Octacalcium phosphate (OCP) has attracted the interest of researchers looking for new biomaterials due to its excellent biocompatibility and high formability. Furthermore, it was an attraction for medical combination products that ions and molecule doping ability of OCP, which originated its distinct crystal structure. Then, as an antibacterial bone substitute, Ag-substituted OCP (OCP-Ag) was a candidate of a centerpiece. However, for OCP-Ag block fabrication, drawback Ag contents of OCP-Ag blocks were significantly reduced compared to OCP-Ag powder when they were fabricated in the same Ag concentration solutions. It was still unclear the role of Na, an important matter for OCP block structure fabrication, in Ag substitution into OCP unit lattice. Thus, in this study, we analyzed the Na and Ag substitution process into OCP during OCP fabrication in the presence of Na and Ag solutions. Both cations improved the OCP’s layer structure, even though both ions co-exist. As the concentration of Na in the solutions increased, Ag contents of samples decreased until threshold values were achieved. According to the ionic species analysis, both PO4 ion complexes of Na and Ag showed no tendency toward other cation concentrations. Spectroscopic investigation showed that both ions were substituted in the conjugated site of P5 PO4, resulting in a competition of Ag and Na substitution into the same.
After La2Mo2O9 (LMO), Cu-substituted LMO (LCuMO), and CuMoO4 (CuMO) powders were prepared by complex polymerization method or oxide mixing method, their antiviral and antifungal activities were evaluated. The obtained samples were powders having a crystal structure of either La2Mo2O9 or CuMoO4 with specific surface area of 3.0–6.0 m2/g. These samples exhibited almost equal antiviral activity against bacteriophage Qβ, whereas CuMO was found to have the highest antiviral activity against bacteriophage Φ6. An antifungal activity test based on JIS Z 2911 showed LCuMO and CuMO to have high activity; CuMO had high antiviral and antifungal activity. In fact, CuMO had a large amount of ion leakage to the inoculated suspension. The Cu ion leakage was promoted by that of molybdate ion. The high antifungal activity of CuMO was inferred as attributable to the large amount of ion leakage and the generation of reactive oxygen species.
Using stainless steel slag (SSS) and coal fly ash as raw materials to prepare glass-ceramics with excellent properties, the toxic and unstable Cr (VI) in the SSS was non-toxic converted into Cr (III). By Differential scanning calorimetry (DSC), X-ray diffraction (XRD), Scanning electron microscope (SEM) and performance testing methods, the relationship among phase composition, microstructure and properties of the CaO–MgO–Al2O3–SiO2 (CMAS) system slag glass-ceramics prepared at Tg = 750 °C and Tc = 950 °C was studied (Tg, glass transition temperature; Tc, crystalline temperature). The heavy metal Cr was solidification in the slag glass-ceramics by the toxicity characteristic leaching procedure (TCLP), which was satisfied the limitation of standard “DZ/T 0279.2-2016” of China and the solidifying effect of glass-ceramics was more obvious than that of glasses. The detoxification effect was verified through X-ray photoelectron spectroscopy (XPS). The experimental results showed that the physical performance of glass-ceramics increased with the increase of the content of SSS. As for the products from the mixed sources, the best product properties of G42 (1.05 wt % Cr2O3) glass-ceramics (bending strength, 230.58 ± 13.21 MPa; hardness, 878.30 ± 18 N/cm2) was the SSS content of 21 %. Moreover, the generation of spinel phase was the key crystal phase for solidifying heavy metal Cr. With the increase of the SSS, the spinel phase increased. In contrast, G42 was the most superior product performances of solidified Cr. In addition, it can be found that the unstable ratio (UR) of G42 is the smallest (UR = 0.01544) for heavy metal Cr in the leaching solution. It was further confirmed that the heavy metal Cr is effectively solidified in the glass-ceramics.
In this work, based on the sol–gel titration technology, the method to prepare the composite beads with different diameters which range from 0.1 to 0.8 mm is researched. The detail studies on the preparation conditions which include the sol viscosity, sol specific gravity and size of discharge needle are proposed. The relationships between the preparation conditions and the final diameter of the prepared composite beads are obtained. The Scanning Electron Microscope (SEM) test results show that the composite beads have uniform size and good sphericity. The surface grains are basically similar to the cross-section grains. No obvious pores exist, and there is no abnormal large grain size. The particle size distribution test results show that the composite beads have relatively concentrated size distribution. The density test results show that the composite beads are dense and contain few pores.
Fabrication of Al2O3/SiC composite has attracted much worldwide attention due to numerous advantages to compare with monolithic Al2O3, as improved bending strength and wear resistance, increased lifetime and inducing of self-crack-healing ability. As one of the conventional fabrication methods for Al2O3/SiC composites, through infiltration polycarbonsilane as SiC precursor in pre-sintered puros Al2O3 matrix and followed by thermal decomposition has been demonstrated. However, this method is limited because of two-step sintering process and high cost of polycarbosilane chemicals. The present work reports a novel approach to fabricate Al2O3/SiC composite by utilizing cost-effective 3-aminopropyltriethoxysilane as precursor of SiC, which is tailored on surface modified Al2O3. The moderate hydroxyl groups modified on Al2O3 surface by wet mechanochemical treatment are proved to be important to grafting organosilane on surface under continuous hydrolysis and condensation, which can convert into SiC after thermal pyrolysis. As a result, composite involving homogenous SiC particle distributed Al2O3 matrix is successfully fabricated.