# V2O5-Assisted Low-Temperature Sintering and Microwave Dielectric Properties of (1 − x)Li2.08TiO3–xLi2ZnTi3O8 (x = 0.3−0.7) Ceramics for LTCC Applications

## TL;DR

Researchers developed a ceramic material with good microwave properties that can be processed at lower temperatures, making it suitable for electronics manufacturing.

## Contribution

A new ceramic composition with V2O5 additive enables low-temperature sintering while maintaining high microwave dielectric performance.

## Key findings

- 0.6Li2.08TiO3–0.4Li2ZnTi3O8 with 0.3 wt.% V2O5 sintered at 900 °C achieves 97% density and good dielectric properties.
- V2O5 promotes liquid-phase sintering without forming secondary phases or altering permittivity.
- Ag co-firing tests confirm compatibility with Ag electrodes at 900 °C.

## Abstract

A new composite microwave–dielectric system, (1 − x)Li2.08TiO3-xLi2ZnTi3O8 (x = 0.3–0.7), was systematically investigated to identify the optimal composition for low-temperature co-fired ceramic (LTCC) applications by correlating sintering behavior, microstructural evolution, and microwave–dielectric properties. Although the undoped compositions exhibited excellent intrinsic dielectric performance, they required sintering at 1100 °C, making them incompatible with Ag-based LTCC processing. Among the investigated formulations, 0.6Li2.08TiO3–0.4Li2ZnTi3O8 was identified as the most suitable base composition. To reduce the sintering temperature, 0.3–1.0 wt.% V2O5 was introduced as a sintering aid, enabling densification at 900 °C for 30 min (97.0% relative density) while preserving the coexistence of Li2.08TiO3 and Li2ZnTi3O8 without XRD-detectable secondary phases. Microstructural observations indicated that V2O5 promoted liquid-phase sintering, leading to enhanced densification and Li2.08TiO3-selective abnormal grain coarsening without altering the intrinsic permittivity. Complementary dilatometry provided process-level evidence for this liquid-phase sintering mechanism: large total shrinkage at 900 °C (∆L/Lo≈ −17–19%), earlier Tonset/Tpeak with Tpeak lowered by ~250 °C, and an increased Rpeak, collectively supporting 900 °C/30 min as the practical firing window. The optimized 0.6Li2.08TiO3–0.4Li2ZnTi3O8 composition containing 0.3 wt.% V2O5 exhibits excellent microwave–dielectric properties (εr = 23.32, Q × f = 68,400 GHz, and τf = −1.55 ppm/°C). Higher V2O5 contents (>0.3 wt.%) caused a gradual reduction in Q × f due to increasing microstructural non-uniformity. Ag co-firing tests confirmed electrode stability with no interfacial reactions at 900 °C for 30 min. Overall, 0.3 wt.% V2O5-assisted 0.6Li2.08TiO3–0.4Li2ZnTi3O8 provides a practical sub-950 °C processing window that satisfies key LTCC requirements, including moderate permittivity, high Q × f, near-zero τf, and compatibility with Ag electrodes.