Dimensional change behavior of porous MgTi 2 O 5 in reactive sintering

Abstract

Volume-shrinkage of a sample in reactive sintering generally tends to be larger than that in conventional sintering. New techniques to suppress the volume shrinkage are eagerly needed for actual manufacturing. Recently, we have reported that reactively sintered porous MgTi2O5 from hydromagnesite and TiO2 rutile showed less volume shrinkage than that from hydromagnesite and TiO2 anatase. The result demonstrated that the compositional control of starting polymorphs can be a potential technique to optimize the volume shrinkage. In this paper, in order to evolve the reactive sintering technique, volume-changes during reactive sintering were dynamically monitored by thermomechanical analysis (TMA). The dimensional change behavior measured by TMA was linked up with the reaction behavior clarified by high-temperature X-ray diffraction (HT-XRD). In dilatometry curves, transient volume expansions were observed and they were well-explained by the formation and crystal growth of intermediate MgTiO3 and objective MgTi2O5 particles.

Single crystal growth of CoTi2O5 by solid state reaction synthesis

“…CoTi 2 O 5 has been observed to be antiferromagnetic 23 with possible applications in magnetic sensors, and has been studied as a photocatalyst, 24 but other properties are largely unexplored. However, the isostructural phases Al 2 TiO 5 and MgTi 2 O 5 are known for their low thermal conductivity and low thermal expansion, [25][26][27][28][29] and have applications where thermal insulation and thermal shock resistance are required such as in combustion engines [30][31][32][33] and catalyst carriers. [34][35][36] A primary drawback for these materials is their strong anisotropy of thermal expansion, which leads to poor strength due to extensive microcracking.…”

Spherical porous granules in MgO Fe2O3Nb2O5 system: In situ observation of formation behavior using high-temperature confocal laser-scanning microscopy

“…6) that some SPGs by furnace heating (not by the in situ observation) had the diameter of ~150 m, which implies the size shrinkage under the slower heating rate became milder. Formation of the 3-D network structure may result in such mild shrinkage (or even expansion) during the heating [24].…”

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

“…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 .…”