The preparation of Li7La3Zn2O12(LLZO) battery ceramic and its conductivity

For Li7La3Zr2O12 (LLZO) solid electrolytes, higher density usually means higher ionic conductivity. Researchers tried many preparation methods to get high density samples and at same times to realize industrial production, low cost, scalable and fast synthesis techniques. In this paper, the mainstream preparation methods of LLZO was given, as polymerized complex method, sol-gel method, field assisted sintering, combustion technique, auto-consolidation method, water-based solvent method. Among these methods, the last four methods can always increase the density to more than 93%. Especially the field assisted sintering method can make the relative density to be high as 99.8%. And all of these methods can make the ion conductivity to be higher than 1.4 × 10-4 S cm-1. Also, most of these methods introduced the Al element into LLZO to realize the liquid sintering.

Role of liquid sintering aids in the synthesis of SiAlON materials

The synthesis of dense sintered sialon with external additives selected from the system Y2O3-AlN-SiO2 is described. The highest density (3.21g/cc) was achieved at 1750ºC at 90 min of sintering with 5 wt% additive. Non-oxide ceramic materials are increasingly coming out as a potential candidate in engineering applications and among them, sialon is one of the most important materials. β-Sialon was first to be discovered in this class of compounds. It has an excellent combination of thermal, mechanical and chemical properties. The degree of sialon substitution increased with the amount of liquids, the YSiO2N crystalline phase formed concurrently. Strength degradation occurred above 1000ºC.The fracture toughness of the material sintered with a lower amount of sintering aid remained relatively unchanged to 1200ºC.

The Concurrent Sintering-Crystallization Behavior of Fluoride-Containing Wollastonite Glass-Ceramics

The fabrication of well densified wollastonite with smooth appearance by direct sintering method is still a challenge due to the competitive behaviors between sintering and crystallization. In this study, the coarser glass frits with a size of 1–4 mm are subjected to heat treatment at different temperatures. An attempt of integrating differential thermal analyzer with a slag melting temperature characteristic tester was exploited to monitor the heat and geometry changes during the heating. The results showed that the addition of CaF2 can significantly promote the crystallization of wollastonite at 940 °C, while hindering the sintering ability. At higher temperature, the increase of CaF2 acts as flux and favors the formation of eutectics, leading to a decline in the precipitation amount of wollastonite. The predominated liquid sintering brought fast shrinkage. It was found out that high content of CaF2 narrows the dense sintering temperature range and results in uneven surfaces. In order to obtain wollastonite glass-ceramics with smooth appearance, the maximum content of CaF2 in sintering glass-ceramics should be limited to 2 wt.%.

The structure of composite rollers with iron or nickel-iron base and hard surface layer of WC or TiC based hard alloy produced by the method of hot vacuum pressing with a liquid phase

In this work the structure and properties of composite rollers with surface layer made of hard alloy were studied. The rollers were made by the powder metallurgy method with sintering during pressing and the presence of a certain liquid phase during sintering (semi-liquid sintering). WC-Co and TiC-Ni-Fe materials were used as hard alloys. Iron-carbon and iron-nickel materials were used as soft base. All of the composite layers were formed in one process. The structure of base materials and border layer of these composites were studied. Investigations of thermocycling sustainability of these composite samples were carried out.