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Journal of Thermal Analysis and Calorimetry
Authors:
Abdelhamid Harabi
,
Djamel Belamri
,
Noureddine Karboua
, and
Fatima-Zohra Mezahi

ways of producing HA, the first one is synthetic method [ 2 – 7 ] and the other one is from natural bone [ 8 – 11 ]. Because of the effectiveness (high) cost of bioceramics production using conventional sintering (CS), due to their higher sintering

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Introduction Sintering of semi-crystalline polymers occurs in those industrial processes, such as rotational molding, where the material is heated in the absence of any external applied pressure [ 1 , 2 ]. Sintering of

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Abstract  

The objective of present research was to sinter nanosized Mn–Zn ferrites (MZF) at low temperature (≤1,000 °C) by avoiding the formation of nonmagnetic phase (hematite). For this purpose, MZF powder was synthesized by sol–gel auto combustion process at 220 °C and further calcined at 450 °C. In calcined powder, single phase (spinel) was confirmed by X-ray diffraction analysis. Pellets were pressed, having 43% of the theoretical density and showing 47 emu gm−1 saturation magnetization (M s). Various combinations of heating rate, dwelling time and gaseous environment were employed to meet optimum sintering conditions at low temperature (≤1,000 °C). It was observed that sintering under air or N2 alone had failed to prevent the formation of nonmagnetic (hematite) phase. However, hematite phase can be suppressed by retaining the green compacts at 1,000 °C for 180 min in air then further kept for 120 min in nitrogen. Under these conditions, spinel phase (comprising of nano crystallites), 90% of theoretical density and 102 emu gm−1 of saturation magnetization has been achieved.

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Introduction As it is known, the densification degree and the microstructure of ceramics influence most of the properties of a sintered material. Thus, in the YBa 2 Cu 3 O 7–x (YBCO or 123) ceramic, the residual porosity and

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Iron ore sintering

Characterization by calorimetry and thermal analysis

Journal of Thermal Analysis and Calorimetry
Authors:
Riham Morcos
and
Alexandra Navrotsky

Abstract  

Differential scanning and high temperature reaction calorimetry have been used to characterize a series of natural iron ore and flux samples commonly used during iron ore sintering. Most iron ore samples were shown to contain measurable quantities of goethite, with a characteristic dehydration peak in DSC and TG between 200 and 400°C. At higher temperatures, all samples decomposed to produce magnetite with an accompanying mass loss in the TG profile due to the evolution of oxygen. High temperature reaction calorimetry has been used to measure the heat of solution of the ore in the melt formed during iron ore sintering. The dehydration and calcination of iron ore and flux samples was also examined using high-temperature reaction calorimetry. The results support the DSC/TG findings.

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glass structure and derive relevant information with respect to the local environment of silicon and aluminium in experimental glasses. The sintering behaviour and properties of the corresponding glass powder compacts have also been targeted in the

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References 1 Palmour , H. Huckabee , M. L. Hare , T. M. 1978 Rate Controlled Sintering, Principles

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Journal of Thermal Analysis and Calorimetry
Authors:
Kaia Tõnsuaadu
,
Kārlis Agris Gross
,
Liene Plūduma
, and
Mihkel Veiderma

properties of apatite. Thermal stability of synthetic hydroxyapatite is of great importance to control sintering or thermal processing conditions for the design and preparation of hydroxyapatite ceramics. Calcination is an important process for

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Introduction Sintering is densification of a powder compact by firing, which is the last step in ceramic production. Sintering parameters may be divided into two major parts such as material variables and process variables [ 1

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Abstract  

Hydroxyapatite powders, which consisted of lath-like single-crystalline particles, were calcined at two different temperatures. Green and calcined powders were used for sintering HAp ceramic samples under uniaxial pressing. Powders and sintered samples were studied using various analytical techniques in order to determine how calcination affects the particle properties and the sintering behavior of HAp powders. It was found that calcination decreases the particles length and changes the particles morphology from lath-like to spherical shape. The relative density increases with increasing calcination temperature and aging time. It was found that long aging time favor the formation of thermally stable HAp particles, whereas a shorter one results in the formation of β-calcium phosphate during thermal treatment. Sintering of compacted powders begins at temperatures greater than 900C, with a trend to increase the onset temperature as the calcination temperature is increased.

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