Preparation of fine-grained Li4SiO4 pebbles by a combined sol–gel and hydrothermal method and their thermal cycling behavior

Li4SiO4 has been regarded as the vigorous competitors for tritium breeding materials due to its distinct advantages. In this work, Fine-grained Li4SiO4 pebbles were prepared by a combined sol–gel and hydrothermal method (SG–H method). According to our researches, hydrothermal treatment was helpful to gain the ultrafine powders, and two-step sintering process showed obvious advantages in the preparation of fine-grained Li4SiO4 pebbles. The related physical parameters of the samples were measured. Afterwards, thermal cycling tests were carried out to study the microstructure evolution and the variation of crushing load. SEM analyses and compression tests results indicated the Li4SiO4 pebbles obtained by SG–H method exhibited favorable stability under thermal cycling. It suggested that the obtained Li4SiO4 pebbles might meet the requirement of high service temperature in fusion reactor blanket. •A combined sol–gel and hydrothermal method was proposed to prepare Li4SiO4 pebbles.•Hydrothermal treatment contributes to obtain high-quality gels and ultrafine powders.•The fine-grained Li4SiO4 pebbles exhibit favorable stability under thermal cycling.•The obtained Li4SiO4 pebbles have high purity, good sphericity and small grain size.