Synthesis and vibration spectroscopy of nano-sized manganese oxides

The present study has been supported by the Latvian National Research Program IMIS2. One of us, IS, was supported by MES RF RFMEFI61615X0064.X-ray diffraction, micro-Raman and the Fourier transform infrared spectroscopies as well as magnetometry measurements were performed on nanosized manganese oxides to probe their phase composition and magnetic properties. It was shown that the XRD method is less sensitive to phase composition of manganese oxide samples than spectroscopic methods. While in some samples the XRD method recognised only the manganosite MnO phase, the Raman and FT-IR methods revealed additionally the presence of the hausmannite Mn3O4 phase.Ministry of Education and Science RF RFMEFI61615X0064; Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART

Synthesis and vibration spectroscopy of nano-sized manganese oxides

The present study has been supported by the Latvian National Research Program IMIS2. One of us, IS, was supported by MES RF RFMEFI61615X0064.X-ray diffraction, micro-Raman and the Fourier transform infrared spectroscopies as well as magnetometry measurements were performed on nanosized manganese oxides to probe their phase composition and magnetic properties. It was shown that the XRD method is less sensitive to phase composition of manganese oxide samples than spectroscopic methods. While in some samples the XRD method recognised only the manganosite MnO phase, the Raman and FT-IR methods revealed additionally the presence of the hausmannite Mn3O4 phase.Ministry of Education and Science RF RFMEFI61615X0064; Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART

Synthesis, Sintering and Characteristics of Hydroxyapatite Nanopowder

The chemical interaction between calcium hydroxide and phosphoric acid was chosen for synthesis of the HAP nanopowder. Various methods for manufacturing dense HAP materials from obtained powders were used and compare

Synthesis, Sintering and Characteristics of Hydroxyapatite Nanopowder

Synthesized HAP nanopowder shows the agglomerate which consist of nanosized rod-shaped particles in size of 50–100 nm. The powder obtained by spray-drying consisted from quasi spherical granules with average diameter of 20-40 μm.The specific surface area of such powder was in the range of 60-70 m2/g. The XRD pattern of the powder showed low crystallinity.The specific surface area of such powder was in the range of 60-70 m2/g. The XRD pattern of the powder showed low crystallinity.All used methods allows to manufacture the dense HAP materials but more promising method seems to be the MW sintering because only this method allows to obtain dense HAP material at relatively low temperature and in short time – at 900 oC in 15 minutes (Table 1). This provides the saving of nanosize microstructure of the material and therefore the high values of fracture toughness up to 1.5 MPa·m1/2, microhardness up to 5 GPa

Lithium Ion Conductors in the System Li4xTi1-xP2O7 ( x= 0; 0,06; 0,2)

The powder of Li4xTi1-xP2O7 (x = 0.06, 0.1, 0.2) pyrophosphates - potentially suitable electrode materials for lithium secondary batteries - have been synthesized by solid state reaction. The analysis of the XRD patterns showed that these pyrophosphates have cubic 3x3x3 superstructure (S.G. Pa ) with 108 formula units in the supercell. The complex electrical conductivity were carried out in air from 400 K to 720 K and in the frequency range from 10 Hz to 3 GHz. Two relaxation dispersion regions in conductivity spectra were foun

The Influence of Surface Treatment by Hydrogenation on the Biocompatibility of Different Hydroxyapatite Materials

The influence of hydrogenation on the biocompatibility of different hydroxyapatite (HAP) materials was tested. Materials consisted of pure HAP, HAP substituted with manganese (Mn+2) and with magnesium (Mg+2) - all axially pressed and conventionally sintered for 2 h at 1200 degrees C; pure HAP isostatic pressed and sintered by a microwave technique for 15 min at temperature of 1200 degrees C. Biocompatibility was compared by enumeration of the number of osteoblast-like cells to the materials before and after hydrogenation. Obtained results show that the osteoblastic cells demonstrated a higher ability to attach to HAP if its surface was negatively charged. Hydrogenation altered the surface potential; HAP substituted with manganese - HAP(Mn) and with magnesium - HAP(Mg) demonstrated the highest ability to engineer the charge

The Influence of Surface Treatment by Hydrogenation on the Biocompatibility of Different Hydroxyapatite Materials

The influence of hydrogenation on the biocompatibility of different hydroxyapatite (HAP) materials was tested. Materials consisted of pure HAP, HAP substituted with manganese (Mn+2) and with magnesium (Mg+2) – all axially pressed and conventionally sintered for 2 h at 1200 °C; pure HAP isostatic pressed and sintered by a microwave technique for 15 min at temperature of 1200 °C. Biocompatibility was compared by enumeration of the number of osteoblast-like cells to the materials before and after hydrogenation. Obtained results show that the osteoblastic cells demonstrated a higher ability to attach to HAP if its surface was negatively charged. Hydrogenation altered the surface potential; HAP substituted with manganese – HAP(Mn) and with magnesium – HAP(Mg) demonstrated the highest ability to engineer the charge

Processing of dense nanostructured HAP ceramics by sintering and hot pressing

A nanosized HAP powder was sintered and hot pressed, in order to obtain dense HAP ceramics. In a first series of experiments, the powder was isostatically pressed into uniform green compacts and sintered at temperatures ranging from 1000 degrees C to 1200 degrees C in air atmosphere for different times. In a second series, the isostatically pressed green compacts were hot pressed in argon atmosphere at 900 degrees C, 950 degrees C and 1000 degrees C. The SEM micrograph of the sample sintered at 1200 degrees C for 2 h showed a uniform 3 mu m mean grain size dense microstructure. In the case of hot pressed HAP compacts, full dense, translucent nanostructures were obtained having mean grain size below 100 nm and improved mechanical properties. With the grain size decreasing from 3 mu m to 50 nm, the fracture toughness of pure HAP ceramics increased from 0.28 MPa m(1/2) to 1.52 MPa m(1/2)