Journal: Journal of Thermal Analysis and Calorimetry

Abbreviation

J Therm Anal Calorim

Publisher

Springer

Journal Volumes

ISSN

1388-6150
1588-2926

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Publications 1 - 6 of 6
  • Fast differential scanning calorimetry to mimic additive manufacturing processing: specific heat capacity analysis of aluminium alloys
    Item type: Journal Article
    Quick, Cameron R.; Dumitraschkewitz, Phillip; Schawe, Jürgen E.K.; et al. (2023)
    Journal of Thermal Analysis and Calorimetry
    Eutectic AlSi12, commonly used in casting and in additive manufacturing, is investigated with Fast Differential Scanning Calorimetry to determine the impact of different cooling rates from the liquid state upon the apparent specific heat capacity on subsequent heating. A heat flow correction strategy is developed and refined for the reliable and precise measurement of sample heat flow using chip sensors and assessed by the evaluation of results on pure (99.999%) aluminium. That strategy is then applied to the study of the AlSi12 eutectic alloy, and rate-dependent perturbations in the measured apparent specific heat capacity are discussed in terms of Si supersaturation and precipitation. Several cooling rates were implemented from - 100 to - 30,000 K s(-1), and subsequent heating ranged from + 1000 to + 30,000 K s(-1). After rapid cooling, a drop in AlSi12 apparent specific heat capacity is found on heating above similar to 400 degrees C; even at rates of + 10,000 K s(-1), a result which has high relevance in metal additive manufacturing where similarly fast temperature cycles are involved. The Literature data, temperature modulated DSC and CALPHAD simulations on the heat capacity of AlSi12 are used to provide comparative context to the results from Fast Differential Scanning Calorimetry.
  • Performance of composites with metakaolin-blended cements
    Item type: Journal Article
    Krajči, Ľudovít; Mojumdar, Subhash C.; Janotka, Ivan; et al. (2015)
    Journal of Thermal Analysis and Calorimetry
  • Influence of measuring conditions on the quantification of spectroscopic signals in TA-FTIR-MS systems
    Item type: Journal Article
    Eigenmann, F.; Maciejewski, Marek; Baiker, Alfons (2006)
    Journal of Thermal Analysis and Calorimetry
  • Influence of superabsorbent polymers on hydration of cement pastes with low water-to-binder ratio
    Item type: Journal Article
    Justs, Janis; Wyrzykowski, Mateusz; Winnefeld, Frank; et al. (2014)
    Journal of Thermal Analysis and Calorimetry
    Internal curing with superabsorbent polymers (SAP) is a method for promoting hydration of cement and limiting self-desiccation, shrinkage and cracking in high-performance, and ultra high-performance concrete with low water-to-binder ratio. SAP are introduced in the dry state during mixing and form water-filled inclusions by absorbing pore solution. The absorbed solution is later released to the cement paste during hydration of the cement. In this paper, cement pastes with low water-to-binder ratios incorporating superplasticizer and different dosages of SAP and corresponding additional water were prepared. Reference cement pastes without SAP but with the same amount of water and superplasticizer were also mixed. Isothermal calorimetry was used to measure hydration heat flow. Water entrainment by means of SAP increased the degree of hydration at later hydration times in a manner similar to increasing the water-to-binder ratio. Addition of SAP also delayed the main calorimetric hydration peak compared to the reference pastes, however, in a less prominent manner than the increase in water-to-cement ratio.
  • A simple method for determining the total amount of physically and chemically bound water of different cements
    Item type: Journal Article
    Lura, Pietro; Winnefeld, Frank; Fang, Xing (2017)
    Journal of Thermal Analysis and Calorimetry
    For Portland cements, Powers’ model provides a simple method for calculating the total amount of water bound by cement hydration (both physically and chemically bound). On the other hand, no such simple model is available for other types of cements that are of increasing interest, such as calcium aluminate cements and calcium sulfoaluminate cements. The main uncertainty for these types of cement regards the amount of physically bound water in the hydrates, while the amount of chemically bound water can be calculated, e.g., by thermodynamic modeling. In this paper, a simple approach for estimating the total amount of bound water of different cements is presented. This novel approach consists in measuring the rate of heat liberation of cement pastes made with the same cement, starting at low water-to-cement ratio (w/c) and increasing it steadily. As the cumulative heat of hydration reaches a plateau for a given w/c and does not increase for further increases in the water amount, this w/c is interpreted as total water demand of the cement. The method is tested with a Portland cement, showing that it is in broad agreement with Powers’ model. First results for calcium aluminate cement and calcium sulfoaluminate cement are presented, from which estimations of the amount of physically and chemically bound water are obtained.
  • About thermostability of biocompatible Ti–Zr–Ag–Pd–Sn amorphous alloys
    Item type: Journal Article
    Nicoara, Mircea; Buzdugan, Dragos; Locovei, Cosmin; et al. (2018)
    Journal of Thermal Analysis and Calorimetry
Publications 1 - 6 of 6