Sialon Ceramics Prepared by Using CaH2 as a Sintering Additive
2008 (English)In: Journal of the American Ceramic Society, ISSN 0002-7820, Vol. 91, no 9, 2997-3004 p.Article in journal (Refereed) Published
In developing elongated a-sialon grains, a nitrogen-rich liquidphase sintering method was introduced by using CaH2 as asintering aid, so as to vary the N/O ratio of the liquid phaseformed in the sintering process while keeping the Si/Al ratiosconstant. With increasing addition the phase contents changedfrom single b-sialon to dual b/a-sialons and to single Ca-a-sialon.At low N/O ratios the microstructures contained mainlyequiaxed b-sialon grains, and at high N/O ratios well facetedelongated Ca-a-sialon grains. The improved toughness(KIC57.8 MPa .m1/2) and hardness (HV10517.5 GPa) propertiescan be attributed to the formation of interlocked microstructures.High-temperature compressive deformation testsindicated that the deformation onset temperature is determinedmainly by the Si/Al and N/O ratios, whereas the deformationrate is affected by the microstructure, i.e., the morphology andamounts of elongated a-sialon grains and residual glass phase,especially for the sialons with low N/O ratios.
Place, publisher, year, edition, pages
2008. Vol. 91, no 9, 2997-3004 p.
IdentifiersURN: urn:nbn:se:su:diva-25767DOI: 10.1111/j.1551-2916.2008.02549.xISI: 000259151000035OAI: oai:DiVA.org:su-25767DiVA: diva2:200491
Part of urn:nbn:se:su:diva-85682009-02-262009-02-172012-03-23Bibliographically approved