Research

11 pages, 944 KiB

Open AccessArticle

Properties of Controlled Low Strength Material with Circulating Fluidized Bed Combustion Ash and Recycled Aggregates

by Wei-Ting Lin, Tsai-Lung Weng, An Cheng, Sao-Jeng Chao and Hui-Mi Hsu

Materials 2018, 11(5), 715; https://0-doi-org.brum.beds.ac.uk/10.3390/ma11050715 - 02 May 2018

Cited by 29 | Viewed by 3483

This study aims to investigate the effect of adding circulating fluidized bed combustion (CFBC) ash, desulfurization slag, air-cooled blast-furnace slag and coal bottom ash to the controlled low-strength material (CLSM). Test methods include slump flow test, ball drop test, water soluble chloride ion [...] Read more.

This study aims to investigate the effect of adding circulating fluidized bed combustion (CFBC) ash, desulfurization slag, air-cooled blast-furnace slag and coal bottom ash to the controlled low-strength material (CLSM). Test methods include slump flow test, ball drop test, water soluble chloride ion content measurement, compressive strength and length change measurement. The results show that (1) the use of CFBC hydration ash with desulfurization slag of slump flow is the best, and the use of CFBC hydration ash with coal bottom ash and slump flow is the worst; (2) CFBC hydration ash with desulfurization slag and chloride ion content is the highest; (3) 24 h ball drop test (diameter ≤ 76 mm), and test results are 70 mm to 76 mm; (4) CFBC hydration ash with desulfurization slag and compression strength is the highest, with the coal bottom ash being the lowest; increase of CFBC hydration ash can reduce compressive strength; and (5) the water-quenched blast furnace slag and CFBC hydration ash would expand, which results in length changes of CLSM specimens. Full article

(This article belongs to the Special Issue Selected Papers from IMETI2016)

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8 pages, 1708 KiB

Open AccessArticle

Antibacterial Effects of Magnetically-Controlled Ag/Fe₃O₄ Nanoparticles

by Ming Chang, Wei-Siou Lin, Weihao Xiao and Yi-Ning Chen

Materials 2018, 11(5), 659; https://doi.org/10.3390/ma11050659 - 24 Apr 2018

Cited by 17 | Viewed by 3483

Abstract

This paper presents the use of a magnetic manipulation device to remotely control the movement of Ag/Fe₃O₄ nanoparticles (NPs) for enhancing the antibacterial effect of Ag particles in aqueous suspensions containing Escherichia coli (E. coli). The Ag/Fe₃ [...] Read more.

This paper presents the use of a magnetic manipulation device to remotely control the movement of Ag/Fe₃O₄ nanoparticles (NPs) for enhancing the antibacterial effect of Ag particles in aqueous suspensions containing Escherichia coli (E. coli). The Ag/Fe₃O₄ magnetic NPs were prepared by co-precipitation method where the Ag particles are simultaneously synthesized with the Fe₃O₄ particles to form Ag and Fe₃O₄ nanocomposite materials. The manipulation system utilized a homogeneous rotating magnetic field to carry out magnetic stirring of NPs in the petri dishes containing bacterial suspensions. The optimum magnetron parameters and best antibacterial effects were implemented with six different concentrations from 0.6 wt % to 6.6 wt % of the NPs at driving frequencies from 50 rpm to 200 rpm for 3 min. The highest antibacterial effect of 99.4% was achieved at 5.4 wt % of NPs and the driving frequency of 100 rpm. A time-dependent antibacterial effect in 0.1 wt % of Ag/Fe₃O₄ was also observed. The results indicate that the use of specific rotating magnetic fields to manipulate Ag/Fe₃O₄ magnetic NPs can significantly improve the antibacterial efficacy. Due to the good biocompatibility of the Ag NPs, the presented technique can be applied to clean water resources in the future. Full article

(This article belongs to the Special Issue Selected Papers from IMETI2016)

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11 pages, 5917 KiB

Open AccessArticle

Contact Behavior of Composite CrTiSiN Coated Dies in Compressing of Mg Alloy Sheets under High Pressure

by T.S. Yang, S.H. Yao, Y.Y. Chang and J.H. Deng

Materials 2018, 11(1), 88; https://0-doi-org.brum.beds.ac.uk/10.3390/ma11010088 - 08 Jan 2018

Cited by 2 | Viewed by 3639

Abstract

Hard coatings have been adopted in cutting and forming applications for nearly two decades. The major purpose of using hard coatings is to reduce the friction coefficient between contact surfaces, to increase strength, toughness and anti-wear performance of working tools and molds, and [...] Read more.

Hard coatings have been adopted in cutting and forming applications for nearly two decades. The major purpose of using hard coatings is to reduce the friction coefficient between contact surfaces, to increase strength, toughness and anti-wear performance of working tools and molds, and then to obtain a smooth work surface and an increase in service life of tools and molds. In this report, we deposited a composite CrTiSiN hard coating, and a traditional single-layered TiAlN coating as a reference. Then, the coatings were comparatively studied by a series of tests. A field emission SEM was used to characterize the microstructure. Hardness was measured using a nano-indentation tester. Adhesion of coatings was evaluated using a Rockwell C hardness indentation tester. A pin-on-disk wear tester with WC balls as sliding counterparts was used to determine the wear properties. A self-designed compression and friction tester, by combining a Universal Testing Machine and a wear tester, was used to evaluate the contact behavior of composite CrTiSiN coated dies in compressing of Mg alloy sheets under high pressure. The results indicated that the hardness of composite CrTiSiN coating was lower than that of the TiAlN coating. However, the CrTiSiN coating showed better anti-wear performance. The CrTiSiN coated dies achieved smooth surfaces on the Mg alloy sheet in the compressing test and lower friction coefficient in the friction test, as compared with the TiAlN coating. Full article

(This article belongs to the Special Issue Selected Papers from IMETI2016)

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4001 KiB

Open AccessArticle

Effect of Relative Humidity on Adsorption Breakthrough of CO₂ on Activated Carbon Fibers

by Yu-Chun Chiang, Yu-Jen Chen and Cheng-Yen Wu

Materials 2017, 10(11), 1296; https://0-doi-org.brum.beds.ac.uk/10.3390/ma10111296 - 11 Nov 2017

Cited by 49 | Viewed by 7397

Abstract

Microporous activated carbon fibers (ACFs) were developed for CO₂ capture based on potassium hydroxide (KOH) activation and tetraethylenepentamine (TEPA) amination. The material properties of the modified ACFs were characterized using several techniques. The adsorption breakthrough curves of CO₂ were measured and [...] Read more.

Microporous activated carbon fibers (ACFs) were developed for CO₂ capture based on potassium hydroxide (KOH) activation and tetraethylenepentamine (TEPA) amination. The material properties of the modified ACFs were characterized using several techniques. The adsorption breakthrough curves of CO₂ were measured and the effect of relative humidity in the carrier gas was determined. The KOH activation at high temperature generated additional pore networks and the intercalation of metallic K into the carbon matrix, leading to the production of mesopore and micropore volumes and providing access to the active sites in the micropores. However, this treatment also resulted in the loss of nitrogen functionalities. The TEPA amination has successfully introduced nitrogen functionalities onto the fiber surface, but its long-chain structure blocked parts of the micropores and, thus, made the available surface area and pore volume limited. Introduction of the power of time into the Wheeler equation was required to fit the data well. The relative humidity within the studied range had almost no effects on the breakthrough curves. It was expected that the concentration of CO₂ was high enough so that the impact on CO₂ adsorption capacity lessened due to increased relative humidity. Full article

(This article belongs to the Special Issue Selected Papers from IMETI2016)

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4813 KiB

Open AccessArticle

Effect of Wafer Level Underfill on the Microbump Reliability of Ultrathin-Chip Stacking Type 3D-IC Assembly during Thermal Cycling Tests

by Chang-Chun Lee

Materials 2017, 10(10), 1220; https://0-doi-org.brum.beds.ac.uk/10.3390/ma10101220 - 24 Oct 2017

Cited by 9 | Viewed by 6729

Abstract

The microbump (μ-bump) reliability of 3D integrated circuit (3D-IC) packaging must be enhanced, in consideration of the multi-chip assembly, during temperature cycling tests (TCT). This research proposes vehicle fabrications, experimental implements, and a nonlinear finite element analysis to systematically investigate the assembled packaging [...] Read more.

The microbump (μ-bump) reliability of 3D integrated circuit (3D-IC) packaging must be enhanced, in consideration of the multi-chip assembly, during temperature cycling tests (TCT). This research proposes vehicle fabrications, experimental implements, and a nonlinear finite element analysis to systematically investigate the assembled packaging architecture that stacks four thin chips through the wafer level underfill (WLUF) process. The assembly of μ-bump interconnects by daisy chain design shows good quality. Results of both TCT data and the simulation indicate that μ-bumps with residual SnAg solders can reach more than 1200 fatigue life cycles. Moreover, several important design factors in the present 3D-IC package influence μ-bump reliability. Analytical results show that the μ-bump’s thermo-mechanical reliability can be improved by setting proper chip thickness, along with a WLUF that has a low elastic modulus and a small coefficient of thermal expansion. Full article

(This article belongs to the Special Issue Selected Papers from IMETI2016)

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7250 KiB

Open AccessArticle

Antibacterial and Tribological Performance of Carbonitride Coatings Doped with W, Ti, Zr, or Cr Deposited on AISI 316L Stainless Steel

by Sun-Hui Yao, Yen-Liang Su and Yu-Cheng Lai

Materials 2017, 10(10), 1189; https://0-doi-org.brum.beds.ac.uk/10.3390/ma10101189 - 17 Oct 2017

Cited by 13 | Viewed by 4213

Abstract

Carbonitride (CNx) coatings have existed for several decades but are not well understood. Related studies have indicated that CNx coatings exhibit behaviors comparable to diamond-like carbon (DLC) coatings. Metal-doped CNx coatings are expected to show superior performance to single CNx coatings. In this [...] Read more.

Carbonitride (CNx) coatings have existed for several decades but are not well understood. Related studies have indicated that CNx coatings exhibit behaviors comparable to diamond-like carbon (DLC) coatings. Metal-doped CNx coatings are expected to show superior performance to single CNx coatings. In this study, a CNx coating and a group of CNx coatings with 6 at. % metal doping (W, Ti, Zr, or Cr) were prepared on biograde AISI 316L stainless steel (SS316L) substrates, and they were then characterized and studied for antibacterial and wear performance. The microstructure, constituent phase, nanohardness, adhesion, surface roughness, and contact angle were evaluated. The antimicrobial test used Staphylococcus aureus and followed the Japanese Industrial Standard JIS Z 2801:2010. Finally, the wear behavior was assessed. The results showed that the CNx coating was a composite of amorphous CNx and amorphous C structures. The metal doping caused crystalline metal carbides/nitrides to form in the CNx coatings, which weakened their overall integrity. All the coatings showed antimicrobial ability for the SS316L samples. The CNx-Zr coating, the surface of which had the highest hydrophilicity, produced the best antibacterial performance. However, the CNx-Zr coating showed lower wear resistance than the CNx-W and CNx-Ti coatings. The CNx-Ti coating with a highly hydrophilic surface exhibited the lowest antibacterial ability. Full article

(This article belongs to the Special Issue Selected Papers from IMETI2016)

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4402 KiB

Open AccessArticle

Tribological Performance of Green Lubricant Enhanced by Sulfidation IF-MoS₂

by Shih-Chen Shi

Materials 2016, 9(10), 856; https://0-doi-org.brum.beds.ac.uk/10.3390/ma9100856 - 21 Oct 2016

Cited by 36 | Viewed by 5767

Abstract

Biopolymers reinforced with nanoparticle (NP) additives are widely used in tribological applications. In this study, the effect of NP additives on the tribological properties of a green lubricant hydroxypropyl methylcellulose (HPMC) composite was investigated. The IF-MoS₂ NPs were prepared using the newly [...] Read more.

Biopolymers reinforced with nanoparticle (NP) additives are widely used in tribological applications. In this study, the effect of NP additives on the tribological properties of a green lubricant hydroxypropyl methylcellulose (HPMC) composite was investigated. The IF-MoS₂ NPs were prepared using the newly developed gas phase sulfidation method to form a multilayered, polyhedral structure. The number of layers and crystallinity of IF-MoS₂ increased with sulfidation time and temperature. The dispersity of NPs in the HPMC was investigated using Raman and EDS mapping and showed great uniformity. The use of NPs with HPMC enhanced the tribological performance of the composites as expected. The analysis of the worn surface shows that the friction behavior of the HPMC composite with added NPs is very sensitive to the NP structure. The wear mechanisms vary with NP structure and depend on their lubricating behaviors. Full article

(This article belongs to the Special Issue Selected Papers from IMETI2016)

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2355 KiB

Open AccessArticle

Corrosion Inhibition of High Speed Steel by Biopolymer HPMC Derivatives

by Shih-Chen Shi and Chieh-Chang Su

Materials 2016, 9(8), 612; https://0-doi-org.brum.beds.ac.uk/10.3390/ma9080612 - 23 Jul 2016

Cited by 32 | Viewed by 5510

Abstract

The corrosion inhibition characteristics of the derivatives of biopolymer hydroxypropyl methylcellulose (HPMC), hydroxypropyl methylcellulose phthalate (HPMCP), and hydroxypropyl methylcellulose acetate succinate (HPMCAS) film are investigated. Based on electrochemical impedance spectroscopic measurements and potentiodynamic polarization, the corrosion inhibition performance of high speed steel coated [...] Read more.

The corrosion inhibition characteristics of the derivatives of biopolymer hydroxypropyl methylcellulose (HPMC), hydroxypropyl methylcellulose phthalate (HPMCP), and hydroxypropyl methylcellulose acetate succinate (HPMCAS) film are investigated. Based on electrochemical impedance spectroscopic measurements and potentiodynamic polarization, the corrosion inhibition performance of high speed steel coated with HPMC derivatives is evaluated. The Nyquist plot and Tafel polarization demonstrate promising anti-corrosion performance of HPMC and HPMCP. With increasing film thickness, both materials reveal improvement in corrosion inhibition. Moreover, because of a hydrophobic surface and lower moisture content, HPMCP shows better anti-corrosion performance than HPMCAS. The study is of certain importance for designing green corrosion inhibitors of high speed steel surfaces by the use of biopolymer derivatives. Full article

(This article belongs to the Special Issue Selected Papers from IMETI2016)

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