Effect of nano-TiO2 on properties of 3 mol% yttria-stabilized zirconia ceramic via layered extrusion forming

Porous Mullite Ceramic Modification with Nano-WO3

Mullite and mullite-alumina ceramics materials with dominance of the mullite phase are used in different areas of technology and materials science. Porous mullite ceramics materials can be used simultaneously as refractory heat insulators and also as materials for constructional elements. The purpose of this work was to investigate the WO₃ nanoparticle influence on the evolution of the aluminum tungstate and zircon crystalline phases in mullite ceramics due to stabilization effects caused by different microsize ZrO₂ and WO₃. The use of nano-WO₃ prevented the dissociation of zircon in the ceramic samples with magnesia-stabilized zirconia (MSZ), increased porosity by approximately 60 ± 1%, increased the intensity of the aluminum tungstate phase, decreased bulk density by approximately 1.32 ± 0.01 g/cm³, and increased thermal shock resistance by ensuring a loss of less than 5% of the elastic modulus after 10 cycles of thermal shock.

Effect of Free Formaldehyde on Chemical Structure and Thermal Properties of Nano-Titanium Dioxide Resin

In order to understand and improve the degradation rate of formaldehyde, the study on the chemical structure and thermal properties of nano-titanium dioxide resin by free formaldehyde was proposed. In this research, nano-titanium dioxide was prepared by the low temperature hydrolysis method and characterized by using the scanning electron microscope (SEM) and X-ray diffraction (XRD). The degradation behavior of formaldehyde was studied by using the degradation rate of formaldehyde in the container as the evaluation index. The influence of the photocatalytic coating on the degradation rate of formaldehyde under different loading conditions, different temperatures, and different humidity was investigated. The experimental results show that the formaldehyde degradation rate of the photocatalytic coating prepared by loading 5 g nano-TiO2 into a 200 g emulsion system can reach 93% under the conditions of room temperature of 25°C, humidity of 50%, and UV lamp irradiation of 120 min. Conclusion. This study is obviously better than the commercial P25 nano-titanium dioxide degradation effect of formaldehyde.

Zirconia-Alumina Composites Obtained by Centrifugal Slip Casting as Attractive Sustainable Material for Application in Construction

This paper focuses on the possibility of adapting the centrifugal slip casting method to obtain zirconia-alumina composite materials in the form of finished tube-shaped products. These types of products, due to their unique properties, can be utilised, for example, in the transport of aggressive substances, even in extreme temperatures or corrosive conditions. The study reports on the two series of zirconia-alumina composites differing in the content of ZrO₂-2.5 and 25 vol%. The fabricated and sintered materials were characterised using scanning electron microscopy (SEM), X-ray diffraction (XRD) and stereological analysis. Moreover, a life cycle assessment (LCA) was provided in accordance with the requirements of the ISO 14044 and EN 15805 standards. The obtained data clearly show that the centrifugal slip casting method allows obtaining samples with high density and extremely uniform distribution of the ZrO₂ phase in the alumina matrix. The stereological analysis results proved also that the addition of ZrO₂ is effective in reducing the growth of Al₂O₃ grains during the sintering process. The phase analysis carried out by means of XRD showed that during the sintering process, in the case of composites with a lower ZrO₂ content (2.5 vol%), the monoclinic to tetragonal transformation of ZrO₂ was total, while for samples containing 25 vol% ZrO₂, the monoclinic phase remained in a small amount in the final product.