Towards Ultra-Tough Oxide Glasses with Heterogeneities by Consolidation of Nanoparticles

We prepared heterogeneous alumina-silicate glasses by consolidating nanoparticles using molecular dynamics simulations. Consolidated glasses from either low alumina content alumina-silicate glasses or high alumina content alumina-silicate glasses show significantly improved ductility around consolidation pressure of ~3 GPa. The introduced structural heterogeneities, namely over-coordinated network formers and their neighboring oxygen atoms, are identified as plasticity carriers due to their high rearrangement propensity. In addition, consolidated oxide glass from both 23.4Al2O376.6SiO2 and 73.1Al2O326.9SiO2 nanoparticles show improved flow strength (up to 1 GPa) due to the introduction of chemical heterogeneities. Last but not least, apparent hardening behavior appears upon cold work in consolidated glasses, with an increase of yield strength from ~3.3 GPa to ~6.4 GPa. This method is a big advancement toward ultra-strong and ultra-tough glasses by breaking the structure, composition and size limitations in traditional melt-quench process.

Methods to Improve the Quality of Ceramic Products

This article presents the results of experimental studies aimed at improving the physicomechanical properties of effective hollow ceramic stones using various technological methods that will disperse, homogenize and structure the ceramic mixture by introducing industrial waste with high alumina content, dispersed reinforcement, and also mechanical activation of the molding material, accompanied by the fragmentation of clay particles to a colloidal degree of dispersion, allows eliminating the aging process. The main molding characteristics of the investigated mixtures were determined, X-ray phase analysis of ceramic masses and a shard of the control composition was performed and after dispersion, activation modes were worked out, strength characteristics of ceramic samples made of dispersed clay raw materials were determined.

Interface Reaction between Nd2O3 and Alumina Single Crystal

A kind of high alumina content ceramic stand wear and tear has been designed. The interface chemical reaction between single crystal alumina (in order to eliminate the influence of grain boundaries) and Nd2O3 powder has been observed. Microstructure and wear rate of the ceramic were investigated by SEM and by a purposely designed experimental device for the measurement of wear rate. Perimental results showed that a rare earth aluminate formed on the interface and the wear rate of a sample has reduced by 34%. The newly formed compound and single crystal alumina formed a compact structure which could make the grain boundaries strengthened and also lead to a beneficial effect on the elimination of pore and the density of the ceramic, at the same time improve abrasive resistance.

The Preparation of High Alumina Content Alumina Sol

The alumina sol with high content of Al2O3 was prepared by peptizing aluminum hydroxide powder. The properties of the alumina sol were characterized by Fourier transform-infrared (FT-IR) spectrum, zeta potential analyzer, X-ray diffraction (XRD) and Transmission electron microscope (TEM). The results show that the sol with high content of Al2O3 can be easily prepared by peptizing the soluble aluminum hydroxide powder, the smaller of the size of aluminum hydroxide powder, the higher of the aluminum content of the alumina sol. Two-step peptization process is optimum, the effect of peptization aluminum hydroxide powder using AlCl3 :HCl=1:4 solution as peptizer is best, the alumina sol sample with pH value of 2.5 and alumina content 11% had good stability. A great application potential of the high alumina content sol has been displayed in preparing FCC catalysts.