THERMAL AND ELECTRICAL PROPERTIES OF ARMCO IRON AT HIGH TEMPERATURES

1960 ◽  
Vol 38 (7) ◽  
pp. 887-907 ◽  
Author(s):  
M. J. Laubitz

Thermal and electrical conductivity, thermoelectric power vs. platinum, and thermal expansion of Armco iron were determined in the temperature range of 0 °C to 1000 °C. All these properties show a discontinuous change at the α–γ transition of iron, and a change in slope at the Curie point. These measurements were carried out as a contribution to a co-operative determination of thermal conductivity of Armco iron at high temperatures.

2012 ◽  
Vol 501 ◽  
pp. 319-323
Author(s):  
Hasan A. Alwi ◽  
Lay S. Ewe ◽  
Zahari Ibrahim ◽  
Noor B. Ibrahim ◽  
Roslan Abd-Shukor

We report the room temperature thermal conductivity κ and thermal diffusivity α of polycrystalline La0.7Ca0.3-xSrxMnO3 for x = 0 to 0.1. The samples were prepared by heating at 1220 and 1320oC. The insulator-metal transition temperature, TIM and thermal diffusivity increased with Sr content. Phonon was the dominant contributor to thermal conductivity and the electronic contribution was less than 1%. Enhancement of electrical conductivity σ and thermal diffusivity for x ≥ 0.08 was observed in both series of samples. The grain size of the samples (28 to 46 µm) does not show any affect on the thermal and electrical properties.


2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Yan Li ◽  
Harshit Porwal ◽  
Zhaohui Huang ◽  
Han Zhang ◽  
Emiliano Bilotti ◽  
...  

Polystyrene- (PS-) graphene nanoplatelets (GNP) (0.1, 1, and 10 wt.%) nanofibers were successfully produced via electrospining of dimethyformamide- (DMF-) stabilized GNP and PS solutions. Morphological analysis of the composite nanofibers confirmed uniform fiber formation and good GNP dispersion/distribution within the PS matrix. The good physical properties of GNP produced by liquid exfoliation were transferred to the PS nanofibers. GNP modified PS nanofibers showed a 6-fold increase in the thermal conductivity and an increase of 7-8 orders of magnitude in electrical conductivity of the nanofibers at 10 wt.% GNP loading.


MRS Advances ◽  
2016 ◽  
Vol 1 (22) ◽  
pp. 1637-1643 ◽  
Author(s):  
Xinyu Wang ◽  
Boyu Peng ◽  
Paddy Chan

ABSTRACTThe thermal and electrical properties of organic semiconductor are playing critical roles in the device applications especially on the devices with large area. Although the effect may be minor in a single device like field effect transistors, the unwanted waste heat would cause much more severe problems in large-scale devices as the power density will go up significantly. The waste heat would lead to performance degradation or even failure of the devices, and thus a more detailed study on the thermal conductivity and carrier mobility of the organic thin film would be beneficial to predict the limits of the device or design a thermally stable device. Here we explore the thermal annealing effect on the thermal and electrical properties of the small molecule organic semiconductor, dinaphtho[2,3-b:2’,3’-f]thieno[3,2-b]thiophene (DNTT). After the post deposition thermal annealing, the grain size of the film increases and in-plane crystallinity improves while cross-plane crystallinity keeps relatively constant. We demonstrated the cross-plane thermal conductivity is independent of the thermal annealing temperature and high annealing temperature will reduce the space-charge-limited current (SCLC) mobility. When the annealing temperature increase from 24 °C to 140 °C, the field effect mobility shows a gradual increase while the threshold voltage shifts from positive to negative. The different dependence of the SCLC mobility and field effect mobility on the annealing temperature suggest the improvement of the film crystallinity after thermal annealing is not the only dominating effect. Our investigation provides the constructive information to tune the thermal and electrical properties of organic semiconductors.


1937 ◽  
Vol 10 (4) ◽  
pp. 798-800
Author(s):  
P. Schidrowitz ◽  
C. A. Redfarn

Abstract In a previous publication (J. Soc. Chem. Ind., 54, 263T–267T (1935); Rubber Chem. and Tech., 8, 613 (1935)) some particulars were given regarding the production and development of a hard spongy material from chlorinated rubber (British Patent No. 424,561). Thermal and Electrical Properties Some preliminary tests on the thermal and electrical properties of the material have now been carried out, and these serve to confirm the view that expanded chlorinated rubber should prove to be a very good insulating material. Thermal Conductivity.—The details given herewith are taken from a report by the Research Association of British Rubber Manufacturers. The thermal conductivity was determined by comparison with cork, a good insulating material of which the thermal properties are fairly well known. The method used consisted in placing slabs of cellular rubber and of cork each between a pair of aluminum plates, and then interposing between the two sets of plates an electric heating plate made of wire enclosed between sheets of mica. The plates, heater, and sheets of expanded chlorinated rubber material and cork were all of the same size, namely, 20.3 by 10.25 cm. The aluminum plates were 0.625 cm. thick.


1947 ◽  
Vol 25a (6) ◽  
pp. 357-374 ◽  
Author(s):  
L. D. Armstrong ◽  
T. M. Dauphinee

An apparatus for measuring the thermal conductivity of metals in the temperature range 0° to 800 °C. is described. The method utilizes unidirectional heat flow in a cylindrical sample in a vacuum. The advantages of the method are outlined and a comprehensive analysis of possible errors in the measurements is included. Measurements on Armco iron indicate that results with an absolute error of less than 2% may be obtained. The results of measurements on a sample of Armco iron gave thermal conductivities of 0.1819 c.g.s units at 0 °C. and 0.0698 c.g.s. units at 800 °C. A change in slope of the thermal conductivity–temperature curve was found at a temperature of approximately 375 °C., and is tentatively attributed to the presence of 0.03% nickel impurity.


2018 ◽  
Vol 913 ◽  
pp. 811-817 ◽  
Author(s):  
Di Wu ◽  
Ji Ai Ning ◽  
De Gang Zhao ◽  
Xue Zhen Wang ◽  
Na Liu

In this study, nanometer WO3 powder was uniformly dispersed into the Cu2SnSe3 powder by ball milling process, and the WO3/Cu2SnSe3 thermoelectric composite was prepared by spark plasma sintering (SPS). The results showed that the nano-WO3 particles were mainly distributed in the grain boundary of Cu2SnSe3 matrix, and the grain growth of Cu2SnSe3 was inhibited. The addition of nano-WO3 could enhance the electrical conductivity of Cu2SnSe3, and while the Seebeck coefficient increased slightly for the 0.4% WO3/Cu2SnSe3 composite. The thermal conductivity was not decreased until the content of WO3 exceeded 1.6%. The highest thermoelectric figure of merit ZT of 0.177 was achieved at 700 K for 0.4% WO3/Cu2SnSe3 composite. The enhancement of ZT value of WO3/Cu2SnSe3 thermoelectric material was mainly attributed to the improvement of the electrical properties.


2016 ◽  
Vol 45 (39) ◽  
pp. 15290-15293
Author(s):  
V. Øygarden ◽  
T. Grande

The effect of Mo-substitution on the crystal structure, thermal expansion and electrical properties is investigated for the LaCoxNiyMozO3 system.


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