The significance of the aluminium content of a lizardite at the nanoscale: the role of clinochlore as an aluminium sink

2008 ◽  
Vol 72 (3) ◽  
pp. 817-825 ◽  
Author(s):  
G. Cressey ◽  
B. A. Cressey ◽  
F. J. Wicks
Keyword(s):  
Essential Element ◽  
Nucleation And Growth ◽  
Careful Examination ◽  
Aluminium Content ◽  
X Ray Diffraction ◽  
X Ray ◽  
Al Content ◽  
Transmission Electron ◽  
Coupled Substitution

AbstractLizardite-1T crystals from Gew-graze at the Lizard, Cornwall, of an apparent composition (Mg2.94Fe0.03Al0.03)(Si1.97Al0.03)05(OH)4, have been observed to contain 2–5% of thin interstratifications of clinochlore when investigated by analytical transmission electron microscopy (TEM). The clinochlore is usually only a few unit layers thick but has an extensive lateral dimension parallel to the lizardite layers. Analytical TEM confirms the existence of very low-Al lizardite with a planar structure interstratified with occasional thin units of clinochlore containing substantial Al. Compositionally, such clinochlore (invisible by X-ray diffraction) interstratified throughout the lizardite crystals, could account for most of the Al present. We suggest that an occasional influx of Al causes the nucleation and growth of clinochlore at the expense of lizardite. The possibility of clinochlore contributing to the measured Al content in lizardite samples highlights the need for future investigations of Al-bearing serpentines to include careful examination and interpretation using imaging and analysis by TEM.It has crept into serpentine discussions that lizardite cannot form without the coupled substitution of Al to relieve the misfit between the sheets of octahedra and tetrahedra. The lizardite at Gew-graze is almost Al-free, forms well-crystallized planar crystals and demonstrates that Al is not an essential element for lizardite crystallization.

Detonation Synthesis of Nano-Size Materials

1995 ◽  
Vol 418 ◽  
Author(s):  
J. Forbes ◽  
J. Davis ◽  
C. Wong
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Nucleation And Growth ◽  
Detonation Synthesis ◽  
X Ray Diffraction ◽  
Crystalline Materials ◽  
X Ray ◽  
Transmission Electron ◽  
Nano Size

AbstractThe detonation of explosives typically creates 100's of kbar pressures and 1000's K temperatures. These pressures and temperatures last for only a fraction of a microsecond as the products expand. Nucleation and growth of crystalline materials can occur under these conditions. Recovery of these materials is difficult but can occur in some circumstances. This paper describes the detonation synthesis facility, recovery of nano-size diamond, and plans to synthesize other nano-size materials by modifying the chemical composition of explosive compounds. The characterization of nano-size diamonds by transmission electron microscopy and electron diffraction, X-ray diffraction and Raman spectroscopy will also be reported.

Thermal quenching behavior of Er-doped silicon-rich SiO2 prepared by ion implantation

2004 ◽  
Vol 19 (9) ◽  
pp. 2699-2702 ◽  
Author(s):  
C.S. Zhang ◽  
H.B Xiao ◽  
Y.J. Wang ◽  
Z.J. Chen ◽  
X.L. Cheng ◽  
...  
Keyword(s):  
Silicon Nanocrystals ◽  
Annealing Temperature ◽  
Thermal Quenching ◽  
X Ray Diffraction ◽  
X Ray ◽  
Radiative Processes ◽  
Transmission Electron ◽  
Weak Intensity ◽  
Er Doped

Erbium and silicon were dual implanted into thermally grown SiO2 film on Si (110) substrates, followed by thermal treatment at 700–1200 °C for 30 min. The microstructure was studied by transmission electron microscope and x-ray diffraction. When the implanted films were annealed at T > 900 °C, the silicon nanocrystals (nc-Si) enwrapped by amorphous silicon (a-Si) could be observed. The thermal quenching behavior at λ = 1.535 μm and its relation with the annealling temperature were also investigated. With increasing annealing temperature, the portion of a-Si and the thermal quenching both decreased. Efficient luminescence from Er ions and weak intensity thermal quenching were obtained from the sample annealed at 1100 °C. The role of a-Si in non-radiative processes at T > 100 K is discussed.

Core–shell structures with metallic silver as nucleation agent of low expansion phases in BaO/SrO/ZnO/SiO2 glasses

CrystEngComm ◽  
2019 ◽  
Vol 21 (29) ◽  
pp. 4373-4386 ◽  
Author(s):  
Christian Thieme ◽  
Michael Kracker ◽  
Katrin Thieme ◽  
Christian Patzig ◽  
Thomas Höche ◽  
...  
Keyword(s):  
Scanning Transmission Electron Microscopy ◽  
Nucleating Agent ◽  
Shell Structures ◽  
Metallic Silver ◽  
X Ray Diffraction ◽  
Nucleation Agent ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Transmission

The role of silver as a nucleating agent in BaO/SrO/ZnO/SiO2 glasses is studied with a range of microstructure-characterization techniques, such as scanning transmission electron microscopy, ultraviolet-visible spectroscopy, and X-ray diffraction.

Microstructure and Distribution of Low Content Elements in AlNiCo 9

2017 ◽  
Vol 898 ◽  
pp. 1669-1674 ◽  
Author(s):  
Bin Shao ◽  
Bing Bing Li ◽  
Chun Hong Li ◽  
Yi Long Ma ◽  
Qiang Zheng ◽  
...  
Keyword(s):  
Magnetic Force ◽  
Magnetic Domain ◽  
Magnetic Force Microscope ◽  
X Ray Diffraction ◽  
Rich Phase ◽  
X Ray ◽  
Al Content ◽  
Transmission Electron ◽  
Titanium Sulfide ◽  
High Al Content

The microstructure and the chemistry distribution of AlNiCo 9 samples were characterized by the X-ray diffraction, magnetic force microscope, field emission scanning electron microscopy and transmission electron microscope. An interface of a high Al content was formed near the FeCo-rich phases with a size of about 30 nm. S elements mainly combined with Ti to form titanium sulfide bars with the length between 70-150 μm, while S elements was not confirmed in the nanostructured FeCo-rich phase and AlNi-rich phase. Si and Nb preferably existed in the NiAl-rich phase, and a higher content Nb near the Cu precipitate boundary was observed. Moreover, the magnetic domain structure of AlNiCo 9 was also studied.

Ordering and microwave dielectric properties of Ba(Ni1/3Nb2/3)O3 ceramics

1997 ◽  
Vol 12 (2) ◽  
pp. 518-525 ◽  
Author(s):  
In-Tae Kim ◽  
Yoon-Ho Kim ◽  
Su Jin Chung
Keyword(s):  
Dielectric Properties ◽  
Microwave Dielectric Properties ◽  
Nucleation And Growth ◽  
Annealing Process ◽  
Network Analyzer ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microwave Dielectric ◽  
Transmission Electron ◽  
Rich Liquid

Ordering and microwave dielectric properties of Ba(Ni1/3Nb2/3)O3 have been investigated using x-ray diffraction, transmission electron microscopy, energy-dispersive spectroscopy, and a network analyzer. Samples sintered at 1400 °C for 2 h were disordered and showed the presence of Nb-rich liquid phase at grain boundary junctions. Degree of ordering increased with following annealing at 1300 °C. Growth of the ordered region during the annealing process was discussed in terms of nucleation and growth. A long-range order parameter was calculated using structure factor. Measurements of microwave dielectric properties showed that permittivity and temperature coefficient of resonant frequency decreased with ordering, and quality factor increased with ordering. The correlation between microwave dielectric properties and ordering was discussed in terms of covalency of bonding, inhomogeneous charge distribution, and defects concentration.

Hardness evolution of Al–Cr–N coatings under thermal load

2008 ◽  
Vol 23 (11) ◽  
pp. 2880-2885 ◽  
Author(s):  
Herbert Willmann ◽  
Paul H. Mayrhofer ◽  
Lars Hultman ◽  
Christian Mitterer
Keyword(s):  
Thermal Load ◽  
Structural Changes ◽  
Single Phase ◽  
Volume Fraction ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Al Content ◽  
Annealing Temperatures ◽  
Transmission Electron

Microstructure and hardness evolution of arc-evaporated single-phase cubic Al0.56Cr0.44N and Al0.68Cr0.32N coatings have been investigated after thermal treatment in Ar atmosphere. Based on a combination of differential scanning calorimetry and x-ray diffraction studies, we can conclude that Al0.56Cr0.44N undergoes only small structural changes without any decomposition for annealing temperatures Ta ⩽ 900 °C. Consequently, the hardness decreases only marginally from the as-deposited value of 30.0 ± 1.1 GPa to 29.4 ± 0.9 GPa with Ta increasing to 900 °C, respectively. The film with higher Al content (Al0.68Cr0.32N) exhibits formation of hexagonal (h) AlN at Ta ⩾ 700 °C, which occurs preferably at grain boundaries as identified by analytical transmission electron microscopy. Hence, the hardness increases from the as-deposited value of 30.1 ± 1.3 GPa to 31.6 ± 1.4 GPa with Ta = 725 °C. At higher temperatures, where the size and volume fraction of the h-AlN phase increases, the hardness decreases to 27.5 ± 1.0 GPa with Ta = 900 °C.

scholarly journals Tuning Optical and Granulometric Properties of Gold Nanostructures Synthesized with the Aid of Different Types of Honeys for Microwave-Induced Hyperthermia

Materials ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 898
Author(s):  
Anna Dzimitrowicz ◽  
Piotr Cyganowski ◽  
Piotr Jamroz ◽  
Dorota Jermakowicz-Bartkowiak ◽  
Malgorzata Rzegocka ◽  
...  
Keyword(s):  
X Ray Diffraction ◽  
Hyperthermia Treatment ◽  
X Ray ◽  
Induced Hyperthermia ◽  
Transmission Electron ◽  
Fourier Transformation Infrared Spectroscopy ◽  
Ft Ir ◽  
Honey Solution ◽  
Size Controlled

Size-controlled gold nanoparticles (AuNPs) were synthesised with solutions of three types of Polish honeys (lime, multiflower, honeydew) and used in microwave-induced hyperthermia cancer treatment. Optical and structural properties of nanostructures were optimized in reference to measurements made by using UV/Vis absorption spectrophotometry (UV/Vis), transmission electron microscopy (TEM) supported by energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and attenuated total reflectance Fourier transformation infrared spectroscopy (ATR FT-IR). In addition, concentrations of reducing sugars and polyphenols of honeys applied were determined to reveal the role of these chemical compounds in green synthesis of AuNPs. It was found that the smallest AuNPs (20.6 ± 23.3 nm) were produced using a 20% (w/v) multiflower aqueous honey solution and 25 mg·L−1 of Au(III) ions. These AuNPs were then employed in microwave-induced hyperthermia in a system simulating metastatic tissues. This research illustrated that AuNPs, as produced with the aid of a multiflower honey solution, could be suitably used for microwave-induced heating of cancer. A fluid containing resultant Au nanostructures, as compared to water, revealed facilitated heating and the ability to maintain a temperature of 45 °C required for hyperthermia treatment.

Effects of Thermo-Mechanical Treatment on the Microstructure of AA7085 Aluminum Alloy

2014 ◽  
Vol 794-796 ◽  
pp. 1193-1198 ◽  
Author(s):  
Hong Wei Tong ◽  
Wen Yi Liu ◽  
Guang Jie Huang ◽  
Qing Liu
Keyword(s):  
Electron Microscopy ◽  
Rolled Plate ◽  
X Ray Diffraction ◽  
Warm Deformation ◽  
X Ray ◽  
Free Zone ◽  
Transmission Electron ◽  
Hardness Tests ◽  
Continuous Chain

The microstructure of pre-aged AA7085 rolled plate was studied by means of hardness tests, optical microscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffraction and electrical conductivity tests. The results show that supper refined and homogeneous precipitates were formed during pre-aging, but the hardness of the alloy was still relatively low. There occurred a large number of dislocations when the warm deformation was introduced, and the size of the intragranular precipitates firstly increases and then decreases and then increases with the dislocation density increasing, which was caused by the role of dislocations on inhibiting the formation of GP zone and promoting the nucleation and transformation ofηphase. Meanwhile, the distribution of grain boundary precipitates also changed from continuous chain to coarsening interrupted distribution and the precipitate free zone (PFZ) broadened obviously.

scholarly journals Growth and Characterization of High-Quality GaN Nanowires on PZnO and PGaN by Thermal Evaporation

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
L. Shekari ◽  
H. Abu Hassan ◽  
S. M. Thahab ◽  
Z. Hassan
Keyword(s):  
Gallium Nitride ◽  
Thermal Evaporation ◽  
Lattice Mismatch ◽  
Growth Direction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Gan Nanowires ◽  
Transmission Electron

In the current research, an easy and inexpensive method is used to synthesize highly crystalline gallium nitride (GaN) nanowires (NWs) on two different substrates [i.e., porous zinc oxide (PZnO) and porous gallium nitride (PGaN)] on Si (111) wafer by thermal evaporation without any catalyst. Microstructural studies by scanning electron microscopy and transmission electron microscope measurements reveal the role of the substrates in the nucleation and alignment of the GaN NWs. Further structural and optical characterizations were performed using high-resolution X-ray diffraction, energy-dispersive X-ray spectroscopy, and photoluminescence spectroscopy. Results indicate that the NWs have a single-crystal hexagonal GaN structure and growth direction in the (0001) plane. The quality and density of GaN NWs grown on different substrates are highly dependent on the lattice mismatch between the NWs and their substrates. Results indicate that NWs grown on PGaN have better quality and higher density compared to NWs on PZnO.

scholarly journals Effects of Pr and Yb Dual Doping on the Thermoelectric Properties of CaMnO3

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1807 ◽  
Author(s):  
Cuiqin Li ◽  
Qianlin Chen ◽  
Yunan Yan
Keyword(s):  
Electron Microscopy ◽  
Figure Of Merit ◽  
Low Cost ◽  
X Ray Diffraction ◽  
Thermoelectric Figure ◽  
X Ray ◽  
Transmission Electron ◽  
New Strategy ◽  
Low Toxicity

There has been research on CaMnO3 with natural abundance, low toxicity, and low cost as promising candidates for n-type thermoelectric (TE) materials. In this paper, Ca1−2xPrxYbxMnO3 with different Pr and Yb contents (x = 0, 0.01, 0.02, 0.03, 0.04 and 0.05) were synthesized by means of coprecipitation. With X-ray diffraction (XRD), scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HRTEM), researchers characterized the phase structure and morphology of all the samples. The oxidation states of manganese were determined by X-ray photoemission spectroscopy (XPS). The role of Ca-site dual doping in the TE properties was also investigated. Increasing the Pr and Yb contents leads to decreases in the electrical resistivity and Seebeck coefficient, leading to a power factor of 3.48 × 10−4 W·m−1·K−2 for x = 0.04 at 773 K, which is its maximum. Furthermore, the thermal conductivity (κ) decreases with increasing x, and κ = 1.26 W m−1·K−1 is obtained for x = 0.04 at 973 K. Ca0.92Pr0.04Yb0.04MnO3 exhibit a ZT (thermoelectric figure of merit) value of 0.24 at 973 K, approximately 3 times more than that of the pristine CaMnO3. Thus, the reported method is a new strategy to enhance the TE performance of CaMnO3.

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