Fabrication of nickel aluminide intermetallic-alumina nanocomposite via reaction synthesis
✍ Scribed by R. Ismail; I.I. Yaacob
- Publisher
- Elsevier Science
- Year
- 2008
- Tongue
- English
- Weight
- 232 KB
- Volume
- 200
- Category
- Article
- ISSN
- 0924-0136
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✦ Synopsis
Nickel aluminide-alumina nanocomposite was prepared by a conventional powder metallurgy technique. Nanosize alumina as dispersed phase was mixed with Ni and Al powder in a planetary ball mill for 4 h at 175 rpm. The mixture was then compacted using a hydraulic press at 400 MPa for 15 min. Sintering was done under inert condition in a tube furnace at 660 • C with 5 h soaking time. The occurrence of reaction synthesis during sintering was detected by the presence of a 'large' exothermic peak of the differential thermal analysis curve, which occurred below 600 • C. The hardness value for the composite containing 5% alumina was about two times higher than Ni 3 Al intermetallic. Its saturation magnetization (M s ) was very low indicating the presence of a small amount of elemental Ni. X-ray diffraction (XRD) measurements showed peaks corresponding to Ni-Al and Ni 3 Al indicating the formation of the desired intermetallics.