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LaNbO4 ceramics with NiO/CoO addition were designedly prepared through the conventional solid-state reaction. Compared with the pure LaNbO4 ceramics, attractively lower sintering temperatures and better microwave dielectric properties had been reached in the additive samples. The sintering behavior of the additive ceramics were characterized by the densities. For phase composition of LaNbO4-NiO/CoO ceramics, two phases were indexed as monoclinic fergusonite structure of LaNbO4 and isometric structure of NiO/CoO separately. The dielectric constants of LaNbO4-NiO/CoO ceramics had been analyzed by densities and polarizability. The quality factors (Q×f values) could be distinctly optimized to 95,050 GHz by NiO addition and 62,100 GHz by CoO addition, respectively. Moreover, intrinsic and extrinsic factors on the Q×f values had been further discussed relying on Raman spectrum and grain size analysis, with grain size (which refer to the extrinsic factors) being consequently verified to play the dominant role.

New microwave dielectric ceramics of Mg2LaNbO6, which had high quality factors (Q׃) and near-zero frequency temperature coefficient, were synthesized via conventional solid-state reaction. The sintering characteristic, crystal structure and microwave dielectric properties of Mg2LaNbO6 ceramics were characterized and investigated. As a result, Mg2LaNbO6 ceramics had a complex phase composition: LaNbO4 and MgO as the main and the second phase respectively, with an unknown phase (which related to the MgO) being detected. Well-developed micro-structures of Mg2LaNbO6 ceramics were obtained in the designed sintering temperature zone, with the grain size and its distribution also being investigated. Moreover, the permittivity, which was related to the density, remained almost unchanged. The Q׃ values increased first and then decreased, which was governed by the grain size and its distribution. Additionally, the τf values of Mg2LaNbO6 ceramics was relatively stable and near to zero.

The Mg-based hydrogen storage alloy Mg 2− x Al x Ni (0≤ x ≤0.5) have been successfully synthesized by a diffusion method (DM). The structures of these alloys have been examined by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Electrochemical characteristics have also been investigated, such as corrosion resistance and electrochemical capacity. It is found that a new phase appears when Al is added to the Mg–Ni system. It can be observed that there are a large number of defects on the alloy surface, which strongly affect its characteristics. The electrochemical capacity and cycle lives of Al-containing alloys increase strongly compared to the Al-free alloy. With increasing Al concentration in the alloys, the capacity also increases due to the increase of the amount of the new phase.