Preparation and properties of reticulated porous γ-Y2Si2O7 ceramics with high porosity and relatively high strength

Dense y-Y2Si2O7 ceramics are promising silicates with very low thermal conductivity, good damage tolerance and hot corrosion resistance. However, processing of porous gamma-Y2Si2O7 was not reported in early literatures. In this paper, reticulated porous gamma-Y2Si2O7 ceramics with high porosity (similar to 85%) and relatively high compressive strength (similar to 1.28 MPa) are successfully fabricated by the polymeric sponge impregnation method. The main compositions of the slurry are Y2SiO5 and silica sol. Samples are sintered at the temperature of 1550 degrees C to obtain porous gamma-Y2Si2O7 ceramics by reaction bonding; and the samples are recoated 3 times to enhance the compressive strength of porous ceramics. Scanning electron microscopy and X-ray tomography investigations show that the pore size distribution of the as-prepared porous gamma-Y2Si2O7 ceramic ranges from 200 to 700 mu m; meanwhile, the sample possesses fully open and highly interconnected pores. Influences of pretreatments of sponge on the compressive strengths of samples are also investigated. This work reports a new porous ceramic material (gamma-Y2Si2O7) with high permeability, high strength and controllable macrostructure. (C) 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved.