Densification and Mechanical Properties of Al sub 2 O sub 3 --Si sub 3 N sub 4 Whisker Composite Ceramics

• Published in: Nihon Seramikkusu Kyōkai gakujutsu ronbunshi Vol. 97; no. 11; pp. 1424 - 1427
• Main Authors: Kondoh, I, Asahina, M, Tamari, N
• Format: Journal Article
• Language: Japanese
• Published: 01.11.1989
• ISSN: 0914-5400

alpha -Al sub 2 O sub 3 -- beta -Si sub 3 N sub 4 whisker composite ceramics with a whisker content of 20 wt.% were prepared by hot-pressing at prescribed temperature between 1300-1800 deg C for 30 min under the pressure of 30 MPa. Fairly dense composites were obtained at sintering temperature > 1500 deg C. The composites obtained < 1700 deg C consisted of alpha -Al sub 2 O sub 3 and beta -Si sub 3 N sub 4 , while beta '-sialon was produced in the composite sintered at 1800 deg C. The composite fired at 1600 deg C had a bending strength of approx 620 MPa, whose value was 50% larger than that of hot-pressed Al sub 2 O sub 3 at the same sintering temperature, but could not exceed the maximum bending strength of monolithic Al sub 2 O sub 3 ( approx 830 MPa). The fracture toughness (4.3-4.8 MPa m exp 1/2 ) was 1.5 times as large as that of Al sub 2 O sub 3 sintered at 1400-1600 deg C. Graphs, Photomicrographs. 8 ref.--AA