遠心フィルター成形法を用いた窒化ケイ素系積層複合材料の作製

概要

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Silicon nitride powder calcined with yttria-rich or alumina-rich additives(total 10 mol%)was alternately accumulated into layers by centrifugal filter-pressing; a combination of filter-pressing and centrifugal shape forming. The subsequent sintering at 1800℃ in 1.0 MPa N_2 atmoshere provided sintered composites(SN-MLCs)with more than 98% density and 60 μm thick of each layer. Elongated rodlike grains characteristic of yttria-rich additives were periodically observed in the SN-MLCs at the calcination temperature of 1400℃. At a high calcination temperature(1450℃), the difference in microstructure between layers became smaller. It was considered that the diffusion of a part of the additives through the layer interface reduced the interlayer stress to prevent delamination during sintering. The crack length propagated from Vickers indents on the SN-MLCs was shorter than that on the monolithic materials. The shorter crack length and interlayer fracture observed for SN-MLCs suggested a possibility of toughening.
社団法人日本セラミックス協会の論文
1995-10-01