Pb-FREE SOLDERS: ESTIMATING OF SOME PHYSICOCHEMICAL AND THERMODYNAMIC PROPERTIES OF TERNARY Cu-Ag-In SYSTEM

2019 ◽  
Vol 26 (10) ◽  
pp. 1950076 ◽  
Author(s):  
SALMA BELMOUJOUD ◽  
RACHIDA M’CHAAR ◽  
ABDELAZIZ SABBAR
Keyword(s):  
Surface Tension ◽  
Cross Sections ◽  
Theoretical Models ◽  
Enthalpy Of Mixing ◽  
Positive Temperature Coefficient ◽  
Ternary Alloys ◽  
Positive Temperature ◽  
Geometric Models ◽  
Different Temperatures ◽  
Increasing Temperature

The surface tension and viscosity in the liquid Cu-Ag-In ternary alloys have been estimated using Muggianu and Toop geometric models and Seetharaman–Sichen equations, respectively along a cross-section of [Formula: see text]/[Formula: see text], 1/1 and 2/1. The surface tension has also been estimated using Butler equation. In addition, the enthalpies of the same ternary alloys have been predicted at different temperatures along five cross-sections [Formula: see text]/[Formula: see text], 1/2, 1/1, 2/1 and 3/1 using Kohler, Toop and Chou models. The geometric models are used in this work in order to verify their effectiveness since they are considered as the most widespread theoretical models used for metallic alloys. The estimated values obtained show that the surface tension decreases with increasing temperature for the all studied models and equations and increase with increasing copper-composition, except for few Cu-compositions where an opposite tendency is observed. It should be noted that the surface tension has a negative and positive temperature coefficient (d[Formula: see text]/d[Formula: see text]. The viscosity decreases with increasing temperature but increases with increasing copper-compositions. The calculated surface tension and enthalpy of mixing of the investigated system are compared with the reachable experimental data and a relatively excellent accord was obtained.

Temperature Dependence of Hole Impact Ionization Coefficient in 4H-SiC Photodiodes

2009 ◽  
Vol 615-617 ◽  
pp. 311-314 ◽  
Author(s):  
W.S. Loh ◽  
J.P.R. David ◽  
B.K. Ng ◽  
Stanislav I. Soloviev ◽  
Peter M. Sandvik ◽  
...  
Keyword(s):  
Phonon Scattering ◽  
Impact Ionization ◽  
Positive Temperature Coefficient ◽  
Positive Temperature ◽  
Different Temperatures ◽  
Ionization Coefficients ◽  
Increasing Temperature ◽  
The Impact ◽  
Good Agreement ◽  
Ionization Rates

Hole initiated multiplication characteristics of 4H-SiC Separate Absorption and Multiplication Avalanche Photodiodes (SAM-APDs) with a n- multiplication layer of 2.7 µm were obtained using 325nm excitation at temperatures ranging from 300 to 450K. The breakdown voltages increased by 200mV/K over the investigated temperature range, which indicates a positive temperature coefficient. Local ionization coefficients, including the extracted temperature dependencies, were derived in the form of the Chynoweth expression and were used to predict the hole multiplication characteristics at different temperatures. Good agreement was obtained between the measured and the modeled multiplication using these ionization coefficients. The impact ionization coefficients decreased with increasing temperature, corresponding to an increase in breakdown voltage. This result agrees well with the multiplication characteristics and can be attributed to phonon scattering enhanced carrier cooling which has suppressed the ionization process at high temperatures. Hence, a much higher electric field is required to achieve the same ionization rates.

Pb-free solders: Predicting of some physicochemical properties of Ag–Cu–Sn material at different temperatures

2016 ◽  
Vol 15 (07) ◽  
pp. 1650062 ◽  
Author(s):  
Rachida M’chaar ◽  
Mouloud El Moudane ◽  
Abdelaziz Sabbar ◽  
Ahmed Ghanimi
Keyword(s):  
Surface Tension ◽  
Physicochemical Properties ◽  
Molar Volume ◽  
The Other ◽  
Ternary Alloys ◽  
Other Hand ◽  
Different Temperatures ◽  
Experimental Values ◽  
Increasing Temperature ◽  
Good Agreement

In this paper, the surface tension, molar volume and density of liquid Ag–Cu–Sn alloys have been calculated using Kohler, Muggianu, Toop, and Hillert models. In addition, the surface tension and viscosity of the Ag–Cu–Sn ternary alloys at different temperatures have been predicted on the basis of Guggenheim and Seetharaman–Sichen equations, respectively. The results show that density and viscosity decrease with increasing tin and increasing temperature for the all studied models. While the surface tension shows a different tendency, especially for the Kohler and Muggianu symmetric models. On the other hand, the molar volume increases with increase of temperature and tin compositions. The calculated values of surface tension and density of Ag–Cu–Sn alloys are compared with the available experimental values and a good agreement was observed.

Experimental Study of Surface Tension Coefficient for Magnetic Fluid

2011 ◽  
Vol 492 ◽  
pp. 277-282
Author(s):  
Qing Lei Wang ◽  
De Cai Li ◽  
Fan Wang
Keyword(s):  
Surface Tension ◽  
Magnetic Fluid ◽  
Liquid Surface ◽  
Surface Tension Coefficient ◽  
Fluid Surface ◽  
Liquid Surface Tension ◽  
Experimental Apparatus ◽  
Different Temperatures ◽  
Increasing Temperature ◽  
The Relationship

The author measured surface tension coefficient for liquid with a new experimental apparatus, measured magnetic fluid surface tension coefficient at different temperatures and with different volume of surfactant. By the analysis of experimental data, we obtained that magnetic fluid surface tension coefficient decreases with the increasing temperature and increases with the addition of surfactant volume and reaches a certain stability value. We also obtained the expression of magnetic fluid surface tension coefficient and the temperature or surfactant. This paper discussed the relationship between the liquid surface tension coefficient and the temperature and surfactant from the view of thermodynamics.

Effect of Pre- and Post-Treatment Temperatures, Age of Deposit, and Repellency on the Toxicity of Kelthane to the Two-spotted Mite, Tetranychus telarius (L.) (Acarina: Tetranychidae)

1964 ◽  
Vol 96 (10) ◽  
pp. 1307-1312 ◽  
Author(s):  
R. W. Fisher ◽  
R. I. C. Hansell
Keyword(s):  
Temperature Coefficient ◽  
Spider Mite ◽  
Positive Temperature Coefficient ◽  
Positive Temperature ◽  
Expected Number ◽  
Significant Difference ◽  
Treated Leaf ◽  
Different Temperatures ◽  
Pre Treatment ◽  
Two Spotted Spider Mite

AbstractKelthane MF showed a positive temperature coefficient of toxicity to the two-spotted spider mite, Tetranychus telarius. An increase of about 1.2% mortality occurred for each degree rise in the range from 50-90°F. Pre-treatment of adult, female mites at three different temperatures for three days caused no significant difference in mortality at 74°F. Acaricidal potency of Kelthane MF on peach leaves declined rapidly both indoors and outdoors for the first two days. Thereafter the potency decreased at about the same rate outside, but much slower in the laboratory. Deposits on peach leaves repelled mites strongly for two days, but weakened rapidly over the next six days. Mites entered treated leaf areas after the acaricidal potency had dropped low, and so a larger than expected number of susceptible mites may have survived.

Influence of sintering process on electrical properties and PTCR effect of laminated Ba1.005(Ti1−xNbx)O3 ceramics fired in a reducing atmosphere

2017 ◽  
Vol 31 (16-19) ◽  
pp. 1744061
Author(s):  
Xuxin Cheng ◽  
Xiaoxia Li ◽  
Xiaoming Chen ◽  
Haining Cui
Keyword(s):  
Electrical Properties ◽  
Room Temperature ◽  
Dopant Concentration ◽  
Positive Temperature Coefficient ◽  
Positive Temperature ◽  
Sintering Process ◽  
Dopant Content ◽  
Reducing Atmosphere ◽  
Ptcr Effect ◽  
Different Temperatures

This study investigates the influence of dopant content and firing conditions on electrical properties and positive temperature coefficient of resistance (PTCR) effect of Ba[Formula: see text](Ti[Formula: see text]Nb[Formula: see text]O3 (BTN) ceramics sintered at different temperatures from 1070[Formula: see text]C to 1220[Formula: see text]C for 2 h in a reducing atmosphere and reoxidized within the temperature range of 600[Formula: see text]–[Formula: see text]750[Formula: see text]C for 0.5[Formula: see text]–[Formula: see text]8 h. The results indicate that the room-temperature (RT) resistance of the laminated BTN specimens initially decreased and then increased as a function of the dopant concentration. Moreover, the resistance jump exhibited a contrasting tendency. Furthermore, the RT resistance of the BTN samples rapidly decreased at first and then gradually decreased with increasing sintering temperature. Meanwhile, the resistance jump of the samples increased first and then decreased. In addition, the influence of reoxidation times on the PTCR characteristics of ceramics was investigated.

A scanning electron microscope study of defects in PTC materials

1988 ◽  
Vol 46 ◽  
pp. 942-943
Author(s):  
James W. Smith
Keyword(s):  
Positive Temperature Coefficient ◽  
Inrush Current ◽  
Positive Temperature ◽  
Scanning Electron Microscope Study ◽  
Limited Temperature ◽  
Limited Temperature Range ◽  
Ideal Tool ◽  
Increasing Temperature ◽  
Solid Form ◽  
Voltage Breakdown

BaTiO3 and its solid solutions with PbTiO3 and SrTiO3 are normally insulators but, when doped with small amounts of trivalent ions, they become semiconducting. Materials in this family also possess a positive temperature coefficient of resistance (an increase in resistance with increasing temperature) over a limited temperature range and are often referred to as PTCs. The temperature where the PTC region begins is determined by the Ba/Pb/Sr ratio.The materials are generally prepared by solid state reaction of a mixture of oxides and carbonates which is subsequently sintered into a solid form. The electrical properties of such a body, in particular properties such as inrush current capability and voltage breakdown, are critically affected by microdefects in the materials which often originate during processing. The SEM is an ideal tool for studying such defects since they generally manifest themselves as localized variations in resistance.

scholarly journals Beating Thermal Deterioration of Magnetization with Mn4C and Exchange Bias in Mn–C Nanoparticles

Nanomaterials ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 1056 ◽  
Author(s):  
Ping-Zhan Si ◽  
Xin-You Wang ◽  
Hong-Liang Ge ◽  
Hui-Dong Qian ◽  
Jihoon Park ◽  
...  
Keyword(s):  
Temperature Coefficient ◽  
Exchange Bias ◽  
Arc Discharge ◽  
Magnetic Ordering ◽  
Positive Temperature Coefficient ◽  
Positive Temperature ◽  
Thermal Deterioration ◽  
Increasing Temperature ◽  
P Type ◽  
Discharge Method

The magnetization of most materials decreases with increasing temperature due to thermal deterioration of magnetic ordering. Here, we show that Mn4C phase can compensate the magnetization loss due to thermal agitation. The Mn–C nanoparticles containing ferrimagnetic Mn4C and other Mn–C/Mn-O phases were prepared by using the traditional arc-discharge method. A positive temperature coefficient of magnetization (~0.0026 Am2 kg−1 K−1) and an exchange bias up to 0.05 T were observed in the samples. We ascribe the exchange bias to the co-existence of ferrimagnetic Mn4C/Mn3O4 and antiferromagnetic α-Mn(C)/MnO phases. The positive temperature coefficient of magnetization of the samples was ascribed to the presence of Mn4C phase, which is considered as a Néel’s P-type ferrimagnet.

scholarly journals Temperature dependences of surface tension, density and viscosity study of Sn-Ag-Cu with Bi additions using theoretical models

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Rachida M’chaar ◽  
Abdelaziz Sabbar ◽  
Mouloud El Moudane
Keyword(s):  
Surface Tension ◽  
Molar Volume ◽  
Liquidus Line ◽  
Theoretical Models ◽  
Quaternary Alloys ◽  
Temperature Range ◽  
Temperature Dependences ◽  
Calculation Results ◽  
Viscosity Study ◽  
Increasing Temperature

Abstract In this work, the kohler, Muggianu,Toop and Hillert geometric models were used to calculate the surface tension, molar volume and density of the liquid Sn-Ag-Cu-Bi quaternary alloys along three selected sections xSn:xAg:xCu = 1:1:1, 1:1:2 and 1:2:1 in the temperature range of 923 K–1423 K. The choice of this temperature range was made on the basis of the calculation results of the liquidus line of the alloys belonging to the three sections. The same properties have been estimated for five selected Sn2.7Ag0.86Cu3.86Bi, Sn3.13Ag0.48Cu4.02Bi, Sn2.95Ag0.53Cu6.81Bi, Sn2.68Ag1.01Cu6.62Bi and Sn3.24Ag0.75Cu1.76Bi quaternary alloys between 623 K and 1123 K for comparison with the available experimental data. Moreover, the surface tension and density of these five alloys have also been calculated on the basis of Guggenheim and theoretical equation, respectively. In addition, the Seetharaman-sichen and Kaptay equations were extended to estimate the viscosity of SAC + Bi alloys. We also discussed the influence of Bismuth addition in liquid Sn-Ag-Cu-Bi. Estimated values show that Bi increases molar volume and density but decreases the surface tension and viscosity. On the other hand, the surface tensions diminish with the temperature for the all studied models, with the exception of some concentration of Bismuth; an inverse tendency is observed (dσ/dT) > 0. While, the density diminishes with increasing temperature for all alloys (dσ/dT) < 0. These models have been shown to be a great alternative for calculating the thermo-physical properties of quaternary systems.

The Temperature Dependent Breakdown Voltage For 4H- and 6H-SiC Diodes

2000 ◽  
Vol 622 ◽  
Author(s):  
Y. S. Lee ◽  
M. K. Han ◽  
Y. I. Choi
Keyword(s):  
High Temperature ◽  
Temperature Coefficient ◽  
Breakdown Voltage ◽  
Impact Ionization ◽  
Positive Temperature Coefficient ◽  
Positive Temperature ◽  
Ionization Coefficient ◽  
Temperature Dependent ◽  
Increasing Temperature ◽  
Temperature Applications

ABSTRACTThe breakdown voltages of 6H- and 4H-SiC rectifiers as function of temperature were modeled analytically in both non-reachthrough diode and reachthrough diode. The breakdown voltage was derived by the ionization integral employing accurate hole impact ionization coefficient. The breakdown voltage of SiC rectifiers was increased with increasing temperature and the positive temperature coefficient of breakdown voltage indicates that SiC rectifiers are suitable for high temperature applications. The breakdown voltages of both 6H- and 4H-SiC diodes were increased by M(T)-1/4 in NRDs and M(T)-1/8 in RDs.

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