Dielectric properties of CaTiO₃ coatings prepared by plasma spraying

Abstract

This paper presents a study of dielectric properties, namely the relative permittivity and loss factor dependence on the frequency of a weak electric field. Perovskite CaTiO 3 was studied in the form of coatings and self-supporting plates made by plasma spraying. A conventional gas stabilised plasma gun (GSP) as well as a water stabilised plasma gun (WSP) were employed. It was observed that plasma sprayed titanates exhibit a strong relaxation of permittivity and loss factor decrease with a frequency rise. These properties are influenced by spray technique and spraying parameters, but the relaxation character in general is preserved in all cases. The volume resistivity of the samples was studied as well. Several aspects of the structural features of plasma deposits, especially the phase composition, porosity character, and their influence on dielectric properties are discussed.

Cubic to pseudo-cubic tetragonal phase transformation with lithium and beryllium doping in CaTiO3 and its impact on electronic and optical properties: a DFT approach

“…They are being used as a charge-storing electronic device, in moulding of ceramics, in condensers and as a major component of rocks used to confine nuclear waste [17]. Generally, CTO is used as a dielectric material but in particular, it is used as an electroceramic and ferroelectric material [18,19]. Its dielectric constant is also low and its conductivity depends upon temperature.…”

Calcium titanate (CaTiO 3 ) dielectrics prepared by plasma spray and post-deposition thermal treatment

“…10) are characteristic for purely crystalline materials; i.e. the so called amorphous phase is not observed as it was in the case of both non-annealed WSP samples [10]. (Fig.…”

“…2). For a non-annealed WSP 450 sample at 10 kHz frequency the permittivity value was 210 and for 100 Hz frequency the permittivity was about 330 [10]. Frequency dependence of as-sprayed GSP 100 sample has more or less the same character as for sintered sample.…”

“…7). Samples produced by the GSP system had better dielectric properties in a non-annealed state than non-annealed WSP samples [10].…”

“…For this study calcium titanate (CaTiO 3 ), with a tabulated relative permittivity value of 160-170 was chosen to be representative of the low-loss dielectric materials group. Previous studies on properties of plasma sprayed calcium titanate have been completed [10]. Thermal properties of plasma sprayed CaTiO 3 and mixtures of MgTiO 3 -CaTiO 3 were studied with results indicating that the thermal diffusivity of both materials decrease with increasing temperature [11].…”