Structural Characterization and Thermal Decomposition of Lime Binders Allow Accurate Radiocarbon Age Determinations of Aerial Lime Plaster

Radiocarbon ◽  
2020 ◽  
Vol 62 (3) ◽  
pp. 633-655 ◽  
Author(s):  
Michael B Toffolo ◽  
Lior Regev ◽  
Eugenia Mintz ◽  
Ifat Kaplan-Ashiri ◽  
Francesco Berna ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Isotopic Signature ◽  
Secondary Phases ◽  
X Ray Diffraction ◽  
Lime Mortar ◽  
X Ray ◽  
Radiocarbon Age ◽  
Carbon Recovery ◽  
Lime Plaster ◽  
Thin Section Petrography

ABSTRACTRadiocarbon (14C) dating of anthropogenic carbonates (CaCO3) such as ash, lime plaster and lime mortar, has proven a difficult task due to the occurrence of a number of contaminants embedded within the CaCO3 pyrogenic binder. These include 14C-free geologic components and/or secondary phases bearing an unknown amount of 14C, and thus the alteration of the original pyrogenic isotopic signature of the material results in major age offsets when carbon recovery is performed through acid hydrolysis. Here we present a characterization/quantification approach to anthropogenic carbonates that includes Fourier transform infrared spectroscopy (FTIR), X-ray diffraction, thin section petrography, thermogravimetric analysis and scanning electron microscopy coupled with high-resolution cathodoluminescence, with which we identified the pyrogenic CaCO3 fraction in an aerial lime plaster and two hydraulic mortars. The preserved pyrogenic component was then isolated by density separation and its purity checked again using FTIR. Carbon was recovered through thermal decomposition in vacuum. The resulting 14C age matches the expected age of the lime plaster, whereas hydraulic mortars are slightly offset due to the carbonation of calcium hydroxide lumps. This approach highlights the importance of a dedicated characterization strategy prior to dating and may be applied to aerial lime plasters to obtain accurate ages.

TEM and X-Ray Examinations of Intermetallic Phases and Carbides Precipitation in an Fe-Ni Superalloy during Prolonged Ageing

2013 ◽  
Vol 212 ◽  
pp. 15-20
Author(s):  
Kazimierz J. Ducki ◽  
Jacek Mendala ◽  
Lilianna Wojtynek
Keyword(s):  
Heat Treatment ◽  
Solution Heat Treatment ◽  
Intermetallic Phase ◽  
Intermetallic Phases ◽  
Precipitation Process ◽  
Secondary Phases ◽  
X Ray Diffraction ◽  
Solid Samples ◽  
Structural Investigations ◽  
X Ray

The influence of prolonged ageing on the precipitation process of the secondary phases in an Fe-Ni superalloy of A-286 type has been studied. The samples were subjected to a solution heat treatment at 980°C for 2 h and water quenched, and then aged at temperatures of 715, 750 and 780°C at holding times from 0.5 to 500 h. Structural investigations were conducted using TEM and X-ray diffraction methods. The X-ray phase analyses performed on the isolates were obtained by anodic dissolution of the solid samples. After solution heat treatment the alloy has the structure of twinned austenite with a small amount of undissolved precipitates, such as carbide TiC, carbonitride TiC0.3N0.7, nitride TiN0.3, carbosulfide Ti4C2S2, Laves phase Ni2Si, and boride MoB. The application of ageing causes precipitation processes of γ-Ni3(Al,Ti), G (Ni16Ti6Si7), η (Ni3Ti), β (NiTi) and σ (Cr0.46Mo0.40Si0.14) intermetallic phases, as well as the carbide M23C6. It was found that the main phase precipitating during alloy ageing was the γ intermetallic phase.

scholarly journals A Facile Method to Construct MXene/CuO Nanocomposite with Enhanced Catalytic Activity of CuO on Thermal Decomposition of Ammonium Perchlorate

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2457 ◽  
Author(s):  
Haifeng Zhao ◽  
Jing Lv ◽  
Junshan Sang ◽  
Li Zhu ◽  
Peng Zheng ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Catalytic Activity ◽  
Ammonium Perchlorate ◽  
Photoelectron Spectra ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Improved Performance ◽  
Calcination Method

In this work, a mixing-calcination method was developed to facilely construct MXene/CuO nanocomposite. CuO and MXene were first dispersed in ethanol with sufficient mixing. After solvent evaporation, the dried mixture was calcinated under argon to produce a MXene/CuO nanocomposite. As characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), and X-ray photoelectron spectra (XPS), CuO nanoparticles (60–100 nm) were uniformly distributed on the surface and edge of MXene nanosheets. Furthermore, as evaluated by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA), the high-temperature decomposition (HTD) temperature decrease of ammonium perchlorate (AP) upon addition of 1 wt% CuO (hybridized with 1 wt% MXene) was comparable with that of 2 wt% CuO alone, suggesting an enhanced catalytic activity of CuO on thermal decomposition of AP upon hybridization with MXene nanosheets. This strategy could be further applied to construct other MXene/transition metal oxide (MXene/TMO) composites with improved performance for various applications.

scholarly journals Znx-1CuxMn2O4 Spinels; Synthesis, Structural Characterization and Electrical Evaluation

2019 ◽  
Vol 54 (1) ◽  
Author(s):  
Francisco Méndez-Martínez ◽  
Federico González ◽  
Enrique Lima ◽  
Pedro Bosch ◽  
Heriberto Pfeiffer
Keyword(s):  
Impedance Spectroscopy ◽  
Structural Characterization ◽  
Morphological Changes ◽  
Secondary Phases ◽  
Varistor Ceramic ◽  
X Ray Diffraction ◽  
X Ray ◽  
Copper Addition ◽  
Partial Inverse ◽  
Scanning Electron

This work presents the structural characterization and electrical evaluation of Znx-1CuxMn2O4 spinels, which are materials presented as secondary phases into the varistor ceramic systems. Samples were analyzed by X-ray diffraction, solid-state nuclear magnetic resonance, infrared spectroscopy, scanning electron microscopy and impedance spectroscopy. Although, the addition of copper to the ZnMn2O4 spinel did not produce morphological changes, the structure and electrical behaviors changed considerably. Structurally, copper addition induced the formation of partial inverse spinels, and its addition increases significantly the electrical conductivity. Therefore, the formation of Znx-1CuxMn2O4 spinels, as secondary phases into the varistor materials, may compromise significantly the varistor efficiency.   Ceramic, Impedance Spectroscopy, spinel, Varistor, XRD.

Accelerated Thermal Decomposition of Graphene Oxide Films in Air via in Situ X-ray Diffraction Analysis

2016 ◽  
Vol 120 (27) ◽  
pp. 14984-14990 ◽  
Author(s):  
Qin Pan ◽  
Ching-Chang Chung ◽  
Nanfei He ◽  
Jacob L. Jones ◽  
Wei Gao
Keyword(s):  
Thermal Decomposition ◽  
Graphene Oxide ◽  
Diffraction Analysis ◽  
Oxide Films ◽  
X Ray Diffraction ◽  
X Ray

scholarly journals Effect of Small Additions of Cr, Ti, and Mn on the Microstructure and Hardness of Al–Si–Fe–X Alloys

Metals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 136 ◽  
Author(s):  
Víctor Aranda ◽  
Ignacio Figueroa ◽  
Gonzalo González ◽  
J. García-Hinojosa ◽  
Gabriel Lara-Rodríguez
Keyword(s):  
Vickers Microhardness ◽  
Melting Furnace ◽  
Alloy System ◽  
Secondary Phases ◽  
X Ray Diffraction ◽  
Microstructural Refinement ◽  
X Ray ◽  
Arc Melting ◽  
Elemental Chemical Analysis ◽  
Mn Additions

The Al–Si–Fe system has drawn the attention of the scientific community due to its capacity to replace parts in several manufacturing industries, as this alloy system is very sensitive to small additions of transition metals. Therefore, the aim of this work is to study the effect of Cr, Ti, and Mn additions in the Al–20Si–5Fe (wt. %) alloy and to study the modification of the iron intermetallic and the microstructural refinement through the formation of secondary phases. Al–20Si–5Fe–X (X = Cr, Mn and Ti at 1.0, 3.0, and 5.0 wt. %) alloy ingots were prepared by arc melting furnace. The elemental chemical analysis was performed by X-ray fluorescence spectrometry (XRF). The microstructure of all samples was investigated by scanning electron microscopy and X-ray diffraction. Finally, microhardness was measured in order correlate the hardness with the formation of the different compounds. The highest hardness was found for the alloy with the 5 wt. % Cr. The addition of Ti and Mn raised the hardness by ~35 HVN (Vickers microhardness) when compared to that of AlSiFe master alloy. Important changes were also observed in the microstructure. Depending on the Cr, Ti, and Mn additions, the resulting microstructure was dendritic (CrFe), acicular (Ti5Si3), and “bone like” (Mn0.2Fe0.8), respectively.

scholarly journals Thermal Decomposition Study on Li2O2 for Li2NiO2 Synthesis as a Sacrificing Positive Additive of Lithium-Ion Batteries

Molecules ◽  
2019 ◽  
Vol 24 (24) ◽  
pp. 4624 ◽  
Author(s):  
Jaekwang Kim ◽  
Hyunchul Kang ◽  
Keebum Hwang ◽  
Songhun Yoon
Keyword(s):  
Thermal Decomposition ◽  
Lithium Ion ◽  
X Ray Diffraction ◽  
Irreversible Capacity ◽  
Powder Preparation ◽  
X Ray ◽  
Preparation Conditions ◽  
Lithium Peroxide ◽  
Lithium Nickel Oxide ◽  
Decomposition Experiments

Herein, thermal decomposition experiments of lithium peroxide (Li2O2) were performed to prepare a precursor (Li2O) for sacrificing cathode material, Li2NiO2. The Li2O2 was prepared by a hydrometallurgical reaction between LiOH·H2O and H2O2. The overall reaction during annealing was found to involve the following three steps: (1) dehydration of LiOH·H2O, (2) decomposition of Li2O2, and (3) pyrolysis of the remaining anhydrous LiOH. This stepwise reaction was elucidated by thermal gravimetric and quantitative X-ray diffraction analyses. Furthermore, over-lithiated lithium nickel oxide (Li2NiO2) using our lithium precursor was synthesized, which exhibited a larger yield of 90.9% and higher irreversible capacity of 261 to 265 mAh g−1 than the sample prepared by commercially purchased Li2O (45.6% and 177 to 185 mAh g−1, respectively) due to optimal powder preparation conditions.

Thermal Decomposition Kinetics of Ammonium Aluminum Carbonate Hydroxide

2008 ◽  
Vol 368-372 ◽  
pp. 1577-1579
Author(s):  
Hai Jun Zhang ◽  
En Xia Xiu ◽  
Xiu Juan Wang ◽  
Quan Li Jia ◽  
Hong Wei Sun ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thermal Decomposition ◽  
Preexponential Factor ◽  
Decomposition Kinetics ◽  
Algebraic Expression ◽  
X Ray Diffraction ◽  
X Ray ◽  
Carbonate Hydroxide ◽  
Kinetics Of ◽  
Scanning Electron

The thermal decomposition of ammonium aluminum carbonate hydroxide was studied under non-isothermal conditions in air. The decomposition kinetics were evaluated from data of TG-DTA by means of the Kissinger equation and the Coats-Redfern equation. The values of the activation energy E, the preexponential factor A and the algebraic expression of integral G(α) functions of the thermal decomposition were calculated. The ammonium aluminum carbonate hydroxide (AACH) was characterized by X-ray diffraction, differential thermal analysis and thermogravimetric and field emission scanning electron microscopy.

In Situ Diffraction Studies: Thermal Decomposition of a Natural Plumbojarosite and the Development of Rietveld-Based Data Analysis Techniques

2010 ◽  
Vol 651 ◽  
pp. 37-64 ◽  
Author(s):  
Ian C. Madsen ◽  
Ian E. Grey ◽  
Stuart J. Mills
Keyword(s):  
Thermal Decomposition ◽  
Amorphous Material ◽  
Data Sets ◽  
X Ray Diffraction ◽  
Data Set ◽  
X Ray ◽  
Analysis Techniques ◽  
Path Lengths ◽  
Instrument Configuration

A study of the thermal decomposition sequence of a sample of natural arsenian plumbojarosite has been undertaken using in situ X-ray diffraction. The sample was heated to 900°C using an Anton-Paar heating stage fitted to an INEL CPS120 diffractometer. The data were analysed using a whole-pattern, Rietveld based approach for the extraction of quantitative phase abundances. The instrument configuration used required the development and application of algorithms to correct for aberrations in the (i) peak intensities due to differing path lengths of incident and diffracted beams in the sample and (ii) peak positions due to sample displacement. Details of the structural models used were refined at selected steps in the pattern and then fixed for subsequent analysis. The data sequence consists of some 110 individual data sets which were analysed sequentially with the output of each run forming the input for analysis of the next data set. The results of the analysis show a complex breakdown and recrystallisation sequence including the formation of a major amount of amorphous material after initial breakdown of the plumbojarosite.

Research on the Thermal Decomposition Process of K-Feldspar-CaSO4-CaO System

2013 ◽  
Vol 734-737 ◽  
pp. 916-920 ◽  
Author(s):  
Jing Xia Chao ◽  
Ju Pei Xia ◽  
Chao Qin Yang ◽  
Zhao Shu Zhang ◽  
Xue Jiao Ren
Keyword(s):  
Thermal Decomposition ◽  
Calcium Sulfate ◽  
Xrd Analysis ◽  
Operating Conditions ◽  
Decomposition Process ◽  
Complex Reaction ◽  
X Ray Diffraction ◽  
Thermal Decomposition Process ◽  
X Ray

The thermal decomposition process of K-feldspar-CaSO4-CaO system was studied by X-ray diffraction (XRD) analysis of the product which calcined at 1473K. The results show that KAlSi3O8 firstly is decomposed into KAlSi2O6 and released the SiO2, then has a complex reaction between KAlSi2O6 and CaO, which generated intermediates-K2SiO3 under the operating conditions. K2SiO3 is unstable and reacted with calcium sulfate to generate K2SO4. When the CaO amount is insufficient, the main products are KAlSi2O6 and 2CaOAl2O3SiO2, the potassium existed as K2S2O8; when n (CaO) / n (KAS6) 12:1, the products will further transfer into CaOSiO2 and 2CaO SiO2 and the potassium existed as K2SO4.

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