Abstract:
In modern materials science, a considerable amount of research is focused on obtaining new ceramic
materials to create efficient functional elements. Acquiring highly efficient and stable ceramic catalysts
for alternative energy is an important task that demands an urgent solution. Solving this problem as
fast as possible is essential, as it will facilitate the development of new technologies that can prevent
future energy crises. Nickel oxide (NiO) and spinel with the composition NiAl2O4 are excellent
candidates as high temperature catalysts used in alternative energy applications. This paper studies the
synthesis of NiO/NiAl2O4 composite ceramics and the effect of high-temperature aging on their phase
composition, crystalline properties, and dielectric characteristics. The study found that the phase
composition and microstructure of the ceramics remain unchanged after several thermal aging cycles
at 700 °C. However, the crystalline parameters and low-frequency dielectric characteristics may
fluctuate significantly depending on the duration of aging. The observed variations were
predominantly influenced by the microstructural features of the composite ceramics. As the average
grain size increased and the phase transformations were completed, the crystalline parameters and
low-frequency dielectric characteristics reached a stable state without further alteration. For
NiO/NiAl2O4 ceramics with a sintering temperature of 1500 °C, the highest shrinkage, low dielectric
loss values and acceptable hardness were observed, indicating that the fabricated ceramics are suitable
for mechanical processing. In general, the obtained composite ceramics show high temperature
stability and are well-suited for use as functional elements in hydrogen energy applications.
