scholarly journals Joining Alumina and Sapphire by Growing Aluminium Borate Whiskers In-Situ, and the Whiskers’ Orientation Relationship with the Sapphire Substrate

Materials ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 175 ◽  
Author(s):  
Chun Li ◽  
Xiaoqing Si ◽  
Shuang Wu ◽  
Junlei Qi ◽  
Yongxian Huang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Orientation Relationship ◽  
Sapphire Substrate ◽  
Great Influence ◽  
The Other ◽  
Aluminium Borate ◽  
Random Growth ◽  
The Relationship ◽  
Scanning Electron

Bonding between polycrystal alumina and sapphire with (0001), (10 1 ¯ 0), (11 2 ¯ 0), (1 1 ¯ 02) orientations is successfully achieved by growing aluminium borate whiskers in the joint. The morphology of the whiskers in the joint is characterised by (Scanning Electron Microscopy) SEM. The relationship between the growing direction of the aluminium borate whiskers and the orientation of the sapphire substrate is investigated. The effect of the growing direction of the aluminium borate whiskers on the mechanical properties of the joint is discussed. The results show that the whiskers on the sapphire with (10 1 ¯ 0) orientation grow perpendicular to the surface of the substrate while the whiskers show a random growth on the other substrates. It is found that there is an orientation relationship between the whiskers (220) and sapphire (10 1 ¯ 0) and the morphology of the whiskers has great influence on the mechanical properties of the joint. The joint between polycrystal alumina and sapphire with (10 1 ¯ 0) orientation exhibits the highest strength, which reaches 26 MPa.

scholarly journals Gamma Ray-Induced Polymerization and Cross-Linking for Optimization of PPy/PVP Hydrogel as Biomaterial

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 111 ◽  
Author(s):  
Jin-Oh Jeong ◽  
Jong-Seok Park ◽  
Young-Ah Kim ◽  
Su-Jin Yang ◽  
Sung-In Jeong ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cell Viability ◽  
Gamma Rays ◽  
Biomedical Applications ◽  
Gamma Ray ◽  
The Other ◽  
Cross Linking ◽  
Gamma Ray Irradiation ◽  
Good Cell ◽  
Scanning Electron

Conducting polymer (CP)-based hydrogels exhibit the behaviors of bending or contraction/relaxation due to electrical stimulation. They are similar in some ways to biological organs and have advantages regarding manipulation and miniaturization. Thus, these hydrogels have attracted considerable interest for biomedical applications. In this study, we prepared PPy/PVP hydrogel with different concentrations and content through polymerization and cross-linking induced by gamma-ray irradiation at 25 kGy to optimize the mechanical properties of the resulting PPy/PVP hydrogel. Optimization of the PPy/PVP hydrogel was confirmed by characterization using scanning electron microscopy, gel fraction, swelling ratio, and Fourier transform infrared spectroscopy. In addition, we assessed live-cell viability using live/dead assay and CCK-8 assay, and found good cell viability regardless of the concentration and content of Py/pTS. The conductivity of PPy/PVP hydrogel was at least 13 mS/cm. The mechanical properties of PPy/PVP hydrogel are important factors in their application for biomaterials. It was found that 0.15PPy/PVP20 (51.96 ± 6.12 kPa) exhibited better compressive strength than the other samples for use in CP-based hydrogels. Therefore, it was concluded that gamma rays can be used to optimize PPy/PVP hydrogel and that biomedical applications of CP-based hydrogels will be possible.

Surface Morphology and Shape Analysis of Nonlinear Optical Crystal DAST

2011 ◽  
Vol 197-198 ◽  
pp. 306-309
Author(s):  
Fei You ◽  
Bing Teng ◽  
Lin Hua Xia ◽  
Hui Xu ◽  
De Gao Zhong ◽  
...  
Keyword(s):  
Surface Morphology ◽  
Shape Analysis ◽  
Great Influence ◽  
Nucleation Mechanism ◽  
Two Dimensional ◽  
Crystal Shape ◽  
Nonlinear Optical Crystal ◽  
Optical Crystal ◽  
The Relationship ◽  
Scanning Electron

DAST (4-N, N-dimethylamino-4′-N′-methyl stilbazolium tosylate) crystal has been grown by slope nucleation method (SNM) at different cooling rates (0.5°С/d and 0.1°С/d). The morphology of crystal growing surfaces was observed by scanning electron microscope (SEM) and microscope. Different growth striations were found on the growth surfaces. The arrangements of crystal ions and cooling rate have a great influence on the crystal shape. The relationship between the DAST crystal molecular structure and the crystal shape was systematically studied by analyzing the growing surface morphology. Two-dimensional nucleation mechanism was found on growing faces with increasing supersaturation.

Influence of NaCl on Mechanical Properties and Microstructure of Cement Stone

2013 ◽  
Vol 700 ◽  
pp. 136-139
Author(s):  
Xin Tang ◽  
Jin Huang
Keyword(s):  
Mechanical Properties ◽  
Sodium Chloride ◽  
Crystalline Phase ◽  
The Other ◽  
Cement Stone ◽  
X Ray Diffraction ◽  
X Ray ◽  
Main Crystalline Phase ◽  
Gel Phase ◽  
Scanning Electron

The mechanical properties and microstructure of cement stone containing different sodium chloride (NaCl) have been investigated. Uni-axial compression experiments were used to study mechanical properties. The main crystalline phase composition of cement specimens was determined by means of X-ray diffraction (XRD). Surface morphology of cement stone was observed by using scanning electron microscopy (SEM). The obtained results showed that compared with the other samples, the sample incorporated 14% sodium chloride was quite different, whose compressive strength was higher and microstructure was denser. The sodium chloride crystalline phase and the hydration (C-S-H) gel phase co-existed.

Design of Novel Treated Silica Xerogels: Synthesis, Property and Reinforcement in Silicone Elastomers

1998 ◽  
Vol 520 ◽  
Author(s):  
Q. Deng ◽  
G. T. Bums ◽  
J. R. Hahn ◽  
C. C. Reese ◽  
J. D. Preston ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Surface Area ◽  
Silica Xerogels ◽  
Silicone Elastomers ◽  
Surface Areas ◽  
Reinforcing Fillers ◽  
Controlled Porosity ◽  
The Relationship ◽  
Filler Structure

ABSTRACTTreated silica xerogels with controlled porosity and surface area were prepared by the in-situ treatment of hydrogels with hexamethyldisiloxane in the presence of isopropyl alcohol. The resulting hydrogels were hydrophobic and readily transferred to organic solvents allowing their isolation. The surface area and porosity of the xerogel were controlled by varying the pH, time and temperature used to aggregate the hydrogel prior to treatment. The treated xerogels were evaluated as reinforcing fillers in silicone rubber formulations. When the bases were crosslinked with peroxides, silicone elastomers with acceptable mechanical properties were obtained. The relationship between the surface area, porosity and the type and degree of surface treatment of the xerogel, and its reinforcing ability was studied. In general, the mechanical properties of the elastomer increased as the filler structure increased; however, xerogels with higher surface areas were more difficult to incorporate and gave higher plasticity bases.

Preparation and Properties of PVC-Silica Composites using Different Catalysts Via Sol-Gel Process

1999 ◽  
Vol 576 ◽  
Author(s):  
Khan M. Asif ◽  
M.I. Sarwar ◽  
Z. Ahmad
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Sol Gel ◽  
Silica Network ◽  
Transparent Films ◽  
Sol Gel Process ◽  
Gel Technique ◽  
In Situ Generation ◽  
Scanning Electron

Novel micro-composites from Polyvinyl chloride (PVC) and silica were prepared using sol-gel technique. Different catalysts were used for the in-situ generation of silica network from tetraethylorthosilicate (TEOS) in the PVC matrix. Thin transparent films containing various proportions of silica in PVC were cast by the solvent elution technique. Mechanical properties of these films were studied. The results showed an increase in the value of Young's modulus and strain at rupture by the addition of small amount of silica in PVC. However, the stress at yields point and stress at rupture decreased with the addition of silica contents. Scanning electron microscopy (SEM-EDAX) studies were also performed on these samples.

In Situ Composites: Effect of Intermolecular Hydrogen Bonds on Polyamide 66/TLCP Blends

2007 ◽  
Vol 546-549 ◽  
pp. 1515-1520
Author(s):  
Zhuo Zhang ◽  
Hong Jun Guo ◽  
Wei He ◽  
Wen Xion Zhang
Keyword(s):  
Mechanical Properties ◽  
Fourier Transform ◽  
Electron Microscope ◽  
Liquid Crystalline ◽  
Polyamide 66 ◽  
Intermolecular Hydrogen Bonds ◽  
In Situ Composites ◽  
Infra Red ◽  
Scanning Electron

The thermotropic liquid crystalline copolyamide (TLCPa) was synthesized and the in situ composites for TLCPa/Polyamides 66 (PA66) were prepared by melting extrusion. As revealed by differential scanning calorimeter (DSC), depression of the melting point and the crystallinity of PA66 indicated that the miscibility was enhanced via intermolecular H-bonds. Characteristic absorption shifts of C=O groups of TLCPa/PA66 in Fourier transform infra-red spectra (FTIR) confirmed the existence of H-bonds. Scanning electron microscope (SEM) observation showed that the shape of TLCPa phase change in matrix with increasing TLCPa content. Mechanical properties of blends were significantly improved by good interface adhesion and TLCPa fibrils generation.

scholarly journals Polymerization characteristics of colored compomers cured with different LED units

2019 ◽  
Vol 17 (1) ◽  
pp. 228080001982780 ◽  
Author(s):  
Meltem Bakkal ◽  
Berza Yılmaz ◽  
Ali Durmus ◽  
Zehra Durmus ◽  
Serife Ozalp
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Dental Restoration ◽  
The Other ◽  
Microstructural Properties ◽  
Complex Interactions ◽  
Light Curing ◽  
Degree Of Curing ◽  
Light Absorbance ◽  
Scanning Electron

Aim: Incomplete polymerization of a resin material used for dental restoration affects the properties of the restoration. We evaluated the structural and mechanical properties of three different colored compomers cured with three different LED units to observe the characteristic changes occurring in different matches. Methods: Polytetrafluoroethylene molds (5 mm in diameter and 2 mm in thickness) were used to prepare disk-shaped sample specimens. Nine sample groups (each of five specimens) were prepared, three each of different compomer resin colors (gold, berry, and silver). Samples were cured using three different LED units (Optima, VALO, and Demi Ultra), according to the manufacturers’ instructions. Microstructural properties of samples were characterized by determining the degree of curing using Fourier-transform infrared spectroscopy and by analyzing sample morphology under a scanning electron microscope. The Vickers hardness, compressive strength, and elastic modulus of the samples were measured to investigate their mechanical properties. Results: The degrees of curing decreased in the order of silver > berry > gold for all curing units. Conversely, gold compomers exhibited poorer mechanical values than the berry and silver counterparts. The Optima 10 unit yielded slightly higher degrees of curing than the other devices, followed by Demi Ultra and VALO light-curing units, respectively. Conclusion: The resin color affected the structural and mechanical properties of the compomers, possibly as a result of the complex interactions and relationships between the irradiation light and resin material, such as light absorbance and reflectance; thus, depending on the color as well as the curing protocol.

The Effect of Dispersion Method on the Mechanical Properties of Graphene Reinforced Alumina Composites

2018 ◽  
Vol 281 ◽  
pp. 93-98 ◽  
Author(s):  
Lu Wang ◽  
Jian Qiang Bi ◽  
Wei Li Wang ◽  
Xu Xia Hao ◽  
Xi Cheng Gao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Bending Strength ◽  
Great Influence ◽  
Physical And Mechanical Properties ◽  
Structural Ceramics ◽  
Alumina Matrix ◽  
Dispersion Method ◽  
Mechanical Stirring ◽  
Alumina Composites ◽  
Scanning Electron

Due to the remarkable physical and mechanical properties of graphene, it is considered to be one of the most promising reinforcements for structural ceramics. In this paper, the composite material is compacted by hot pressing and the effects of mechanical stirring and ultrasonic on dispersion of graphene in alumina matrix were investigated, which was believed to have a great influence on the mechanical properties of the hot-pressed composites. It is found that from Scanning electron microscopy (SEM) observation. Compared with ultrasonic, the composite, in which graphene was dispersed by mechanical stirring, showed higher bending strength (555.1MPaVS432.3MPa) and fracture toughness (4.4MPa·m1/2VS 4.1MPa·m1/2). The result is much more promising to be employed in the designing and processing of graphene composites.

Mechanical Properties Of Quasicrystal Dispersed Al-Li-Cu Alloy

1998 ◽  
Vol 553 ◽  
Author(s):  
T. Okada ◽  
T. Nakamura ◽  
K Mitsugi ◽  
K Kozawa ◽  
T Matumura ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloys ◽  
Vickers Hardness ◽  
The Other ◽  
Proof Stress ◽  
Specific Strength ◽  
Cu Alloy ◽  
Ti Alloys ◽  
Maximum Value ◽  
The Relationship

AbstractTo apply the ductile structural materials, the quasicrystal dispersion in aluminum alloys is one of effective methods. We have investigated mechanical properties of quasicrystal dispersed Al- Li-Cu alloy prepared by the twin-type piston anvil apparatus. The slow cooled samples are hard and ductile. The evaluated values of brittleness are from 6.0 to 14 erg for Ef, from 0.52 to 0.73MNm−3/2 for K1c and from 5.5 to 7.7 Nm−1 for Gic for the fastest and slowest cooled samples, respectively. The hardness of the quasicrystal dispersed Al-Li-Cu alloy is higher than that of the other commercial aluminum alloys. Based on the relationship between Vickers hardness and proof stress of aluminum alloys, we estimate the specific strength of Al-Li-Cu quasicrystal alloy. The maximum value is the higher than that of Ti alloys.

The Influence of Spraying Parameters on Stresses and Mechanical Properties of HVOF-Sprayed Co-Cr-W-C Coatings

2014 ◽  
Vol 606 ◽  
pp. 171-174 ◽  
Author(s):  
Jiří Matějíček ◽  
Šárka Houdková ◽  
Olga Bláhová ◽  
Zdenek Pala
Keyword(s):  
Mechanical Properties ◽  
Residual Stresses ◽  
Particle Temperature ◽  
Instrumented Indentation ◽  
Stellite 6 ◽  
Young’S Moduli ◽  
Particle Characteristics ◽  
Spraying Parameters ◽  
The Relationship

Stellite 6 Co-Cr-W-C coatings were sprayed by HVOF while systematically varying the spraying parameters, namely the equivalent ratio and combustion pressure. During spraying, the in-flight particle temperature and velocity were measured. Deposition, thermal and residual stresses were determined by in-situ curvature monitoring of the sprayed samples. Young's moduli and hardness of the coatings were determined by instrumented indentation. The relationship between spraying parameters, in-flight particle characteristics and mechanical properties is discussed.

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