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Various carbon dust particles

Studies on thermal behaviour

Journal of Thermal Analysis and Calorimetry
Authors:
Sonja Eichholz
,
Martin Lerch
,
Michael Heck
, and
Dirk Walter

primary particles are clearly visible. At 300 °C, the number of primary particles is decreased due to agglomeration. At 600 °C, nearly no primary particles exist any more. Here, aggregates are formed as a result of a sintering process

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, respectively ( Table 2 ). The production of vessels using lime technology The consolidation of the ceramic body by sintering of the clay usually occurs in firing above 900–1,000 °C [ 28 , 29 ]. In this process, the

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Abstract  

Thermoanalytical methods are used for investigation of outgassing and sintering of hardmetals. Shrinkage (DILA), mass loss (TG), gas evolution (EGA - mass spectrometry) and thermal effects (DSC) allow to describe sintering processes. The results may be applied for a better understanding of technological procedures, e.g. for improvements of temperature-time-atmosphere cycles in the production scale.

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Abstract  

A Maraging M300 steel was produced by ball milling of elemental powders and Spark Plasma Sintering (SPS) consolidation at two different temperatures (950 and 1050 °C). Two types of nanostructured steels have been obtained. Thermal behaviors of these steels were investigated by means of Differential Scanning Calorimetry (DSC) and Dilatometry. Data provided by the two different techniques were seen to be in good agreement. A difference between the behaviors of the steel sintered at 950 °C and that sintered at 1050 °C was observed, due to the material sintered at lower temperature being more reactive to the intermetallics precipitation and austenite reversion on heating. On cooling, it shows a single martensite start temperature (Ms), whereas the steel sintered at 1050 °C shows a double peak for Ms.

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support resulted in the loss of support, and the Ni phase is prone to sintering under higher temperature [ 23 ]. Table 2 The nickel dispersion of catalysts calcined under different temperatures

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Abstract  

Pressureless sintering of CaCO3 was carried out, with Li2CO3 (from 0.5 to 8 wt%) as an additive, under different pressures of CO2. Densification occurs between 600 and 700°C. Sintering above the eutectic temperature (T>662°C) leads to the decomposition of calcium carbonate and the materials become expanded. At 620° under 1 kPa of CO2, a relative density of 96% is reached. Li2CO3 enhances the densification process and grain growth of calcium carbonate. CO2 pressure slows down densification and grain growth kinetics. These results are explained by the influence of carbonate and calcium ion vacancies on the sintering mechanisms.

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500 nm. There is no sign of sintering at this temperature. Fig. 7 Scanning electron microscopy images of ZnCr2O4 powder obtained by ZnCrPVA precursor calcination at a 500 °C and b 1,000 °C

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artificial aggregates available, lightweight aggregates including expandable shale and slate, foamed slag, sintered fly ash aggregate, artificial cinders, and lightweight expanded clay aggregate (LECA) are the most frequently used. Significant recent and

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The processes taking place during outgassing and sintering of different hard metals are investigated by Simultaneous Thermal Analysis (Thermogravimetry and Differential Thermoanalysis) coupled with Mass Spectrometry. In this paper an overview on the application of these methods is given. The progress of gas reactions, their kinetics and the reaction products themselves are characterized more in detail. Main products of the outgassing during the sintering of hard metals are hydrocarbons, carbon monoxide, carbon dioxide and partly nitrogen. The outgassing during the sintering of conventional WC-Co hard metal is finished at relatively low temperatures (approximately 800‡C). The outgassing during the sintering of cermets and of hard metals containing mixed carbides takes place up to higher temperatures (partly up to the formation of the liquid phase). Critical temperature ranges of technological processes may be determinated.

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Abstract  

The authors report on a non-isothermal kinetic investigation (at constant heating rate) of the sintering of manganese and nickel-zinc ferrite powders prepared by coprecipitation. The kinetic results point to the thermal compaction of the powders, which occurs mainly in the intermediate stage of sintering. A comparative study was performed in order to determine the influence of the sample characteristics (such as chemical nature, density and shape) and the heating rate on the kinetics and mechanism of the compaction.

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