scholarly journals Structure and properties of nanocrystalline tetragonal BaTiO3 prepared by combustion solid state synthesis

2020 ◽  
Vol 52 (3) ◽  
pp. 257-268
Author(s):  
S. Filipovic ◽  
Lj. Andjelkovic ◽  
D. Jeremic ◽  
P. Vulic ◽  
A.S. Nikolic ◽  
...  

Barium titanate (BaTiO3) attracts high scientific and technological attention due to good dielectric and electromechanical properties. Although BaTiO3 is one of the most frequently investigated ferroelectric materials, the need for finding new and/or improved synthesis methods of this material still exists. In this paper, a novel, mild synthesis route for producing tetragonal BaTiO3 from barium nitrate and Ti-oxalate precursor is presented. Morphology of the prepared and subsequently sintered BaTiO3 was determined by SEM. Particle size distribution of the as prepared powder was monitored by the laser diffraction. The phase composition, structure and lattice dynamics were investigated by XRD and Raman spectroscopy. Finally, dielectric parameters were determined in the temperature range from 30 to 180?C, and within a variety of frequencies. Curie temperature was detected at 130?C.

2017 ◽  
Vol 62 (2) ◽  
pp. 691-696
Author(s):  
B. Wodecka-Dus ◽  
L. Kozielski ◽  
J. Erhart ◽  
M. Pawełczyk ◽  
D. Radoszewska ◽  
...  

AbstractEffects of La3+admixture in barium lanthanum titanate (BLT) ceramics system with colossal permittivity on performance of prospective piezoelectric cold plasma application were studied. Usage of cold atmospheric pressure plasma appears promising in terms of industrial and healthcare applications. Performed investigation provide consistent evaluation of doping lanthanum amount on piezoelectric coefficients values with simultaneous capability of charge accumulation for effective plasma generation. Modification of ferroelectric materials with heterovalent ions, however with the lower radii than the original atoms, significantly affects their domain mobility and consequently electromechanical properties. To determine the piezoelectric coefficients, the resonance-antiresonance method was implemented, and values of piezoelectric and dielectric parameters were recorded. Finally the results indicated that addition of 0.4 mol.% of La3+ions to the ceramic structure maximally increased the values of piezoelectric coefficient tod33= 20 pC/N and to huge dielectric constant toε33T= 29277.


2020 ◽  
pp. 234-240
Author(s):  
V.A. Levchenko ◽  
Yu.V. Panfilov

Tendency of strengthening coatings on cutting tools processes evolution is analyzed. Manifold of strengthening materials, strengthening coatings deposition methods, process and analytical equipment for coatings manufacture and measurement of it’s properties is described. International standards for strengthening coatings on cutting tools composition, structure and properties are presented.


Author(s):  
T. I. Bobkova ◽  
B. V. Farmakovsky ◽  
N. A. Sokolova

The work deals with topical issues such as development of composite nanostructured powder materials. The results of creating powders based on the system “aluminum–nitride of silicon” are presented. Complex investigations of the composition, structure and properties of powder materials, as well as coatings formed on their basis by supersonic cold gas dynamic spraying, were carried out. It has been found that the high-energy treatment of a powder mixture of aluminum with nanofibers of silicon nitride provides the formation of a composite powder in which a new phase of the Si(1-х)AlхO(1-х)Nх type is formed, which additionally increases the hardness in the coatings to be sprayed.


2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Jinlong Jiang ◽  
Qiong Wang ◽  
Yubao Wang ◽  
Zhang Xia ◽  
Hua Yang ◽  
...  

The titanium- and silicon-codoped a-C:H films were prepared at different applied bias voltage by magnetron sputtering TiSi target in argon and methane mixture atmosphere. The influence of the applied bias voltage on the composition, surface morphology, structure, and mechanical properties of the films was investigated by XPS, AFM, Raman, FTIR spectroscopy, and nanoindenter. The tribological properties of the films were characterized on an UMT-2MT tribometer. The results demonstrated that the film became smoother and denser with increasing the applied bias voltage up to −200 V, whereas surface roughness increased due to the enhancement of ion bombardment as the applied bias voltage further increased. The sp3carbon fraction in the films monotonously decreased with increasing the applied bias voltage. The film exhibited moderate hardness and the superior tribological properties at the applied bias voltage of −100 V. The tribological behaviors are correlated to the H/E or H3/E2ratio of the films.


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