scholarly journals Morphology of Aluminum Alloy Foams Produced with Dolomite via Partial Sintering of Precursors

Materials ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1691 ◽  
Author(s):  
Ana Maria Medina Ramirez ◽  
Ramona Roxana Vintila ◽  
Robin A. L. Drew

Highly expanded, low-cost aluminum-based foams were successfully produced via powder metallurgy using dolomite as foaming agent. Nickel additions (5–15 wt.%) were explored in order to reduce the temperature disparity between dolomite decomposition and the melting range of the metallic matrix. Specific Al–Ni compositions provide appropriate viscosities for effective encapsulation of CO2 gas released during dolomite decomposition. A partial sintering step of compacted precursors was introduced prior to foaming, which resulted in high porosity levels (~86%) and significant volume expansion (~250%) in the final product. The partial sintering technique was a key determining factor in obtaining stable, highly expanded cellular structures with homogeneous pores, averaging 3 mm in size and being morphologically comparable with ALPORASTM foams.

RSC Advances ◽  
2017 ◽  
Vol 7 (51) ◽  
pp. 32288-32293 ◽  
Author(s):  
Chen Wang ◽  
Junfeng Li ◽  
Handong Jiao ◽  
Jiguo Tu ◽  
Shuqiang Jiao

A novel Al-ion battery based on an Al alloy anode, pyrolytic graphite paper cathode, and low-cost AlCl3–urea liquid analogue electrolyte was successfully established. The present Al alloy/PG battery can afford a capacity as high as 105 mA h g−1.


2021 ◽  
Vol 17 ◽  
Author(s):  
Linyu Wang ◽  
Shasha Hong ◽  
Yuxi Yang ◽  
Yonghai Song ◽  
Li Wang

Background: In recent years, electrochemical sensors are widely preferred because of their high sensitivity, rapid response, low cost and easy miniaturization. Covalent organic frameworks (COFs), a porous crystalline polymer formed by organic units connected by covalent bonds, have been widely used in gas adsorption and separation, drug transportation, energy storage, photoelectric catalysis, electrochemistry and other aspects due to their large specific surface, excellent stability, high inherent porosity, good crystallinity as well as structural and functional controllability. The topological structure of COFs can be designed in advance, the structural units and linkage are diversified, and the structure is easy to be functionalized, which are all beneficial to their application in electrochemical sensors. Methods: The types, synthesis methods, properties of covalent organic frameworks and some examples of using covalent organic frameworks in electrochemical sensors are reviewed. Results: Due to their characteristics of a large specific surface, high porosity, orderly channel and periodically arranged π electron cloud, COFs are often used to immobilize metal nanoparticles, aptamers or other materials to achieve the purpose of building electrochemical sensors with high sensitivity and good stability. Since the structure of COFs can be predicted, different organic units can build COFs with different structures and properties. Therefore, organic units with certain functional groups can be selected to build COFs with certain properties and used directly for electrochemical sensors. Conclusion: COFs have a good application prospect in electrochemical sensors.


2018 ◽  
Vol 280 ◽  
pp. 270-276 ◽  
Author(s):  
Mohamad Saed Hussein ◽  
Teh Pei Leng ◽  
Abdul Razak Rahmat ◽  
Firuz Zainuddin ◽  
Yeoh Chow Keat

This research studied the effect of sodium bicarbonate content on the properties of epoxy. Sodium bicarbonate (SB) was used as foaming agent to improve the properties of thermosetting epoxy resin. The samples of epoxy foam were produced using mixing method. Sodium bicarbonate was selected as blowing agent by reason of the environmental friendly and low cost concern. Mechanical, physical and morphology properties were done. Sodium bicarbonate content was varied at 5, 10, 15, 20 and 25 part per hundred (phr), respectively. It can be highlighted that the optimum content of the SB was selected at 15 phr and it gave the moderate porosity percentage (%), and moderate value in mechanical and density properties, higher SB content exhibited lower flexural properties.


2013 ◽  
Vol 2013 (CICMT) ◽  
pp. 000020-000025
Author(s):  
Hélène DEBEDA ◽  
Riadh LAKHMI ◽  
Isabelle FAVRE ◽  
Jonathan ARGILLOS ◽  
Mario MAGLIONE ◽  
...  

Using the association of the low-cost screen-printing technology with the sacrificial layer method, the feasibility of totally released piezoelectric thick-films microceramics of gold electroded PZT type is studied. After the deposition of the sacrificial layer on an alumina substrate and subsequent printing and drying of gold, PZT and gold layers, the final firing is performed at low temperature. This is followed by the releasing step of the Au/PZT/Au in diluted acidic solution. Impedance analysis shows that the electrical properties and electromechanical coefficients of poled PZT thick-films are still lower than those of PZT ceramics. This result is correlated to the high porosity rate of the PZT layer. However these piezoelectric microceramics present a good electromechanical behaviour and can be used as sensors when solicited by vibrations or as actuators to generate vibrations in a structure on which they are bonded. Moreover, the successful fabrication associated to a good electromechanical signature on a metallic test structure suggests Structural Health Monitoring applications.


2015 ◽  
Vol 60 (2) ◽  
pp. 1523-1527 ◽  
Author(s):  
M. Suśniak ◽  
J. Karwan-Baczewska ◽  
J. Dutkiewicz ◽  
M. Actis Grande ◽  
M. Rosso

Abstract The present work investigates the possibility of using powder metallurgy processing for producing a metal matrix composite. Materials were prepared from AlSi5Cu2 chips with reinforcement of 10, 15, 20 wt. % silicon carbide. Aluminum alloy chips were milled with SiC powder in a high-energy ball mill by 40 hours. Mechanical alloying process lead to obtain an uniform distribution of hard SiC particles in the metallic matrix and refine the grain size. The consolidation of composite powders was performed by vacuum hot pressing at 450°C, under pressure of 600 MPa by 10 min. The results shows that the addition of SiC particles has a substantial influence on the microstructure and mechanical properties of composite powder as well as consolidated material. Hot pressing is an effective consolidation method which leads to obtain dense AlSi5Cu2/SiC composite with homogeneous structure and advanced mechanical properties.


2014 ◽  
Vol 618 ◽  
pp. 140-145
Author(s):  
Yang Liu ◽  
Ren Zhang ◽  
En Quan Liang ◽  
Dong Li ◽  
Ying Chen ◽  
...  

The history of GLARE laminate was introduced. Through comparison with conventional aluminum alloy sheets, the excellent performance of GLARE as a new generation aeronautic material is discussed. The properties and application of GLARE in large civil aircraft indicates that new composite materials such as GLARE will replace bulk aluminum alloy in future aircraft structure. With the continuous development of material technologies, a trend of developing high strength and low cost composite materials will lead aviation industry to a new stage.


CORROSION ◽  
10.5006/2815 ◽  
2018 ◽  
Vol 74 (9) ◽  
pp. 1023-1032
Author(s):  
Dannisa R. Chalfoun ◽  
Mariano A. Kappes ◽  
Mauricio Chocrón ◽  
Raul B. Rebak

Aluminum alloy UNS A95052 (AA5052) is very attractive for desalination applications because of its good corrosion resistance in seawater at temperatures up to 125°C, low cost, good thermal conductivity, and non-toxicity of its corrosion products. The pitting corrosion potential, Epit, and the pit repassivation potential, Er,pit, of AA5052 were measured in deaerated 65,000 ppm sodium chloride (NaCl) solutions at 30°C, 60°C, and 85°C. Epit decreased with temperature, in accord with literature results. Er,pit was a function of anodic charge passed during pit growth stage. A complete evaluation of suitability of this alloy from a corrosion perspective requires also studies of crevice corrosion at different temperatures, considering that multi-plate designs of desalinators have metal plates in contact with rubber gaskets and seals. Cyclic potentiodynamic polarization was used to estimate crevice repassivation potentials, Er,crev, at 30°C, 60°C, and 85°C, in specimens with an attached rubber O-ring as a crevice former. This crevice former simulated the partially occluded geometry expected in desalination plants. Stable crevice corrosion potentials, Ecrev, were similar to Epit, and, when polarized to a similar anodic charge density, Er,crev were similar to Er,pit. Based on this result, from a corrosion perspective, the presence of crevices in the desalination plant is not expected to present an additional risk during operation of the plant. Electrochemical tests were also performed in saturated AlCl3 solutions to explain the results using Galvele’s localized acidification model.


Agriculture ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 114 ◽  
Author(s):  
Wen-Tien Tsai ◽  
Chien-Hung Hsu ◽  
Yu-Quan Lin

The use of biochar in the horticulture and crop fields is a recent method to improve soil fertility due to its porous features and rich nutrients. In the present study, dairy manure (DM) was used as a biomass precursor in the preparation of highly porous biochar (DM-BC) produced at specific conditions. Based on N2 adsorption-desorption isotherms and scanning electron microscopy (SEM) observations, the resulting biochar featured its microporous/mesoporous textures with a BET surface area of about 300 m2/g and total pore volume of 0.185 cm3/g, which could be a low-cost biosorbent for the effective removal of methylene blue (MB) from the aqueous solution. As observed by the energy dispersive X-ray spectroscopy (EDS), the primary inorganic nutrients on the surface of DM-BC included calcium (Ca), magnesium (Mg), potassium (K), phosphorus (P), silicon (Si), sulfur (S), sodium (Na) and aluminum (Al). Furthermore, the resulting biochar was investigated in duplicate for its biosorption performance of cationic compound (i.e., methylene blue, MB) from the aqueous solution with various initial MB concentrations and DM-BC dosages at 25 °C. The findings showed that the biosorption kinetic parameters fitted by the pseudo-second order rate model with high correlations were consistent with its porous features. These experimental results suggested that the porous DM-based biochar could be reused as a biosorbent, biofertilizer, or soil amendments due to the high porosity and the abundance in nutrient minerals.


Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3463
Author(s):  
Xin Wang ◽  
Xiaoyong Tian ◽  
Lixian Yin ◽  
Dichen Li

A novel 3D printing route to fabricate continuous fiber reinforced metal matrix composite (CFRMMC) is proposed in this paper. It is distinguished from the 3D printing process of polymer matrix composite that utilizes the pressure inside the nozzle to combine the matrix with the fiber. This process combines the metallic matrix with the continuous fiber by utilizing the wetting and wicking performances of raw materials to form the compact internal structures and proper fiber-matrix interfaces. CF/Pb50Sn50 composites were printed with the Pb50Sn50 alloy wire and modified continuous carbon fiber. The mechanical properties of the composite specimens were studied, and the ultimate tensile strength reached 236.7 MPa, which was 7.1 times that of Pb50Sn50 alloy. The fracture and interfacial microstructure were investigated and analyzed. The relationships between mechanical properties and interfacial reactions were discussed. With the optimized process parameters, several composites parts were printed to demonstrate the advantages of low cost, short fabrication period and flexibility in fabrication of complex structures.


2014 ◽  
Vol 989-994 ◽  
pp. 270-275
Author(s):  
Jian Jun Fang ◽  
Yun Jing Song ◽  
Zhuo Xin Li

The research uses electric arc spraying with low cost and convenient operation to prepare four TiB2 particle reinforced composite coatings with high bonding strength and uniform tissue. It makes comparative study on elevated temperature erosion actions of coating and 45CT of electric arc spraying. The results indicate the coating has excellent erosion wearing resistance. TiB2 particles in M-TiB2 coating have small size, have good unity with metallic matrix, and are distributed on metallic matrix with high hardness relatively uniformly, and porosity of coating is low. The coating has excellent erosion resistance.


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