Synthesis and characterization of NaAlSi2O6 jadeite doped with different metallic oxides under high pressure and high temperature

2019 ◽  
Vol 33 (34) ◽  
pp. 1950427
Author(s):  
Liang Zhao ◽  
Hongan Ma ◽  
Chao Fang ◽  
Luyao Ding ◽  
Baomin Liu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
High Pressure ◽  
High Temperature ◽  
Raw Materials ◽  
Experimental Studies ◽  
Molar Ratio ◽  
Molecular Vibration ◽  
Fine Grained ◽  
Composition Formula ◽  
Geological Conditions

According to the mineral composition [Formula: see text] of jadeite, [Formula: see text] and [Formula: see text] with a molar ratio of 1:1 were selected as raw materials. One sample was undoped, and five samples were mixed with 0.4 wt.% [Formula: see text], MnO, CoO, [Formula: see text] and [Formula: see text], respectively. The experimental studies were executed under the synthetic condition of 5 GPa pressure and [Formula: see text] temperature using China-type large volume cubic high-pressure apparatus (CHPA) (SPD-6X1200). After the experiment, compositions of the synthetic jadeites were characterized by X-ray diffraction, microstructures characterized by field emission scanning electron microscopy (FESEM) and the high-resolution transmission electron microscopy (HRTEM), molecular vibration types investigated by Raman spectra. The color-causing ion of the synthetic jadeites was investigated by UV–Vis Spectra. The results show that the synthetic jadeites have excellent crystallinity and fine-grained texture and similar structural behavior with natural jadeite. UV–Vis Spectra indicated that different colors of samples have different ion absorption peaks, thus showing different colors. This experiment explored the geological conditions of synthetic jadeite by means of high pressure and high temperature (HPHT) to give a favorable experimental basis for synthetic jadeite and analyze the coloration mechanism of jadeite by way of ion-doping.

Changes in the defect structure of diamond due to high temperature+ high pressure treatment

1975 ◽  
Vol 344 (1636) ◽  
pp. 111-130 ◽  
Keyword(s):  
Electron Microscopy ◽  
High Pressure ◽  
High Temperature ◽  
Optical Absorption ◽  
Defect Structure ◽  
Pressure Treatment ◽  
High Pressure Treatment ◽  
X Ray ◽  
High Temperature High Pressure ◽  
Absorption Measurements

Type la and type IIa diamonds have been heated to temperatures in the range 2000-2300 °C under a pressure of about 4.8 GPa. The changes in the defect structure of these diamonds as a result of the heat treatm ent have been examined by optical absorption measurements, integrated X-ray spike measurements and by electron microscopy. Type la diamonds changed colour from colourless to yellow after being heated for 1 min in the temperature range 2250-2300 °C and it has been shown that the yellowing was due to scattering. The scattering centres responsible were elliptically shaped cracks in the cube planes with their longest dimension in a <110> direction

Investigation on Properties of Magnesia Grinding Wheels Used in Silicon Wafer Grinding

2014 ◽  
Vol 1017 ◽  
pp. 273-278
Author(s):  
Bing Jun Hao ◽  
Zhi Gang Dong ◽  
Shang Gao ◽  
Ren Ke Kang ◽  
Dong Ming Guo
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Integrated Assessment ◽  
Experimental Studies ◽  
Molar Ratio ◽  
Rockwell Hardness ◽  
Grinding Wheels ◽  
Curing Conditions ◽  
Molar Ratios ◽  
Scanning Electron

This paper presents the results of an experimental investigation on molar ratios of MgO/ MgCl2 affecting the hardness of magnesia grinding wheels, which is one of the most important properties. Magnesite grinding blocks of different ratios of MgO/MgCl2 were prepared. The surface Rockwell hardness of which was tested under the same curing conditions. By an integrated assessment of the experimental studies of hardness and component, it is recognized that the molar ratios of MgO/MgCl2 can significantly affect the properties of magnesia grinding wheels. With the increase of MgO/MgCl2 molar ratio, hardness of the specimens increases. Scanning electron microscopy (SEM) studies on grinding blocks of different ratios indicated that micro needle shaped crystal structure of phase 5 are mainly responsible for hardness development. Finally the optimal recipe was selected in consideration of the characteristics of the silicon mechanical chemical grinding (MCG), which was verified to be effective by the following grinding experiment.

Synthesis and characterization of NaAlSi2O6 jadeite under high pressure and high temperature

2014 ◽  
Vol 28 (22) ◽  
pp. 1450175 ◽  
Author(s):  
Fang Biao Wang ◽  
Yong Li ◽  
Ning Chen ◽  
Xiao Peng Jia ◽  
Hong An Ma
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Raw Materials ◽  
Deep Understanding ◽  
Experimental Results ◽  
Synthesis And Characterization ◽  
New Approach ◽  
The Earth ◽  
Amorphous Glass

With Al 2( SiO 3)3 and Na 2 SiO 3 ⋅ 9 H 2 O as raw materials, the NaAlSi 2 O 6 jadeite was synthesized in the temperature range of 1000–1600°C under 5.0 GPa conditions. Amorphous glass materials are entirely converted to crystalline NaAlSi 2 O 6 jadeite at 5.0 GPa and 1450°C. All the experimental results reveal that the properties of synthetic NaAlSi 2 O 6 resemble the natural jadeite very much. The research indicates that we provide a new approach to synthesize NaAlSi 2 O 6 and offer an essential guideline for jewelry, which will be helpful for deep understanding on the origin of natural jadeite and the metamorphism of magma within the Earth.

scholarly journals RhSn3 and the Modifications of RhSn4 – Structure and 119Sn Mössbauer spectroscopic characterization

2019 ◽  
Vol 74 (2) ◽  
pp. 203-209
Author(s):  
Thomas Fickenscher ◽  
Stefan Lösel ◽  
Harald Hillebrecht ◽  
Jutta Kösters ◽  
Theresa Block ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Spectroscopic Characterization ◽  
Molar Ratio ◽  
Final Annealing ◽  
X Ray ◽  
High Temperature Modification ◽  
Density Treatment ◽  
Tin Coordination

AbstractSingle crystals of the high-temperature modification of RhSn4 were obtained from a tin flux (1:20 molar ratio; final annealing at 920 K; dissolution of the tin matrix in 2N HCl). The structure was refined from single-crystal X-ray diffractometer data: I41/acd, a=629.73(5), c=2288.36(18) pm, wR2=0.0382, 447 F2 values and 14 variables. β-RhSn4 is isotypic with β-IrSn4. The rhodium atoms have slightly distorted square-antiprismatic tin coordination with Rh–Sn distances of 4×273.4 and 4×274.1 pm. The RhSn8 units are condensed via common edges to layers that are staggered with respect to each other and stacked in ABCD sequence. A 119Sn Mössbauer spectroscopic characterization of ß-RhSn4 and the stannides RhSn3 and α-RhSn4 shows the typical isomer shifts for transition metal stannides. Only for α-RhSn4 the three crystallographically independent tin sites could be resolved, a consequence of the different s-electron density. Treatment of α-RhSn4 under high-pressure (up to 10 GPa)/high-temperature (up to T=1370 K) conditions leads to decomposition into Rh1.5Sn, RhSn2 and β-Sn.

scholarly journals The Influence of Incinerated Sewage Sludge as an Aggregate on the Selected Properties of Cement Mortars

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5846
Author(s):  
Teresa Rucińska ◽  
Anna Głowacka ◽  
Robert Sidełko
Keyword(s):  
Sewage Sludge ◽  
Building Materials ◽  
Raw Materials ◽  
Experimental Studies ◽  
Municipal Sewage ◽  
Municipal Sewage Sludge ◽  
Natural Sand ◽  
Fine Grained ◽  
Cement Mortars ◽  
Natural Aggregates

In line with the trend of using waste raw materials in the technology of building materials, experimental studies of cement mortars containing various amounts of fine-grained waste aggregate were carried out. The waste aggregate was based on an incinerated municipal sewage sludge which was mechanically crushed to an appropriate grading. Chemical and physical properties of the waste aggregate are presented. Mortars with varying amounts of waste aggregate as a replacement for natural sand were prepared. Study determines compressive strength and flexural strength up to 56 days. Properties such as capillary action, air content and thermal conductivity were determined. The results of the tests has shown that the incinerated waste sludge can be used as a partial or total replacement for natural aggregate. In mortars with waste aggregate, a favorable relation between flexural and compressive strengths was observed, which translates into increased strength of the interfacial transition zone. A significant increase in water absorption was observed for mortars containing high amounts of waste aggregate, which is directly related to its porous structure. Conducted studied prove that the aggregate obtained from incineration of the municipal sewage sludge can a feasible alternative for natural aggregates in production of masonry and rendering mortars for construction purposes.

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