PLUCKNETT, KEVIN P.QUINLAN, MERVINGARRIDO, LILIANAGENOVA, LUIS2014-07-152014-07-302014-07-152014-07-302008PLUCKNETT, KEVIN P.; QUINLAN, MERVIN; GARRIDO, LILIANA; GENOVA, LUIS. Microstructural development in porous beta-Sisub(3)Nsub(4) ceramics prepared with low volume REsub(2Osub(3)-MgO-(CaO) additions (RE=La,Nd,Y,Yb). <b>Materials Science and Engineering, A</b>, v. 489, p. 337-350, 2008. DOI: <a href="https://dx.doi.org/10.1016/j.msea.2007.12.023">10.1016/j.msea.2007.12.023</a>. Disponível em: http://repositorio.ipen.br/handle/123456789/5069.0921-5093http://repositorio.ipen.br/handle/123456789/5069Porous β-Si3N4 ceramics have a wide range of potential applications, including filters for hot gases or molten metals, bioreactor supports and lightweight structural components. In the present study, a new approach is taken for the production of porous β-Si3N4 ceramics based on compositional design. A low volume fraction of multiple sintering aids is employed, where each additive is designed to play one or more specific roles in the sintering behavior and microstructural development of β-Si3N4 (e.g. densification, α- to β-Si3N4 transformation, anisotropic β-Si3N4 whisker growth, debonding aid). The primary aim of this work was to develop β-Si3N4 ceramics with a more porous microstructure than in prior work (ideally with 20–40 vol.% porosity), while developing high grain aspect ratios (i.e. >10:1) such that good mechanical performance can be expected. Compositions are based on various ratios of RE2O3:MgO, where RE = La, Nd, Y or Yb, with selected materials also prepared with small CaO additions. Sintering has been conducted in a nitrogen atmosphere (0.1 MPa), at temperatures between 1400 and 1700 °C. The influence of sintering aid composition and sintering temperature has been assessed. Particular attention was paid to microstructure development, including: densification behavior, retained pore size, the extent of α- to β-Si3N4 transformation, and the evolution of β-Si3N4 grain aspect ratios.337-350openAccessceramicsporous materialssilicon nitridessilicon oxidesgrain growthscanning electron microscopyArtigo de periódico48910.1016/j.msea.2007.12.023https://orcid.org/0000-0002-5172-5082