scholarly journals Influence of La-impurities and Plasma Treatment on the Structural and Optical Properties of Some Bismuth Calcium Borate Glasses

2021 ◽  
Author(s):  
nasra mohamed ◽  
Hosam M. Gomaa ◽  
H. A. Saudi ◽  
raed M. el shasly ◽  
W. M. El-Meligy ◽  
...  
Keyword(s):  
Optical Absorption ◽  
Plasma Treatment ◽  
Research Work ◽  
Calcium Borate ◽  
Micro Hardness ◽  
Structural And Optical Properties ◽  
Glass Density ◽  
The Matrix ◽  
Fast Cooling ◽  
Xrd Patterns

Abstract This research work aims to the estimation of the effect of the addition of La2O3, by different amounts in wt. %, to the matrix of the bismuth calcium borate glass. The fast cooling procedure was used to prepare the suggested compositions. XRD was used to inspecting the internal structural phases of the prepared samples, where XRD patterns confirmed the amorphous natures of all samples. It was found that the La-additives act to increase the glass density, micro hardness, and optical absorption. While the plasma treatment using N2 acted to reduce both the relative intensity of XRD and the optical absorption.

scholarly journals Microstructures and Mechanical Properties of Nanocrystalline AZ31 Magnesium Alloy Powders with Submicron TiB2 Additions Prepared by Mechanical Milling

Crystals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 550
Author(s):  
Haiping Zhou ◽  
Chengcai Zhang ◽  
Baokun Han ◽  
Jianfeng Qiu ◽  
Shengxue Qin ◽  
...  
Keyword(s):  
Magnesium Alloy ◽  
Mechanical Milling ◽  
Boundary Segregation ◽  
Milling Process ◽  
Az31 Magnesium Alloy ◽  
Micro Hardness ◽  
Submicron Scale ◽  
The Matrix ◽  
Xrd Patterns ◽  
Tib2 Particles

In this work, nanocrystalline AZ31 magnesium alloy powders, reinforced by submicron TiB2 particles, were prepared via mechanical milling. It was found that TiB2 particles stimulated the fracture and welding of AZ31/TiB2 powders, leading to the acceleration of the milling process. Meanwhile, the TiB2 particles were refined to submicron-scale size during the milling process, and their distribution was uniform in the Mg matrix. In addition, the matrix was significantly refined during the milling process, which was also accelerated by the TiB2 particles. The formation of grain boundary segregation layers also led to the weakened TiB2 peaks in the XRD patterns during the mechanical milling. The grain sizes of AZ31–2.5 wt % TiB2, AZ31–5 wt % TiB2 and AZ31–10 wt % TiB2 powders were refined to 53 nm, 37 nm and 23 nm, respectively, after milling for 110 h. Under the combined effect of the nanocrystalline matrix and the well-dispersed submicron TiB2 particles, the AZ31/TiB2 composites exhibited excellent micro-hardness. For the AZ31–10 wt % TiB2 composite, the micro-hardness was enhanced to 153 HV0.5.

scholarly journals Investigation of the microstructure evolution in TP347HFG austenitic steel at 700°C and its characterization method

2021 ◽  
Vol 40 (1) ◽  
pp. 12-22
Author(s):  
Yuetao Zhang ◽  
Tingbi Yuan ◽  
Yawei Shao ◽  
Xiao Wang
Keyword(s):  
Austenitic Steel ◽  
Aging Time ◽  
Microstructure Evolution ◽  
Precipitate Phase ◽  
Dispersion Strengthening ◽  
Micro Hardness ◽  
Dispersed Particles ◽  
Nonlinear Ultrasonic ◽  
The Matrix ◽  
Solution Strengthening

Abstract This article reports the microstructure evolution in TP347HFG austenitic steel during the aging process. The experiments were carried out at 700°C with different aging time from 500 to 3,650 h. The metallographic results show that the coherent twin and incoherent twin are existed in the original TP347HFG grains, while they gradually vanished with the increase of the aging time. After aging for 500 h, a lot of fine, dispersed particles precipitated from the matrix, but they disappeared after aging for 1,500 h. When the aging time extend to 3,650 h, the precipitates appeared apparently coarse in TP347HFG steel, which include the M23C6 and σ phase; besides, the micro-hardness of TP347HFG also changes during the aging, which was closely related to the effect of dispersion strengthening and solution strengthening. The results of the nonlinear ultrasonic measurement reveal that the β′ of TP347HFG steel was also changed with the aging time. It first increased at 0–500 h, then reduced later, and increased finally at 1,500–3,650 h. The variation of β′ in TP347HFG was influenced by a combined effect of the twin microstructure and the precipitate phase, which indicate that the nonlinear ultrasonic technique can be utilized to characterize the microstructure evolution in TP347HFG.

scholarly journals Characterization of Soldering Alloy Type Bi-Ag-Ti and the Study of Ultrasonic Soldering of Silicon and Copper

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 624
Author(s):  
Roman Kolenak ◽  
Igor Kostolny ◽  
Jaromir Drapala ◽  
Paulina Babincova ◽  
Peter Gogola
Keyword(s):  
Eutectic Reaction ◽  
Research Work ◽  
Copper Substrate ◽  
Liquid Bismuth ◽  
Alloy Type ◽  
Average Shear Strength ◽  
Average Shear ◽  
The Matrix ◽  
Solder Microstructure ◽  
Ultrasonic Soldering

The aim of the research work was to characterize the soldering alloy type Bi-Ag-Ti and to study the direct soldering of silicon and copper. Bi11Ag1.5Ti solder has a broad melting interval. Its scope depends mainly on the content of silver and titanium. The solder begins to melt at the temperature of 262.5 ∘C and full melting is completed at 405 ∘C. The solder microstructure consists of a bismuth matrix with local eutectics. The silver crystals and titanium phases as BiTi2 and Bi9Ti8 are segregated in the matrix. The average tensile strength of the solder varies around 42 MPa. The bond with silicon is formed due to interaction of active titanium with the silicon surface at the formation of a reaction layer, composed of a new product, TiSi2. In the boundary of the Cu/solder an interaction between the liquid bismuth solder and the copper substrate occurs, supported by the eutectic reaction. The mutual solubility between the liquid bismuth solder is very limited, on both the Bi and the Cu side. The average shear strength in the case of a combined joint of Si/Cu fabricated with Bi11Ag1.5Ti solder is 43 MPa.

scholarly journals Mechanical properties and microstructural investigation of polypropylene/exfoliated graphite nanoplatelets/ nano-magnesium oxide composites

2018 ◽  
Vol 7 (2) ◽  
pp. 897
Author(s):  
A I. Alateyah ◽  
F H. Latief
Keyword(s):  
Mechanical Properties ◽  
Flexural Modulus ◽  
Exfoliated Graphite ◽  
Graphite Nanoplatelets ◽  
Microstructural Investigation ◽  
The Matrix ◽  
Exfoliated Graphite Nanoplatelets ◽  
Polypropylene Matrix ◽  
Xrd Patterns ◽  
Oxide Composites

Polypropylene/exfoliated graphite nanoplatelets composites reinforced with a low concentration of nano-magnesia have been successfully fabricated, using injection molding machine. The mechanical properties and microstructure of the composites were investigated, in the present study. The XRD patterns of the composites showed the peaks of xGnP and n-MgO, where the intensity of the xGnP peaks became stronger with increasing the concentration of xGnP added into polypropylene matrix. In addition, the SEM micrographs revealed a good dispersion of fillers within the matrix. The results showed that increasing the amount of exfoliated graphite nanoplatelets up to 10 wt. % resulted in increasing the composite flexural strength, flexural modulus, and hardness up to 35% and 91%, 6.7%, respectively, compared to the monolithic polypropylene.  

scholarly journals Functional Application for the Corn Leaf Fibre to Make Reinforced Polymer Composites Sheet

2021 ◽  
Author(s):  
Ramratan Guru ◽  
Anupam Kumar ◽  
Rohit Kumar
Keyword(s):  
Volume Fraction ◽  
Agricultural Waste ◽  
Matrix Material ◽  
Research Work ◽  
Weight Fraction ◽  
Natural Fibre ◽  
Raw Material ◽  
Corn Husk ◽  
The Matrix ◽  
Composite Product

This research work has mainly utilized agricultural waste material to make a good-quality composite sheet product of the profitable, pollution free, economical better for farmer and industries. In this study, from corn leaf fibre to reinforced epoxy composite product has been utilized with minimum 35 to maximum range 55% but according to earlier studies, pulp composite material was used in minimum 10 to maximum 27%. Natural fibre-based composites are under intensive study due to their light weight, eco-friendly nature and unique properties. Due to the continuous supply, easy of handling, safety and biodegradability, natural fibre is considered as better alternative in replacing many structural and non-structural components. Corn leaf fibre pulp can be new source of raw material to the industries and can be potential replacement for the expensive and non-renewable synthetic fibre. Corn leaf fibre as the filler material and epoxy as the matrix material were used by changing reinforcement weight fraction. Composites were prepared using hand lay-up techniques by maintaining constant fibre and matrix volume fraction. The sample of the composites thus fabricated was subjected to tensile, impact test for finding the effect of corn husk in different concentrations.

MOORA-Driven Decision Making to Select the Optimal Specimen of Organic CMCs

2021 ◽  
pp. 48-73
Author(s):  
Rajesh P. V.
Keyword(s):  
Bone Fractures ◽  
Research Work ◽  
Ceramic Matrix Composites ◽  
Matrix Composites ◽  
Powder Metallurgy Technique ◽  
Micro Hardness ◽  
Optimization Of Process Parameters ◽  
Materials Used ◽  
Conch Shell ◽  
Significant Health

Bone grafting or bone implant is a typical procedure in surgery in which a missing or broken bone is replaced in order to treat bone fractures that pose a significant health risk to the patients. Several research works have been carried out in the past few years regarding various composite materials used in bone implants, their fabrication methods, and evaluation of their physical, mechanical, chemical, and thermal properties. The use of ceramic powders and ceramic-based composites in biomedical applications are steadily increasing over years mainly due to their advantages like high compressive strength, excellent hardness, etc. In this research work, organic ceramic matrix composites with varying proportions of conch shell and sea sponge are fabricated using powder metallurgy technique and their physicomechanical properties such as density, porosity, water absorption, and micro-hardness are evaluated. Finally, optimization of process parameters is done using multi-objective optimization based on ratio analysis (MOORA) to select the best possible specimen of CMCs.

scholarly journals Structural and optical properties of AgCl-sensitized TiO2 (TiO2 @AgCl) prepared by a reflux technique under alkaline condition

Cerâmica ◽  
2018 ◽  
Vol 64 (370) ◽  
pp. 190-196 ◽  
Author(s):  
V. A. Mu’izayanti ◽  
H. Sutrisno
Keyword(s):  
Visible Light ◽  
Surface Area ◽  
Alkaline Condition ◽  
Visible Light Region ◽  
X Ray Diffraction ◽  
Structural And Optical Properties ◽  
Light Region ◽  
Vis Spectroscopy ◽  
Xrd Patterns ◽  
Tio2 Rutile

Abstract The AgCl-sensitized TiO2 (TiO2@AgCl) has been prepared from the precursor of TiO2-rutile type which on its surface adsorb chloride anion (Cl-) and various amounts of silver using AgNO3 as starting material: AgNO3/(AgNO3+TiO2) mass ratio of 0.00, 1.14, 3.25, 6.38 and 10.32%. Reflux under alkaline condition was the employed technique. All samples were characterized by X-ray diffraction (XRD) and diffuse reflectance UV-vis spectroscopy. The sample without the addition of AgNO3 was analyzed by scanning electron microscope and surface area analyzer. The morphology of the sample showed a distribution of microspheres of approximately 0.5 to 1.0 µm and the specific surface area was 68 m2/g. XRD patterns indicated that the sample without the addition of AgNO3 contained two types of TiO2: rutile (major) and anatase (minor), whereas the samples with the addition of AgNO3 consisted of one phase of AgCl and two types of TiO2: rutile and anatase. The bandgaps of the samples were in the range of 2.97 to 3.24 eV, which were very close to the bandgap of intrinsic TiO2 powder. The presence of 0.8, 2.6 and 4.4 wt% of AgCl in each sample resulted in an additional bandgap in visible light region of 1.90, 1.94 and 2.26 eV, respectively, whereas the presence of 9.4 wt% of AgCl in the sample resulted in two bandgaps in visible light region of 1.98 and 1.88 eV.

Innovative Composites with Carbon Nanofillers for Self-Sensing Structural RC Beams

2018 ◽  
Vol 19 ◽  
pp. 12-22 ◽  
Author(s):  
A. D'Alessandro ◽  
A. Meoni ◽  
F. Ubertini
Keyword(s):  
Research Work ◽  
Construction Materials ◽  
Reinforced Concrete Beam ◽  
The Self ◽  
Electrical Performance ◽  
Structural Safety ◽  
Cement Pastes ◽  
The Matrix ◽  
Behavior Modifications ◽  
Carbon Nanofillers

The progress of nanotechnology resulted in the development of new instruments in the civil engineering and its applications. In particular, the use of carbon nanofillers into the matrix of construction materials can provide enhanced properties to the material in both of mechanical and electrical performance. In constructions, concrete is among the most used material. Due to the peculiarities of its components and its structure, it is suitable to modifications, at the nanometer level too. Moreover, to guarantee structural safety it is desirable to achieve a diffuse monitoring of structures in order to identify incipient situations of damages and possible risk for people. The ideal solution would be to realize structures able to identify easily and quickly their behavior modifications. This paper presents a research work about the characterization of the self-sensing abilities of novel cementitious composites with conductive carbon nanoinclusions and their application into a structural reinforced concrete beam. The self-sensing evidence is achieved through the correlation between the variation of strains and the variation of electrical resistance or resistivity. Nanomodified cement pastes with different carbon nanofillers has been tested. The experimental campaign shows the potentialities of this new types of sensors made of nanomodified concrete for diffuse Structural Health Monitoring.

The Influence of RuO2 Addition on the Thermoelectric Properties of BiSbTe Alloys

2012 ◽  
Vol 512-515 ◽  
pp. 1651-1654 ◽  
Author(s):  
Yu Kun Xiao ◽  
Zhi Xiang Li ◽  
Jun Jiang ◽  
Sheng Hui Yang ◽  
Ting Zhang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermoelectric Properties ◽  
Lattice Thermal Conductivity ◽  
Combined Process ◽  
Plasma Sintering ◽  
The Matrix ◽  
Spark Plasma ◽  
Xrd Patterns ◽  
Factor Α ◽  
P Type

P-type BiSbTe/RuO2 composite was fabricated using a combined process of melting and spark plasma sintering. The XRD patterns showed that RuO2 reacted with the matrix for the RuO2 content of 1.0 wt% and 4.0 wt% samples. The measured thermoelectric properties showed that the highest electrical conductivity was obtained for the sample with 2.0 wt% RuO2. The power factor (α2σ/κ) decreased with the increase of RuO2 below 450 K. The lattice thermal conductivity was lower than that of BiSbTe over the whole temperature range for BiSbTe/2.0 wt% RuO2.

A Study on the Vitrification Tests of the Low Level Radioactive Wastes Using Plasma Arc Melter System

2004 ◽  
Author(s):  
Boo Ho Yoon ◽  
Jae Hak Cho ◽  
Sang Chul Lee ◽  
Dong Woo Kang ◽  
Yong Joon Choi ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Nuclear Power ◽  
Power Plants ◽  
Radioactive Wastes ◽  
Plasma Arc ◽  
Micro Hardness ◽  
Radioactive Materials ◽  
Low Level ◽  
Glass Density ◽  
Glass Formulation

For the research on the vitrification of the low-level radioactive wastes (LLRW) produced in nuclear power plants, one pilot plant with plasma arc melter system was built and several tests were done on it. Some surrogate wastes, which were spiked with several materials and were made very similar to the real LLRW, were used for these tests. For the vitrification of the surrogate wastes, the surrogate wastes were classified into the combustible, the non-combustible and the resin. Then each waste was spiked with special materials and was melted in separate. Off-gases produced in each test were picked up and analyzed. Real radioactive materials cesium (Cs) and cobalt (Co) were spiked in each wastes. Data gained from the final glass formulation were follows. Glass density is 2.42 ∼ 2.95(g/cm3), the compressive strength is 30 ∼ 175 Mpa, micro hardness is 5.5 ∼ 5.8 Gpa. The leaching ratio for Co is 1.27×10−4 ∼ 1.08×10−3 (10mL/g) and that for Cs is 2.46×10−3 ∼ 3.23×10−2 (10mL/g). The leaching speed for Co is 4.14×10−7 ∼ 5.53×10−6 (g/m2) and that for Cs is 4.58×10−5 ∼ 3.87×10−4 (g/m2). In off-gas, dioxin & furan is 0.016 mano gram on the average, CO is about 20 ppm, NO2 is about 15 ppm and SO2 is about 15 ppm.

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