interlayers. The results from XRD analysis, optical microscope observation and thermal cycling test show that the composites fabricated by this method consist of [alpha]-Al.sub.2O.sub.3 phase and (Ni, Cr, Al) solid solution mainly, together with a small amount of NiAl. The [alpha]-Al.sub.2O.sub.3 grains formed by this in situ reaction between NiO and Ni are ultrafine and uniformly distributed. The three-point bending strength for the composite with 52.2vol.% Al.sub.2O.sub.3 is 363.5MPa. No cracking was found in the functional gradient materials after 10 thermal cycles up to 1000[degrees]C. It shows that the composites and the functional gradient material fabricated in this work have good strength, good resistance to oxidation and thermal shock. Author Affiliation: (a) Department of Materials Science and Engineering, Shenzhen Key Laboratory of Special Functional Materials, Shenzhen University, Shenzhen 518060, PR China (b) Institute of Materials Science, Guangxi University, Nanning 530004, PR China Article History: Received 4 November 2004; Revised 10 June 2005; Accepted 19 June 2005