Impact-Induced Reaction Characteristic and the Enhanced Sensitivity of PTFE/Al/Bi2O3 Composites

In this paper, the reaction characteristic of a novel reactive material, which introduced bismuth trioxide (Bi2O3) into traditional polytetrafluoroethylene/aluminum (PTFE/Al), is studied. The effect of Bi2O3 with different content and particle size on the reaction behaviors of PTFE/Al/Bi2O3 are investigated by drop-weight test and X-ray diffractometer (XRD), including impact sensitivity, energy release performance under a certain impact, and reaction mechanism. The experimental results show that the content of Bi2O3 increased from 0% to 35.616%, the characteristic drop height of impact sensitivity (H50) of PTFE/Al/Bi2O3 reactive materials decreased first and then increased, and the minimum H50 of all types of materials in the experiment is 0.74 times that of PTFE/Al, and the particle size of Bi2O3 affects the rate of H50 change with Bi2O3 content. Besides, with the increase of Bi2O3 content, both the reaction intensity and duration first increase and then decrease, and there is optimum content of Bi2O3 maximizing the reaction degree of the PTFE/Al/Bi2O3. Furthermore, a prediction model for the impact sensitivity of PTFE-based reactive material is developed. The main reaction products include AlF3, xBi2O3·Al2O3, and Bi.

Effect of Bi2O3 content on the microstructure and electrical properties of SrBi2Nb2O9 piezoelectric ceramics

Lead-free ceramics, SrBi2Nb2O9–xBi2O3 (SBN–xBi), with different Bi contents of which the molar ratio, n(Sr) : n(Bi) : n(Nb), is 1 : 2(1 + x/2) : 2 (x = −0.05, 0.0, 0.05, 0.10), were prepared by conventional solid-state reaction method.

Synthesis and Characterization of B2O3Additive on Ni-Cu-Zn ferrites by Solid State Reaction Method

Ni-Cu-Zn ferrites are well-known technological magnetic materials used for manufacturing of multilayer chip inductor and applications in various electrical devices. The work is focused on the persuade of substitutions and sintering additive B2O3 on structural, transport and electromagnetic properties of Ni-Cu-Zn ferrites. The composition Ni0.28Cu0.10Zn0.62Fe2O4 + x wt. % where x= 0.2 to 0.8 for V2O5 was prepared by using the solid state reaction technique sintered at 1200oC with 6 hours holding time. Lattice parameters of Ni0.28Cu0.10Zn0.62Fe2O4 + x wt. % Bi2O3 are slightly decrease with increase x content. The grain growth by increasing the additives Bi2O3 content inter diffusion as results after > 0.4wt. % Bi2O3 content abnormal grain growth. Curie temperature (Tc) decreases continuously with increase of doped Bi2O3 additives in ferrite samples. The magnetization process all the samples are soft magnetic behavior of magnetic materials. Initial permeability (µi) decreases with increasing doped Bi2O3 content in ferrite samples and hence the highest value of quality factor is found for x = 0.4 within the range 20 kHz to 2MHz. The µi shows the flat profile from 1 kHz to 4MHz indicating frequency stability for all the ferrite samples. The visible grain growth indicates the improved electromagnetic properties. DC resistivity decreases with increasing temperature shows the semiconducting nature of the sample. With increasing the frequency, the dielectric constant is found to decrease continuously and remain almost frequency independent at higher frequency range.

Influence of Bismuth Content on Complex Immittance Characteristics of Pressureless Sintered BiNbO4 Ceramics

Goal of the present research was to study immittance properties of BiNbO4 ceramics fabricated by the solid state reaction route followed by pressureless sintering. Four sets of samples were examined, namely the one fabricated from the stoichiometric mixture of oxides, viz. Bi2O3 and Nb2O5 as well as the ones with an excess of 3%, 5% and 10% by mole of Bi2O3. The immittance properties were studied by impedance spectroscopy. Measurements were carried out within the frequency range ν =20Hz-1MHz and temperature range T =RT-550°C. The Kramers-Kronig data validation test was employed in the impedance data analysis. It was found that complex impedance first increases with an increase in Bi2O3 content and decreases for 10mol% excess of Bi2O3. Two relaxation phenomena manifested themselves at elevated temperature (T>267°C) within the measuring frequency range. The conductivity relaxation phenomenon (M″(ν) spectra) took place at higher frequency than the phenomenon with dominant resistive component (Z″(ν) spectra).