The Role of Sodium Hydroxide in the System C3A-CaSO4-H2O at 30°C

1986 ◽  
Vol 85 ◽  
Author(s):  
Hanaa Youssef Ghorab ◽  
Safaa Hussein Abou El Fetouh
Keyword(s):  
Solid Solution ◽  
Sodium Hydroxide ◽  
Calcium Hydroxide ◽  
Hydration Product ◽  
Ion Concentration ◽  
Molar Ratio ◽  
Alkaline Solutions ◽  
Hydration Reaction ◽  
X Ray Diffraction

ABSTRACTThe hydration reaction of C3A with gypsum (molar ratio = 1:1.5) has been studied in water and in sodium hydroxide solutions at 30°C. The hydration product were analyzed microscopically and by means of X-ray diffraction. The concentration of sulfate and aluminum in solution was determined spectrophotometrically. In the absence of alkali, the amount of ettringite formed passes through a maximum and is accompanied by almost complete consumption of sulphate ion in solution. Alkali depresses the formation of ettringite and accelerates that of calcium hydroxide. The monosulfate hydrate appears immediately in alkaline solutions and water then reappears after a day as a solid solution with the tetracalcium aluminate hydrate. The formation of the monophase solid solution is accompanied by the consumption of C3A, ettringite, and calcium hydroxide and by an increase in the amount of the dissolved aluminum. The presence of alkali markedly increases the initial sulfate ion concentration from solution.

Formation of Solid Solution and Metallic Nickel Phases During Suspension Plasma Spraying of Co Oxide and Ni Oxide

2021 ◽  
Author(s):  
Vahid Jalilvand ◽  
Ali Dolatabadi ◽  
Christian Moreau ◽  
Saeed Mohammadkhani ◽  
Lionel Roué ◽  
...  
Keyword(s):  
Solid Solution ◽  
Inert Anode ◽  
Metallic Nickel ◽  
Aluminum Production ◽  
X Ray Diffraction ◽  
Oxide Coatings ◽  
Cobalt Nickel ◽  
Sprayed Coatings ◽  
Insight Into

Abstract The focus of this study is the formation of a solid solution and metallic nickel in the cobalt-nickel mixed oxide coatings during suspension plasma spray (SPS) deposition. The (Co,Ni)O solid solution is a potential material for inert anode applications in aluminum production. SPS coatings and in-flight collected particles are studied to gain further insight into the melting and mixing phenomena of the NiO and CoO powders as well as phase formation in the deposited coatings. Moreover, the role of suspension feedstock particle sizes on the microstructure of coatings is discussed. SEM, EDS and X-ray diffraction studies helped better understanding the formation of different crystalline phases within the as-sprayed coatings. It was found that the formation of metallic nickel is possible in the coatings. The results support the importance of substrate temperature on the formation of metallic Ni, so that keeping the substrate at low temperature results in an increase of the Ni content in the coatings. In this study, possible causes for the formation of metallic Ni during spraying are discussed.

Effect of Added-Calcium Thermal Activated Coal Gangue on Cement Hydration

2011 ◽  
Vol 71-78 ◽  
pp. 833-836
Author(s):  
Xu Yan Song ◽  
Jing Yun Han ◽  
Zhi Hai Gao
Keyword(s):  
Water Content ◽  
Hydration Product ◽  
Coal Gangue ◽  
Hydration Reaction ◽  
X Ray Diffraction ◽  
Specific Strength ◽  
Activated Coal ◽  
Pozzolanic Properties ◽  
Activated Coal Gangue ◽  
Xrd Method

Through determining Ca(OH)2 content and chemically combined water content, hydration degree of cement with added-calcium thermal activated coal gangue may be analyzed. Variation of mineral composition during hydration process of system was analyzed by X-ray diffraction(XRD) method. Simultaneously, specific strength index was applied to study pozzolanic effect of activated coal gangue. The results can show high contribution of added-calcium coal gangue calcined at 1050°C for pozzolanic properties and high hydration reaction degree in this kind of activared coal gangue cement system, with fewer Ca(OH)2 content, more chemically combined water content and obviously reduced hydration product Ca(OH)2 at each age.

Experimental Research on High-Strength Super Sulphate Cement Paste Mixed with Superfine Mineral Admixtures

2014 ◽  
Vol 629-630 ◽  
pp. 150-155
Author(s):  
Jun Wang ◽  
Bao Ying Yu ◽  
Long Yang ◽  
Yu Xin Gao ◽  
Jia Yu Xiang
Keyword(s):  
Silica Fume ◽  
High Strength ◽  
Hydration Product ◽  
Mineral Admixtures ◽  
Hydration Reaction ◽  
X Ray Diffraction ◽  
Cement Ratio ◽  
X Ray ◽  
Early Strength ◽  
Scanning Electron

Aimed at the performance affect of high-strength super sulphate cement (SSC) paste mixed with superfine mineral admixtures, influence of microbead and silica fume replacing SSC quantity on high-strength SSC paste compression strength were studied under water-cement ratio 0.18; Hydration product morphology and phase were further compared by scanning electron microscopy and X-ray diffraction analyzer in this paper. Results show that, compared with sample HS-1, 3-day strength of HS-2 and HS-3 were increased by 5% and 10%, 28d strength basically unchanged; Furthermore, early strength of HS-7 sample slightly higher and late strength basically unchanged. SSC by adding 5% microbead and 3% silica fume (HS-11) has compressive strength 50.8MPa at 3 days and 86.1MPa at 28 days is significantly higher than other samples. Early strength of HS-11sample mainly depends on hydration reaction of SSC and particle filling effect of admixtures, later strength is due to accelerating consumption of gypsum and promoting formation of ettringite.

Synthesis of Ti3Si0.4Al0.8C1.8 Solid Solution

2008 ◽  
Vol 368-372 ◽  
pp. 995-997
Author(s):  
Cui Wei Li ◽  
Hong Xiang Zhai ◽  
Yang Zhou ◽  
Shi Bo Li ◽  
Zhi Li Zhang
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Scanning Electron Microscopy ◽  
Single Phase ◽  
Lattice Parameters ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Powder Mixtures ◽  
X Ray ◽  
Scanning Electron

In this study, free Ti/Si/Al/C powder mixtures with molar ratio of 3:0.4:0.8:1.8 were heated in Argon with various schedules, in order to reveal the possibility for the synthesis of Ti3Si0.4Al0.8C1.8 solid solution powder. X-ray diffraction (XRD) was used for the evaluation of phase identities of the powder after different treatments. Scanning electron microscopy (SEM) was used to observe the morphology of the Ti3Si0.4Al0.8C1.8 solid solution. XRD results showed that predominantly single phase samples of Ti3Si0.4Al0.8C1.8 was prepared after heating at 1400oC for 5 min in Argon and the lattice parameters of Ti3Si0.4Al0.8C1.8 lay between those of Ti3SiC2 and Ti3AlC2.

The Influence of ZnO Components on the Photocatalytic Activity of Fe3O4-CuO-ZnO Nanocomposites

2015 ◽  
Vol 1123 ◽  
pp. 227-232 ◽  
Author(s):  
Iqriah Kalim Susanto ◽  
Ardiansyah Taufik ◽  
Rosari Saleh
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Diffuse Reflectance Spectroscopy ◽  
Uv Light ◽  
Sol Gel ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Uv Visible

Nanocomposite Fe3O4-CuO-ZnO with different molar ratio of Fe3O4:CuO:ZnO were synthesized using sol-gel method and characterized by X-ray diffraction, energy dispersive X-ray spectroscopy, field emission scanning electron microscope, UV-visible diffuse reflectance spectroscopy and vibrating sample magnetometer. The characterization results manifested that the combination of Fe3O4, CuO and ZnO nanoparticles was successful. The photocatalytic activity of nanocomposite with the molar ratio of 1:1:5 was more effective in the degradation of methylene blue under UV light irradiation than pure Fe3O4, CuO, ZnO. The role of photoactive species involved in the photocatalytic reaction was studied and found that holes play the most important role in photodegradation of methylene blue.

The Role of H in Superconducting HxYBa2Cu3O7

1987 ◽  
Vol 99 ◽  
Author(s):  
C. Y. Yang ◽  
S. M. Heald ◽  
J. J. Reilly ◽  
M. Suenaga
Keyword(s):  
Solid Solution ◽  
Atomic Structure ◽  
Solution Phase ◽  
Solid Solution Phase ◽  
Superconducting Transition ◽  
X Ray Diffraction ◽  
X Ray ◽  
X Ray Absorption ◽  
Hydride Phases

ABSTRACTWe have examined the role of H on the superconductivity properties, the atomic structure, and the electronic state in the HxYBa2Cu3O7. The hydrogen solid solution phase (up to ×≃O.2) exhibits a superconducting transition at 94 K, which was usually slightly higher than the starting oxide (YBa2Cu3O7, while the hydride phases (H rich) are not superconducting. Infrared (IR), x-ray diffraction, and x-ray absorption spectroscopy (XAS) measurements indicate that H is located interstitially only near Cu sites.

Study of Geopolymeric Binders of Fly Ash/Metakaolin Mixtures Cured at Room Temperature

2014 ◽  
Vol 600 ◽  
pp. 338-344 ◽  
Author(s):  
Alexandre Silva de Vargas ◽  
Ruby M. de Gutierrez ◽  
João Castro-Gomes
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Room Temperature ◽  
Alkaline Solutions ◽  
X Ray Diffraction ◽  
Precursor Material ◽  
Electron Microscopy Analysis ◽  
Microscopy Analysis

Geopolymerization is a chemical process in which aluminosilicate materials are precursors to obtain binders that have a low environmental impact. Fly ash has been used as a precursor for the development of these binders. However, thermal curing is needed to accelerate the polycondensation of aluminosilicate, which limits the application of this new binder in the construction industry. Thus, the objective of this study was to evaluate the feasibility to obtain such binders with good mechanical properties when cured at room temperature. The precursor material consisted of different mixtures of fly ash and metakaolin that were activated using combined sodium hydroxide and sodium silicate alkaline solutions. The effect on the compressive strength of different proportions of the alkaline solutions was studied. Compressive strengths of about 40 MPa were achieved at 91 days for the samples containing 70% fly ash and 30% metakaolin, activated using an alkaline solution of 50% sodium hydroxide and 50% sodium silicate. X-ray diffraction analysis showed the formation of natrite in geopolymeric samples, as well as the presence of crystalline compounds, such as quartz, mullite and hematite, in fly ash and metakaoline. Scanning electron microscopy analysis showed that in geopolymeric mixtures with higher compressive strength dissolution of fly ash and metakaolin particles occurred almost completely and that aluminosilicate dense gel has been formed extensively.

Role of Chromium in High-Dose, High-Rate, Elevated Temperature Nitrogen Implantation of Austenitic Stainless Steels

1991 ◽  
Vol 235 ◽  
Author(s):  
D. L. Williamson ◽  
I. Ivanov ◽  
R. Wei ◽  
P. J. Wilbur
Keyword(s):  
Solid Solution ◽  
Elevated Temperature ◽  
Stainless Steels ◽  
Depth Profiling ◽  
Austenitic Stainless Steels ◽  
High Dose Rate ◽  
High Rate ◽  
High Dose ◽  
X Ray Diffraction

ABSTRACTIn order to help establish the role of Cr in high-dose, high-dose-rate, elevated temperature N implantation of austenitic (fcc) stainless steels, similar implantations into fee Ni80Fe20 and Ni80Cr20 alloys have been made and characterized by Auger depth profiling and X-ray diffraction. For the Ni-Fe alloy a shallow layer fcc(∼ 0.2 μm) containing an ordered fee γ'-(Ni0.8Fe0.4)4N phase is induced. In contrast, for the Ni-Cr alloy a much thicker N-containing layer (∼ 0.2 μm) is produced consisting primarily of a high-N solid solution fee phase. The fractions of the implanted N retained in Ni-Fe and Ni-Cr were approximately 10 and 100%, respectively. The mechanisms by which Cr is promoting the deep migration and high retention of N in solid solution are proposed.

Role of stress on the phase control and dielectric properties of (1-x) BiFeO3 - xBa0.5Sr0.5TiO3 solid solution thin films

2005 ◽  
Vol 875 ◽  
Author(s):  
Chin Moo Cho ◽  
Hee Bum Hong ◽  
Kug Sun Hong
Keyword(s):  
Thin Films ◽  
Solid Solution ◽  
Dielectric Properties ◽  
Loss Tangent ◽  
Lattice Parameter ◽  
X Ray Diffraction ◽  
Parameter Mismatch ◽  
Si Substrates ◽  
Bst Films

AbstractDielectric properties and structure of (1-x) BiFeO3 (BFO) - x Ba0.5Sr0.5TiO3 (BST) (x = 0 ∼1) solid solution thin films were investigated. All films were prepared at 600 oC on (111) oriented Pt / TiO2 / SiO2 / Si substrates by pulsed laser deposition (PLD) technique. Solid solution could be achieved in all composition ranges, evidenced by X-ray diffraction (XRD) and field emission scanning electric microscope (FE-SEM). The intermediate compositions (0.4 = x = 0.8) exhibited a distinct (111) oriented cubic perovskite structure, while rhombohedra symmetry was found in the x < 0.4 range. Dielectric constant and tunability of the (1-x) BFO – x BST films within this composition region (0.4 = x = 0.8) decreased from 1110 to 920 at 1 MHz, and increased from 28.34 % to 32.42 % at 200 kV/cm, respectively, while loss tangent remains constant. A systematic decrease in lattice parameter with BST addition reduced stress due to reduction of lattice parameter mismatch between film and the substrate. In that range, the improvement of the dielectric properties without a degradation of loss tangent is attributed to the presence of the stress relaxation, which was quantitatively confirmed by a surface profiler based on Stoney's equation.

NMR Structural Characterization of Mg-Containing Nano-Apatite

2014 ◽  
Vol 631 ◽  
pp. 57-60
Author(s):  
Satoshi Hayakawa ◽  
Toshiisa Konishi ◽  
Tomohiko Yoshioka ◽  
Eiji Fujii ◽  
Kouji Kawabata
Keyword(s):  
Calcium Phosphate ◽  
Structural Characterization ◽  
Molar Ratio ◽  
Nanometer Scale ◽  
Potential Candidate ◽  
X Ray Diffraction ◽  
Calcium Phosphate Layer ◽  
Blood Purification Therapy ◽  
Bone Substitute Materials

Nanometer scale Ca-deficient hydroxyapatite (nanoapatite) is a potential candidate as artificial bone substitute materials owing to its similarity to the bone with respect to composition, morphology and osteoclastic degradation or adsorbent materials for blood purification therapy to remove pathogenic substances. The initial biodegradation behaviors, the initial cell-material interaction and the protein adsorption properties of nanoapatite must depend on the microstructure. The purpose of this study is the preparation of nanoapatite particles and their structural characterization by using X-ray diffraction (XRD) and solid-state NMR spectroscopy. The nanoapatite particles were prepared by precipitation processing method, and the effects of magnesium ions on the precipitation of calcium phosphate were examined, because Mg ions are well-known to play a role of inhibition of crystal growth. The addition of Mg ions led to the precipitation of nanometer scale Ca-deficient apatite crystals having 1.33-1.63 of the molar ratio (Mg+Ca)/P. NMR analyses showed that the microstructure of Mg•HAp particles can be explained by a crystalline HAp core covered with a thin amorphous hydrated calcium phosphate layer.

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