Investigating on sintering mechanism and adjustable dielectric properties of BLMT glass/Li2Zn3Ti4O12 composites for LTCC applications

Abstract A series of novel low temperature co-fired ceramics were fabricated in x BLMT-(100-x) Li 2 Zn 3 Ti 4 O 12 (2.5 ≤ x ≤ 80 wt%) composites sintered at 900 °C. The sintering mechanism, phase composition, microstructure and dielectric properties of the composites were investigated. The results showed that the sintering mechanism of composites with 3 phase was crystallized from glass beside Li 2 Zn 3 Ti 4 O 12 phase, while composites with ≥20 wt% glass were controlled by the coexistence of viscous sintering and reactive liquid-phase sintering, BLMT glass crystallized forming LaBO 3 , MgLaB 5 O 10 and a small amount of rutile phase, nevertheless, more rutile phase was formed by reacting between glass and ceramic. As BLMT glass was increased, LaBO 3 , MgLaB 5 O 10 and rutile phase gradually dominated the material and Li 2 Zn 3 Ti 4 O 12 phase decreased. Meanwhile, the dielectric constant (e r ) and quality factor (Q × f) demonstrated gradually decrease, whereas the temperature coefficient of resonant frequency (τ f ) presented a trend of fall first then rise. Typically, the composite with 60 wt% glass displayed excellent dielectric properties with e r  = 14, Q × f = 23,000 GHz, and τ f  = −3.56 ppm/°C. The corresponding fitting equations of e r , Q × f and τ f on the BLMT glass content were obtained by the Origin software, which indicated that the dielectric properties of BLMT/Li 2 Zn 3 Ti 4 O 12 composites could be precisely adjusted by adding the suitable content of glass. Therefore, the sintering process, phase composition and dielectric properties of BLMT/Li 2 Zn 3 Ti 4 O 12 composites can be controlled by varying the content of Li 2 Zn 3 Ti 4 O 12 ceramic and B 2 O 3 -La 2 O 3 -MgO-TiO 2 glass.