Ceramic materials able to heal manufacture or damage induced microstructure defects might trigger a change in paradigm for design and application of load bearing ceramics. This work reviews thermodynamic and kinetic aspects governing the regeneration of solid contact able to transfer stress between disrupted crack surfaces in ceramics. Major crack healing processes include perturbation of crack-like pores followed by sintering of isolated pores, as well as reaction with an environmental atmos...

Crystal structure of Ti₅Al₂C₃ was determined by means of X-ray powder diffraction (XRPD), transmission electron microscopy (TEM) and ab initio calculations. In contrast to the already known P6₃/mmc space group that the MAX phases crystallize, it was demonstrated that the R3&#...

Crystallographic and microstructural properties of Ho(Ni,Co,Mn)O_3±δ perovskite-type multiferroic material are reported. Samples were synthesized with a modified polymeric precursor method. The synchrotron X-ray powder diffraction (SXRPD) technique associated to Rietveld refinement method was used to perform structural characterization. The crystallographic structures, as well as microstructural properties, were studied to determine unit cell parameters and volume, angles and...

Mullite whiskers were prepared from Si powders in molten Al₂(SO₄)₃-Na₂SO₄ mixture salts with different Al/Si molar ratio (R) of raw materials. The resulting mullite whiskers, had been investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and infrared spectroscopy analysis (FT-IR). Mullite phase was obtained in molten salts when the temperature reached at 850 ℃. S...

In this work, a phenomenological model is applied to describe the magnetocaloric effect for the La_0.75Ca_0.25MnO₃ system near a second-order phase transition from a ferromagnetic to a paramagnetic state. Based on this model, it can predict the values of the magnetocaloric properties from calculation of magnetization as a function of temperature under different external magnetic fields. The magnetic entropy change reaches a peak of about 5.39 J/(kg·K) at 257 K u...

Gadolinium gallium garnet (GGG) polycrystalline powders doped with Nd,Yb were prepared by coprecipitation method. The structure, phase and properties of powders were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS) and fluorescence spectroscopy. XRD analysis indicated that the crystallization of Nd,Yb:GGG powders occur at 900 ℃. SEM analysis showed that the morphology...

Increasing energy cost calls for exterior coatings with high near infra-red reflectance, so as to reduce heat absorption and in turn cost of air-conditioning. While modulations of substrate, use of white metal oxides as pigments or under-layers has been reported in past, reports on metal oxide or doped metal oxide pigments with high NIR reflectance is scarce. We report for the first time a blue colored cobalt aluminate type pigment prepared through doping of cerium, praseodymium or neodymium....

Dielectric composites made using P(VDF-CTFE) 88/12 mol% as polymer matrix and both micro-sized and nano-sized CaCu₃Ti₄O₁₂ (CCTO) particles as filler are developed. These composites exhibit high dielectric constant with a small dielectric loss. More importantly, it is found that the dielectric constant of these composites is almost independent of temperature from 25 ℃ to 125 ℃. Comparing the composites made using micro-sized CCTO particles, the co...

The xNi_0.83Co_0.15Cu_0.02Fe_1.9O_4－δ (NCCF) + (1−x)PbZr_0.52Ti_0.48O₃ (PZT) particulate magneto ferroelectric composites with x = 0, 0.1, 0.2, 0.3, 0.4, 0.5 and 0.6 mole fraction were prepared by conventional ceramic double sintering method. The presence of two phases (perovskite structure of ferroelectric phase and spinal structure of ferromagnetic phase) ...

Composite oxide ionic conductors consisting of Zr_0.85Y_0.15O_1.925 (YSZ) and La_9.33Si₆O₂₆ (LSO) have been synthesized by a modified coprecipitation method. X-ray diffraction, electron microscope, and complex impedance were adopted to investigate the phase component, microstructures, and conductivities, respectively. The results show that the average grain sizes of the composite powders and as-sintered pellets are less than 20 nm ...