Realizing translucency in aluminosilicate glass at ultralow temperature via cold sintering process

Abstract

Glass with high visible-light transparency is widely considered as the most important optical material, which typically requires a processing temperature higher than 1000 °C. Here, we report a translucent aluminosilicate glass that can be prepared by cold sintering process (CSP) at merely 300 °C. After eliminating structural pores in hexagonal faujasite (EMT)-type zeolite by heat treatment, the obtained highly active nanoparticles are consolidated to have nearly full density by adding NaOH solution as liquid aids. However, direct densification of EMT powder cannot remove the structural pores of zeolite completely, leading to an opaque compact after the CSP. It is proved that the chemical reaction between the NaOH- and zeolite-derived powders is highly beneficial to dissolution-precipitation process during sintering, leading to the ultra-low activation energy of 27.13 kJ/mol. Although the addition of 5 M NaOH solution greatly promotes the densification via the reaction with aluminosilicate powder, lower or higher concentration of solvent can deteriorate the transmittance of glass. Additionally, the CSP-prepared glass exhibits a Vickers hardness of 4.3 GPa, reaching 60% of the reported value for spark plasma sintering (SPS)-prepared sample.

Water and SnF2 Assisted Ultralow-Temperature Sintering of Mechanically Tough Y3Fe5O12 Composites for Magneto-Dielectric Antennas

“…As the volume fraction of SnF 2 increases, it may increase the grain growth and the particle–particle contact, which results in high density as well as strength of the composites. The 0.5YIG–0.5SnF 2 composite shows the highest microhardness of around 4.7 GPa, which is comparable to the widely used sintered ceramics such as Al 2 O 3 obtained through different synthesis and sintering methods (reported hardness varies between 4.3 and 18 GPa) and also with the other cold-sintered composites such as aluminosilicate glass, which possess a hardness of 4.3GPa. − …”

Hybrid low‐temperature sintering processes of electro‐ceramics

“…At present, CSP has successfully applied in microwave dielectric, ferroelectric, piezoelectric, target material, lithium battery, thermoelectric, and optical material. 25,[37][38][39][40][41][42] It is demonstrated that CSP can be combined with other sintering methods, so as to improve the sintering efficiency. Gonzalez-Julian et al have successfully combined CSP with FAST/SPS technology to prepared dense ZnO ceramics at 250 • C with relative densities higher than 90%.…”

Effect of Surface Dispersion of Fe Nanoparticles on the Room-Temperature Flash Sintering Behavior of 3YSZ

“…It is different from spark plasma sintering (SPS) or other field-assisted sintering technology (FAST) in that the furnace temperature is lower (usually lower than 1000 °C), the sintering time is shorter (a few seconds), and the electric current flows through the ceramic to generate Joule heat [ 2 , 3 ]. As an energy-saving and cost-efficient sintering method [ 4 , 5 , 6 , 7 ], it requires no external heating and can be conducted at room temperature. Surface flashover can activate the room-temperature flash sintering of ceramics such as ZnO [ 8 ] and yttria-stabilized zirconia (YSZ) [ 9 ].…”