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Effect of niobia as an additive in phosphate-bonded alumina

Journal Article · · Materials Research Bulletin
 [1];  [2]
  1. Univ. Federal de Sao Carlos, Sao Paulo (Brazil). Dept. de Engenharia de Materiais
  2. Univ. de Sao Paulo, Sao Carlos, Sao Paulo (Brazil)

In this work a study was carried out on the Al{sub 2}O{sub 3}/Nb{sub 2}O{sub 5}/H{sub 3}PO{sub 4} system. A-2 alumina from Alcoa (Brazil) was used and the Al{sub 2}O{sub 3}/Nb{sub 2}O{sub 5}/H{sub 3}PO{sub 4} system with an Al{sub 2}O{sub 3}/P{sub 2}O{sub 5} molar ratio of 20.3, pressed at 20 and 60 MPa and thermally treated at 110, 300, 500, 800, 1,000, 1,200, 1,400 and 1,600 C, was studied. An attempt was made to relate mechanical properties with porosity as well as with the phases formed during heat treatment. X-ray diffraction (XRD), infrared spectroscopy (IRS) and magic-angle spinning phosphorus nuclear magnetic resonance ({sup 31}P MAS NMR) were used for phase detection. The amorphous AlPO{sub 4} was considered as the low temperature bonding phase. The system studied showed highest mechanical strength at 1,400 C.

OSTI ID:
215332
Journal Information:
Materials Research Bulletin, Journal Name: Materials Research Bulletin Journal Issue: 2 Vol. 31; ISSN MRBUAC; ISSN 0025-5408
Country of Publication:
United States
Language:
English