A Study of the Effect of Sintering Conditions of Mg0.95Ni0.05Ti3 on Its Physical and Dielectric Properties

Abstract

Mg0.95Ni0.05TiO3 ceramics were prepared by traditional solid-state route using sintering temperatures between 1300 and 1425 °C and holding time of 2–8 h. The sintered samples were characterized for their phase composition, micro-crystalline structure, unit–cell constant, and dielectric properties. A two-phase combination region was identified over the entire compositional range. The effect of sintering conditions was analyzed for various properties. Both permittivity (εr) and Q factor (Qf) were sensitive to sintering temperatures and holding times, and the optimum performance was found at 1350 °C withholding time of 4 h. The temperature coefficient of resonant frequency (τf) in a range from −45.2 to −52 (ppm/°C) and unit–cell constant were not sensitive to both the sintering temperature and holding time. An optimized Q factor of 192,000 (GHz) related with a permittivity (εr) of 17.35 and a temperature coefficient (τf) of −47 (ppm/°C) was realized for the specimen sintered at 1350 °C withholding time of 4 h. For applications of 5G communication device (filter, antennas, etc.), Mg0.95Ni0.05TiO3 is considered to be a suitable candidate for substrate materials.

The Enhanced Thermal Stability of (Mg0.95Ni0.05)2TiO4 Dielectric Ceramics Modified by a Multi-Phase Method

“…However, the ratio of (Mg 0.95 Ni 0.05 )TiO 3 phase in the ceramics was decreased due to the increased grain boundary motion with the increasing sintering temperature, as shown in Table 1. Moreover, the (Mg 0.95 Ni 0.05 )TiO 3 had no noticeable impact on the dielectric properties of (Mg 0.95 Ni 0.05 ) 2 TiO 4 in our previous study [19]. Therefore, the influence of the inferior (Mg 0.95 Ni 0.05 )TiO 3 phase can be negligible when the sintering temperature is over 1350 • C. 2.…”

“…Moreover, an inferior (Mg 0.95 Ni 0.05 )TiO 3 phase also appeared during the synthesizing of (Mg 0.95 Ni 0.05 ) 2 TiO 4 , which may be attributed to the effect of the thermal decomposition mechanism [18]. However, the slight (Mg 0.95 Ni 0.05 )TiO 3 -doped (Mg 0.95 Ni 0.05 ) 2 TiO 4 possess a comparable performance, with an ε r value of 17.2, a Qf value of 180,000 GHz, and a τ f value of −45 ppm/ • C [19], compared to those of the pure (Mg 0.95 Ni 0.05 ) 2 TiO 4 composition [17].…”

Microwave Performance, Microstructure, and Crystallization of (Mg0.6Zn0.4)1−yNiyTiO3 Ilmenite Ceramics

“…Materials possessing the following dielectric properties are suitable for dielectric resonators [5][6][7][8]: (1) Permittivity (ε r ) > 20: The permittivity is an essential factor for component size reduction. (2) Quality factor (tanδ, the inverse of the dielectric loss) > 30,000 (GHz): Lower insertion loss and steeper cut-off can be obtained due to a higher Qf value, which ensured the lower dielectric loss of components.…”

“…It was reported that the partial replacement of Mg by B 2+ (B 2+ = Co, Ni, and Zn) increases the structural densification and upgrades the dielectric performance of MgTiO 3 . (Mg 0.95 B 2+ 0.05 )TiO 3 with an ilmenite-type structure has been documented to possess excellent dielectric performance [8,13,14] [22][23][24][25][26][27]. In this paper, with partial substitution of Mg 2+ (0.072 nm) by Ni 2+ (0.069 nm), the microstructure densification of (Mg 0.6 Zn 0.4 ) 0.95 Ni 0.05 TiO 3 was observed, and microwave dielectric performance of that was also further improved compared to (Mg 0.6 Zn 0.4 )TiO 3 .…”

Tunable Microwave Dielectric Properties of Ca0.6La0.8/3TiO3 and Ca0.8Sm0.4/3TiO3-Modified (Mg0.6Zn0.4)0.95Ni0.05TiO3 Ceramics with a Near-Zero Temperature Coefficient

“…To upgrade the dielectric performances of MgTiO 3 -based ceramics, some studies focus on substituting Mg with M 2+ (M 2+ = Co, Ni, and Zn) and the (Mg 0.95 M 2+ 0.05 )TiO 3 ceramics preserve the ilmenite-type structure [ 11 , 12 ]. Shen et al [ 13 ] first reported Mg 0.95 Ni 0.05 TiO 3 with a Q f of 192,000 (GHz), ε r ~17.35, and τ f of –47 (ppm/°C) for the samples sintered at 1350 °C and 4 h. The main disadvantage of (Mg 0.95 M 2+ 0.05 )TiO 3 ceramics is their high negative τ f and, hence, difficulty to be practically utilized in microwave applications. Therefore, some researchers improved the microwave dielectric properties of (Mg 0.95 M 2+ 0.05 )TiO 3 by mixing τ f compensator [ 14 ].…”