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Through a typical solid-state reaction followed by planetary ball milling, ABO3 structured perovskite Bi0.5Na0.5ZrO3 (BNZ) was employed as an additive to create the lead-free piezoceramic composite having compositional formula K0.47Na0.47Li0.06NbO3+(x)Bi0.5Na0.5ZrO3 where x = 0.0 wt% to 0.5 wt%. The prepared composites were characterized with the help of XRD, SEM, and FTIR. The XRD results indicated manifestation of morphotropic phase boundary (MPB), i.e. orthorhombic-tetragonal (O-T) phase boundary, for 0.4 wt% and 0.5 wt%. The SEM pictures revealed the microstructural properties of grain-grain size distribution and the average grain size of the composites. The elemental composition examination using EDAX revealed no foreign element contamination. The FTIR examination verified the development of perovskite, indicating that the BNZ has correctly fused into the KNLN matrix. The DC resistivity (ρdc) behavior was determined from IV and IR curves measured at room temperature together with varied temperature line up from 30 °C to 150 °C and a high dc resistivity ρdc of order ≈ 109 Ω cm was obtained for all the ceramics. The results have been analyzed and the mechanism pertaining to the results has been discussed in the paper. Thus the main idea was to develop a lead-free piezoceramic composite by incorporating Bi0.5Na0.5ZrO3 as an additive and investigating its effect on the above mentioned properties of the composite material. [ABSTRACT FROM AUTHOR]

In this paper, we studied the magnetism of Fe2N, using the ab initio and Monte Carlo studies. The magnetic moment and the exchange couplings are deduced by ab initio calculations. The obtained density of states is not symmetrical with respect to the axis of energy proving the ferromagnetic character of this compound. Any gap energy, at the Fermi level, is found confirming the metallic character of this compound. The Hamiltonian of this system consists of several physical parameters. Both the magnetic entropy and the maximum magnetic entropy are obtained. The relative cooling power and the magnetic hysteresis cycle are illustrated. The transition temperature TC value has been deduced and found to be about 252.01 K. This value is in good agreement with the experimental results presented. Also, we found that the magnetizations decrease rapidly to zero with increasing temperature. This is due to the ferromagnetic-paramagnetic phase transition caused by thermal energy. [ABSTRACT FROM AUTHOR]

In this paper, the shaft parts of failed machine tools were treated by laser cladding, and the shaft surface of 45# steel matrix was repaired. The microstructure, hardness and corrosion resistance of the cladding layer and quenched phase transformation zone were analyzed by metallographic microscope, Vickers microhardness tester, and friction and wear tester. The laser cladding layer was tested by friction and wear tester. The results showed that the friction coefficient of laser cladding layer was only 0.58, and it fluctuated slightly. The corrosion resistance of laser cladding layer was obviously increased. [ABSTRACT FROM AUTHOR]

In this paper, thick film antiferroelectric ceramics (1-x)(Pb0.97La0.02)(Zr0.46Sn0.48Ti0.06)O3-xH3BO3 ((1-x)PLZST-xH3BO3, x = 0–0.025) were prepared by solid state sintering and tape-casting method. The effects of boron-doping on the microstructure, dielectric properties and energy storage properties of (1-x)PLZST-xH3BO3 ceramics were investigated. Appropriate boron-doping can improve the stability of antiferroelectric phase, delay phase transition and increase saturation polarization strength. Compared with the undoped PLZST thick films, the maximum polarization intensity increased by 1.9 times and the residual polarization decreased by 37%. When x = 0.020, the maximum recoverable energy storage density is 2.74 J/cm3, and the energy storage efficiency is 88.12%. [ABSTRACT FROM AUTHOR]

In the present paper, Nd, Nb co-doped La2Mo2O9 system is investigated to understand phase transition, ionic conductivity and dielectric relaxation phenomenon. X-ray diffraction study confirms order-disorder phase transition by disappearance of peak splitting of (231) in co-doped LMX system, which is associated with monoclinic phase and is observed for LMX-Pure at around 2θ = 47–48°. In co-doped system, two dielectric relaxation peaks are observed, which are associated with diffusion process between O(1)-O(2) and O(1)-O(3) oxygen ion ←→ vacancies sites, while diffusion process O(1)-O(3) is supposed to be occurred in parent system having single relaxation peak. Thus dielectric relaxation phenomenon indicates phase transition is proceeding with static-to-dynamic disorder transition. Electric modulus data are revealed to ascertain correlation of relaxation dynamics and oxy-ion conductivity in co-doped LMX system. The extracted data of activation energy of oxy-ion conductivity at intermediate temperature range (500–700 °C) of co-doped samples is found relatively lower than that of the parent sample. The study reveals that incorporation of Nd, Nb co-doped in LMX system successfully suppress the phase transition and enhanced ionic conductivity at intermediate temperature range and found suitable as electrolytes for intermediate temperature solid oxide fuel cells. [ABSTRACT FROM AUTHOR]

In the present paper the phenomena predicted in [2] for substances with FE and AFE phases coexisting is experimentally shown for Pb(Mg 1/3 Nb 2/3 )O 3 and Pb(B′ 1/2 B′′ 1/2 )O 3 -type compounds. Special attention is paid to analysis of their phase diagrams. The influence of external factors on the properties of these substances is considered. It is shown that all peculiarities in the behaviour of the substances in question are described on the basis of phase transitions between FE and AFE states. [ABSTRACT FROM AUTHOR]

The phase transformation mechanism and transformation path of Cu-Ni alloys is very important to study for their applications in excellent electrical properties and chemical catalysis. In this paper, the effect of compressive strain on the transformation path and mechanism of Cu1Ni3 alloy is studied by molecular dynamics simulations. The simulation results reveal that the transformation path of alloys is from Fcc-Bcc-Hcp phase to other phase (amorphous state). The simulations not only revealed the processes of atomic displacements and pair correlation function during the transformation, but also elucidated the underlying mechanism of the transformation at the atomic level. The mechanism of phase transformation could be the lattice reconstruction caused by lattice sliding and stretching. The simulation results provide a clear landscape on the transformation mechanism, facilitating our comprehensive understanding on the phase transition in the Cu-Ni system. [ABSTRACT FROM AUTHOR]

Ferroelectric materials with high Curie temperatures, TC, and tuning of the TC over a large temperature range are very important for the basic sciences and engineering. This paper reviews the various types of high-temperature ferroelectrics with perovskite, bismuth layered, tungsten bronze, and perovskite slab structures, especially Sr2Nb2O7 with TC = 1342 °C and its family. The lattice instability of the high-temperature ferroelectric phase transitions is also discussed. The superior tunability of the TC is achieved by the substitution of cations at the A- and B-sites in the perovskite-like structures. The variation of the soft optic and relaxation modes and elastic anomalies related to structural phase transitions were discussed in relation to the A- and B-site substitutions of oxygen octahedral ferroelectrics, especially Ba2NaNb5(1-x)Ta5xO15 with a tungsten bronze structure and (BaxSr1-x)2Nb2O7, Sr2(Nb1-xTax)2O7 with the perovskite slab structure. [ABSTRACT FROM AUTHOR]

In this paper, the development in the field of ferroelectrics is reviewed by summarizing the topics in the field as presented at the International and European conferences on Ferroelectrics. While from the very beginning in 1966 until now fundamentals in ferroelectrics always played a significant role, it is shown that the topics considerably broadened over the years and are nowadays barely overlooked. Polarity dominated the field from the beginning; however, now its combination with more exotic properties like skyrmions, magnetism, functional domain walls has entered the stage and substantially enlarge the field of applications. [ABSTRACT FROM AUTHOR]

In the present paper the phenomena predicted in [1] for substances with coexisting FE and AFE phases coexistence is experimentally shown. The examples of PZT-based solid solutions are investigated. The solid solutions for which FE and AFE states have equal or close energy stability possess the following experimental properties: - a high degree of (paraelectric) PE phase transition diffuseness; - an essential dispersion of permittivity in the region of diffuse maximum of the dependences ℇ′(T) and ℇ′′(T) and fulfilment of the Fogel-Fülcher law; - an increase of the measuring AC field amplitude E 0 leads to a linear decrease of T′ m and to an increase of ℇ′(T′ m ); the tangent of T′ m (E 0 ) dependence decreases with an increase of AC field frequency; - the presence of effects which point to the existence of polar phase domains at temperatures essentially higher than T′ m and T′′ m ; - dependence of their properties on the sample's history; - a long-duration relaxation. [ABSTRACT FROM AUTHOR]