Destruction phenomena in ferroactive materials

Abstract

The results of a comprehensive study of the crystal structure, grain structure, and strength properties of ceramic bismuth ferrite with rare earth elements (REE) obtained by two-stage solid-phase synthesis followed by sintering using conventional ceramic technology are presented. The reasons for the formation of low mechanical strength and the development of destruction phenomena in solid solutions with small REE ([Formula: see text] Å) are considered: Tb, Dy, Ho, Er, Tm, Yb, Lu. The causes of the observed phenomena associated with the composite-like structure of the studied media and, as a consequence, the occurrence of local stresses of structural elements that provoke crack formation are established. A source of the latter are also the structural features of the grain landscape. The conclusion is made about the appropriateness of taking into account the information obtained when developing devices based on BiFeO3/REE multiferroics.

Microwave Absorption Properties of Ceramics Based on BiFeO3 Modified with Ho

“…Bi 1-x Ho x FeO 3 samples with x = 0.00-0.20 and ∆x = 0.05 contain two impurity phases Bi 25 FeO 40 and Bi 2 Fe 4 O 9 , and relative density (ρ rel ) is in the range 83.78-88.33 depending on x. The work [13] present the results of previous studies. Figure 6 show X-ray diffraction patterns of Bi 1−x Ho x FeO 3 SS with x = 0.30-0.50.…”

“…= 1200 K (x = 0.15, 0.20), τ sint. = 1.5 h (Table 1) [13]. Mechanical activation (MA) of synthesized SS powders with x = 0.30-0.50 was carried out at the stage of production of press powders prepared for sintering.…”

“…Table 1. Phase composition and optimal conditions of SS ceramics (Bi 1−x Ho x )FeO 3 [13]. Tables 2 and 3 show the process of optimizing the conditions for obtaining the SS of the Bi 1−x Ho x FeO 3 system with x = 0.30-0.50.…”

Overview: State-of-the-Art in the Energy Harvesting Based on Piezoelectric Devices for Last Decade

“…However, 33-mode [77][78][79][80] and 31-mode [81][82][83] are applicable to most piezoelectric energy harvesters. The problem of estimation of the effectiveness of piezoelectric material used and developed can be considered on the example of works [84,85]. These authors present methods for measuring the output characteristics (voltage and power) of devices, as well as the parameters of piezomaterials with promise electrophysical and mechanical properties.…”

“…The use of CMC technology can significantly improve the mechanical properties of ceramic materials. However, the problem of compromise of properties, that is, deterioration of electromechanical properties with an increase in the content of the passive phase, remains unresolved [85,134]. An interesting solution, proposed in recent years to improve both electrophysical and mechanical properties, is the development of piezoceramic materials with metallized pore surfaces [135][136][137].…”