Rare Earth and Perovskite Composite Ceramics Applied for the Thermistor with Wide Temperature Range

2012 ◽  
Vol 512-515 ◽  
pp. 613-616 ◽  
Author(s):  
Bo Zhang ◽  
Qing Zhao ◽  
Ai Min Chang ◽  
Peng Jun Zhao ◽  
Fang Guan
Keyword(s):  
Wide Temperature Range ◽  
Perovskite Phase ◽  
Temperature Characteristic ◽  
Absolute Temperature ◽  
Composite Ceramics ◽  
Conventional Solid State Reaction ◽  
Temperature Range ◽  
Air Atmosphere ◽  
Wide Range ◽  
Ntc Thermistors

Different compositions (aY2O3+bCeO2)-0.4YCr0.5Mn0.5O3 (a+b=0.6) were prepared via a conventional solid-state reaction at 1200°C, and sintered under air atmosphere at 1600°C. XRD patterns analysis has revealed that for 0<a<0.6, the major phases present in the calcined bodies are Y2O3, CeO2 and orthorhombic perovskite YCr0.5Mn0.5O3 phase, respectively. SEM and EDAX observations confirm the obtaining of three-phased composite ceramics. The brighter regions are the Y2O3 and CeO2 phase, whereas the darker are perovskite phase. All the NTC thermistors prepared show a similar linear relationship between the ln of the resistance and the reciprocal of the absolute temperature, indicative of NTC characteristics. For 0≤a≤0.6, the plotting curves of resistance- temperature characteristic are none linear on the wide temperature range, exhibit two branches. The obtained B25/150 and B700/1000 constants of the thermistors are in the range 3600-4400K and 6700-12000K. The magnitude order of the resistivity at 25°C is of 106-107Ωcm and activation energies vary from 0.313 to 1.029 eV at low and high temperatures, respectively. These compounds, having good NTC characteristics in a wide range of temperatures, could be applied as potential candidates for NTC thermistors from ambient to 1100°C.

Enabling highly reversible sodium metal cycling across a wide temperature range with dual-salt electrolytes

2021 ◽  
Author(s):  
Akila C. Thenuwara ◽  
Pralav P. Shetty ◽  
Neha Kondekar ◽  
Chuanlong Wang ◽  
Weiyang Li ◽  
...  
Keyword(s):  
Wide Temperature Range ◽  
High Energy ◽  
Liquid Electrolyte ◽  
Metal Cycling ◽  
Temperature Range ◽  
Sodium Metal ◽  
Wide Range

A new dual-salt liquid electrolyte is developed that enables the reversible operation of high-energy sodium-metal-based batteries over a wide range of temperatures down to −50 °C.

Prediction of Fracture Toughness Temperature Dependence Over a Wide Temperature Range Using Simplified and Direct Scaling Method

2018 ◽  
Author(s):  
Takashi Inoue ◽  
Toshiyuki Meshii
Keyword(s):  
Fracture Toughness ◽  
Temperature Dependence ◽  
Yield Stress ◽  
Wide Temperature Range ◽  
Fracture Load ◽  
Specimen Thickness ◽  
Temperature Range ◽  
Direct Scaling ◽  
Wide Range ◽  
Mc Method

The fracture toughness KJc of the material in the ductile to brittle transition temperature (DBTT) range exhibits both test specimen thickness (TST) dependence and temperature dependence. Attention has been paid to the master curve (MC) method, which provides an engineering approach to address these two issues. Although MC is intended to be applied to arbitrary ferritic material whose yield stress is within the range of 275 to 825 MPa, the KJc value must be obtained to determine the material dependent reference temperature T0. The applicable range of MC method is restricted to T0 ± 50 °C. Previous studies indicate that additional pre-tests to obtain T0 are necessary; thus, there might be some unwritten requirement to the test temperature for the KJc temperature dependence prediction in MC method to work effectively. If testing must be conducted for the material of interest at some restricted temperature, a more flexible KJc temperature dependence prediction can possibly be obtained for a wide temperature range in the DBTT range, if the simplified and direct scaling (SDS) method, which predicts fracture “load” from yield stress temperature dependence proposed previously is applied. In this study, the SDS method was applied to two different steels: Cr-Mo steel JIS SCM440 and 0.55% carbon steel JIS S55C. Both tensile and fracture toughness tests were performed over a wide range of temperatures, specifically, −166 to 100 °C for SCM440 and −166 to 20 °C for S55C. The SDS method (i.e., fracture load is proportional to 1/(yield stress)) was initially validated for the specimens in the DBTT range. Finally, a simplified method was proposed and initially validated to predict the KJc temperature dependence, by applying the SDS using the EPRI plastic J functional form.

scholarly journals Electrical characteristics of Er doped BaTiO3 ceramics

2017 ◽  
Vol 49 (2) ◽  
pp. 129-137 ◽  
Author(s):  
Vesna Paunovic ◽  
Vojislav Mitic ◽  
Milos Djordjevic ◽  
Milos Marjanovic ◽  
Ljubisa Kocic
Keyword(s):  
Electrical Resistivity ◽  
Temperature Response ◽  
Sem Analysis ◽  
Electrical Characteristics ◽  
Conventional Solid State Reaction ◽  
Homogeneous Microstructure ◽  
Temperature Range ◽  
Grain Sizes ◽  
Air Atmosphere ◽  
Er Doped

In this study, the electrical resistivity (?) and PTC effect of Er doped BaTiO3 ceramics are investigated. The concentrations of Er2O3 in the doped samples vary from 0.01 to 1.0 at% Er. The samples are prepared by the conventional solid state reaction, and sintered at 1320? and 1350?C in air atmosphere for 4 hours. The SEM analysis shows that all of measured samples are characterized by polygonal grains. The uniform and homogeneous microstructure with grain sizes from 20 to 45?m is the main characteristic of the low doped samples (0.01 and 0.1 at% Er). For the samples doped with the higher dopant concentration (0.5 and 1.0 at%) the average grains sizes have been ranged from 5 to 10 ?m. The electrical resistivity is measured in the temperature range from 25?C to 170?C, at frequencies 1 kHz, 10 kHz and 100 kHz. The electrical resistivity values, measured at frequency of 1 kHz and room temperature, have been ranged from 1.62?104 ?cm to 4.24?104 ?cm, for samples sintered at 1320?C and from 1.43?104 ?cm to 1.94?104 ?cm, for samples sintered at 1350?C. A nearly flat and stable electrical resistivity-temperature response is characteristic for all samples at the temperature range from 25?C to 120?C. Above this temperature, the electrical resistivity increases rapidly. At 170?C the value of electrical resistivity is ranged 9.84?104 ?cm -1.62?105 ?cm, for Tsin=1320?C, and 6.11?104 ?cm 1.32?105 ?cm, for Tsin=1350?C. The electrical resistivity decreases with concentration increment up to 0.5 at%, while above 0.5 at% it increases. Also, with increasing frequency, ? decreases for a few orders of magnitude.

scholarly journals Interfacial properties of the ionic liquid [bmim][triflate] over a wide range of temperatures

RSC Advances ◽  
2018 ◽  
Vol 8 (18) ◽  
pp. 10115-10123 ◽  
Author(s):  
José L. Rivera ◽  
Luis Molina-Rodríguez ◽  
Mariana Ramos-Estrada ◽  
Pedro Navarro-Santos ◽  
Enrique Lima
Keyword(s):  
Surface Tension ◽  
Ionic Liquid ◽  
Wide Temperature Range ◽  
Interfacial Properties ◽  
Liquid Density ◽  
Tension Zone ◽  
Temperature Range ◽  
Linear Behavior ◽  
Vacuum Interface ◽  
Wide Range

Picture of the ionic liquid [bmim][triflate] at the vapor/vacuum interface. The liquid density and surface tension show linear behavior in a wide temperature range. The outer interfacial space shows a zero-surface tension zone.

Electrical properties of thin-film resistors in a wide temperature range

Circuit World ◽  
2015 ◽  
Vol 41 (3) ◽  
pp. 116-120 ◽  
Author(s):  
Paweł Winiarski ◽  
Adam Kłossowicz ◽  
Jacek Wróblewski ◽  
Andrzej Dziedzic ◽  
Wojciech Stęplewski
Keyword(s):  
Thin Film ◽  
Electrical Properties ◽  
Low Temperature ◽  
Wide Temperature Range ◽  
Linear Temperature Dependence ◽  
Content Type ◽  
Temperature Range ◽  
Wide Range ◽  
Thin Film Resistors ◽  
Thermal Shocks

Purpose – The purpose of this paper is to characterize electrical properties of nickel-phosphorus (Ni-P) thin-film resistors made on FR-4 laminate in a wide range of temperature (from −180 to 20°C). Design/methodology/approach – The study was performed using resistors made of Ni-P foil with two different thicknesses (0.1 or 0.05 μm) and sheet resistances (100 or 250 Ω/sq), respectively. The resistance rectangular resistors had length and width from the range between 0.59 and 5.91 mm. The resistance versus temperature characteristics and their distribution as well as resistors ' durability to low-temperature thermal shocks were investigated. Findings – The results showed almost linear temperature dependence of resistance with a negative temperature coefficient of resistance of about −95 ppm/°C for 250 Ω/sq layer and −55 ppm/°C for 100 Ω/sq layer. A very small dimensional effect was observed for sheet resistance as well as for R(T) characteristic. Thin-film resistors are also characterized by very high durability to low-temperature thermal shocks. Originality/value – The results presented in this paper can be very useful for low-temperature applications of thin-film resistors made on printed circuit boards. They suggest possibility of wide applications of these components in a wide temperature range.

scholarly journals Effect of MMT Clay Content on Thermal Behaviour of MDPE/MMT Nanocomposite

2010 ◽  
Vol 19 (5) ◽  
pp. 096369351001900
Author(s):  
J. Sargolzaei ◽  
M. Tavakol ◽  
Akbarabady
Keyword(s):  
Ammonium Salt ◽  
Room Temperature ◽  
Clay Content ◽  
Decomposition Temperature ◽  
Temperature Range ◽  
Air Atmosphere ◽  
Uniform Dispersion ◽  
Wide Range ◽  
Mmt Clay ◽  
Alkyl Ammonium

The thermal stability of medium-density polyethylene (MDPE)/Montmorillonite nanocomposite was studied by TGA and DSC methods in a wide range of temperature. The dispersion of the MMT clays on microscopic scales was examined using a Transmission electron microscopy (TEM). The mass loss from thermogravimetric analysis (TGA) was used to study decomposition temperature in a temperature range from room temperature to 800 °C and DSC was used to probe melting and crystallization in a temperature range from room temperature to 300°C. Simultaneous TGA made possible to show that non modified MMT clay and MMT clay modified with alkyl ammonium salt exhibit a significant stabilizing effect on MDPE macromolecules in air atmosphere and DSC shows natural MMT and MMT clay modified with alkyl ammonium salt exhibit a significant change in melting, crystallization, enthalpy and crystalline content of samples. TEM image shows uniform dispersion and intercalation of MMT clays in nanocomposites.

Coarsening in Critical Dynamics of 2D XY-Model

2015 ◽  
Vol 233-234 ◽  
pp. 8-11 ◽  
Author(s):  
Ivan Popov ◽  
P. Prudnikov
Keyword(s):  
Critical Behavior ◽  
Wide Temperature Range ◽  
Cluster Size ◽  
Xy Model ◽  
Critical Dynamics ◽  
Slow Dynamics ◽  
Temperature Range ◽  
The Past ◽  
Wide Range ◽  
Non Equilibrium

In the past few years, systems with slow dynamics have attracted considerable interest. Coarsening effects are exhibited in a wide range of systems. Non-equilibrium critical behavior of 2D XY-model demonstrates slow dynamics in a wide temperature range. The coarsening in pure and diluted 2D XY-model are investigated for various defects concentration. The period of logarithmic grows of cluster size was found.

Investigation of the tribological performance of reciprocating seals in a wide temperature range

2021 ◽  
pp. 135065012110047
Author(s):  
Chao Peng ◽  
Xiaoping Ouyang ◽  
Katharina Schmitz ◽  
Wei Wang ◽  
Shengrong Guo ◽  
...  
Keyword(s):  
Wide Temperature Range ◽  
High Viscosity ◽  
Tribological Performance ◽  
Influence Coefficient ◽  
Analysis Model ◽  
Element Analysis ◽  
Temperature Range ◽  
Sealing Performance ◽  
Wide Range ◽  
Influence Coefficient Method

Reciprocating seals are widely used in general industrial machines and are designed to endure rigorous working conditions. Among the harshest challenges, the wide temperature range they withstand has a significant influence on their sealing performance. However, most studies of reciprocating seals have focused only on their sealing characteristics at normal temperatures. To investigate the impacts of temperature on the seal's tribological performance, this paper examines the VL seal, a kind of combined seals, and discusses its performance in a wide temperature range. Material properties of the VL seal at temperatures from −55 °C to 135 °C are measured based on the seal product. The thermo-viscosity effect and the influence of thermal expansion and contraction are both considered in the reciprocating seal modelling. A coupling method that combines the finite-element analysis model with a mixed-lubrication procedure is implemented. For deformation calculation, a comparison between the influence coefficient method and the semi-infinite space method is conducted, and finds only minuscule disparities for the VL-seal analysis. To avoid the divergent problem due to high viscosity at low temperatures, this paper proposes the successive approaching method. Details of the sealing zone in the outstroke and instroke are systematically discussed in relation to a wide range of temperatures. The corresponding experiments are conducted and compared with the simulation. The results indicate that the temperature has a tremendous influence on the tribological performance. The leakage and the friction at the high temperature are much higher than those at the normal temperature.

scholarly journals Modeling of Inhomogeneous 4H-SiC Schottky and JBS Diodes in a Wide Temperature Range

2016 ◽  
Vol 858 ◽  
pp. 741-744 ◽  
Author(s):  
Besar Asllani ◽  
Maxime Berthou ◽  
Dominique Tournier ◽  
Pierre Brosselard ◽  
Phillippe Godignon
Keyword(s):  
Low Temperature ◽  
Schottky Barrier ◽  
Barrier Height ◽  
Wide Temperature Range ◽  
Reverse Bias ◽  
Schottky Contact ◽  
Bias Current ◽  
Strong Impact ◽  
Temperature Range ◽  
Wide Range

This paper presents a study of the Schottky barrier evolution on SBD and JBS diodes over a wide range of temperatures from 80 to 500 K. We show that inhomogeneities of the Schottky contact have a strong impact on the dependence of barrier characteristics with temperature, especially below 200 K. Analysis of the reverse bias current of such diodes at low temperature show that the barrier height depends on temperature but also on voltage.

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