Fabrication of submicron Li‐rich Li₂(Ti,Zr)O₃ solid solution ceramics with sluggish grain growth rate

Abstract

Doping and forming solid solution is an effective approach to tailor densification and grain growth. In this study, submicron Li2(Ti,Zr)O3 solid solution ceramics was successfully fabricated by a modified solid‐state route for the first time. The use of appropriate starting powders can greatly reduce the synthesis temperature, and the preparation of Li2(Ti,Zr)O3 with submicron grain size is possible. The substitution of Ti by Zr will inhibit the phase transition from cubic to monoclinic structure, as well as the grain growth and pore removal. By doping 10‐at.% Zr, the grain size was significantly decreased from several μm to 400 nm at 900°C, which contributes to a high conductivity eight times that of pure Li2TiO3. Moreover, after being heated at 900°C for 10 days, the grain size of Li2(Ti,Zr)O3 only increases to 5 μm; however, the grains of Li2TiO3 grows up to 16 μm with abnormal grain growth. The compositions of Li2(Ti,Zr)O3 are high uniform with no element segregation, indicating the sluggish grain growth rate is caused by the slow diffusion of Zr rather than segregation‐induced solute drag. By adding excess Li and two‐step sintering, the Li‐rich Li2(Ti,Zr)O3 ceramic pebbles with high crush load of 50–60 N and small grain size of 300–500 nm were successfully fabricated. This work demonstrates a simple method for the synthesis of Li2(Ti,Zr)O3, which makes this material more widely accessible for exploration and also help accelerate its engineering application to be an advanced solid breeder.

One‐step fabrication of Li2TiO3 ceramic pebbles using pulsed YAG laser

“…These values were low compared with the Li 2 TiO 3 pebbles fabricated by the other methods and similar to those of Li 4 SiO 4 -Li 2 TiO 3 biphasic pebbles fabricated by melt process; the crush loads of Li 2 TiO 3 pebbles by emulsion method, 34 Li 2 TiO 3 pebbles by piezoelectric microdroplet jetting, 11 Li-rich Li 2 TiO 3 pebbles by rolling method, 35 and Li 4 SiO 4 -Li 2 TiO 3 pebbles by melt process 24 are 37.2, 25.7, 10-41, and 5-15 N. Crush load of the pebbles could be improved by an additional heat treatment and/or compositional modification, as reported in the previous studies. 22,36 Particularly, an addition of Li 2 CO 3 to the initial powder as a sintering aid may contribute both to densification and increase of Li/Ti ratio. 37 F I G U R E 4 Size distributions of the pebbles fabricated with the laser powers of 6.9 J (A), 7.9 J (B), 9.0 J (C), and 9.8 J (D).…”