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In this paper, SiC particles of different particle sizes were used as aggregates to prepare SiC porous ceramics (50-70 mesh, 70-80 mesh and 80-90 mesh), and their flexural strength, filtration pressure drop and porosity were tested. On this basis, SiC with 80-90 mesh size was used as the aggregate, and the properties of porous ceramics were measured by using different proportions of pore-making agent. The results showed that when SiC particles were 80-90 mesh and the ratio of pore-making agent was 2:1, the samples prepared at 1300°C for 1.5h had the best comprehensive performance, the porosity was 33.9%, the flexural strength was up to 38.28MPa, and the filtration pressure drop was relatively low.

In order to explore the microstructures and ferroelectric properties of the Ca-doped BaTiO3 nanotubes, anodic oxidation method was used to generate TiO2 nanotubes. As a template to TiO2 nanotubes, hydrothermal synthesis method was used to prepare the Ca-doped BaTiO3 nanotubes. The microstructures and ferroelectric properties of the Ca-doped BaTiO3 nanotubes arrays, which had gained under different concentrations of calcium hydroxide, was measured and analyzed by scanning electron microscopy(SEM), X-ray diffraction instrument and ferroelectric analyzer respectively. The experiments show that with the increase of Ca(OH)2 concentration, TiO2 nanotubes can be transformed into Ba(1-x)CaxTiO3 nanotubes, and the crystallinity is improved. The Ca(OH)2 doping amount can improve the ferroelectric properties of Ba(1-x)CaxTiO3. When the Ca(OH)2 doping amount is 12%, residual polarization strength of the Ba(1-x)CaxTiO3 nanotubes is up to 1.32 µC/cm2 and coercive field can reach 3.37 kV/cm.

In this paper, the microstructure and ferroelectric properties of Ba(1-x-y)CaxCe2y/3TiO3 nanotubes were prepared by hydrothermal method using TiO2 nanotube as templates. Ba(1-x-y)CaxCe2y/3TiO3 nanotubes at different concentration of Ca(CH3COO)2•H2O and (CH3CO2)3Ce·xH2O were investigated. The experimental results show that increasing the concentration of (CH3CO2)3Ce·xH2O and Ca(CH3COO)2•H2O are beneficial to the transition of TiO2 nanotubes to Ba(1-x-y)CaxCe2y/3TiO3 nanotubes and improve ferroelectricity, and the results show that in the Ca(CH3COO)2•H2O, (CH3CO2)3Ce·xH2O doping concentration of 0.032mol/L,0.008mol/, respectively, the surface morphology of Ba(1-x-y)CaxCe2y/3TiO3 nanotubes is the best. Typical hysteresis loops with remanent polarization and coercive field are 0.33 μC/cm2, and 33 kV/cm, respectively.