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Influence of Al2O3 addition on the hardness and in vitro corrosion behavior of laser synthesized Ti-Al2O3 coatings on Ti-6Al-4V
摘要： Titanium alloy (Ti-6Al-4V) has been mostly used for medical implants due to its good chemical and mechanical properties. However, this alloy has tendency to emanate toxic V and Al due to its low corrosion resistance in body conditions. In this work, an experimental study of laser cladding Ti-Al2O3 coatings with different Al2O3 fractions (5 wt.% Al2O3, 8 wt.% Al2O3, and 10 wt.% Al2O3) was carried out to establish a coating which could improve the hardness and corrosion resistance of Ti-6Al-4V alloy. Laser parameters of 900 W power, 0.6 m/min laser scan speed, and 2 l/min powder feed were used in this research. The microstructure, phase constituents, microhardness, and corrosion of the resultant coatings were characterized by scanning electron microscope (SEM), optical microscope (OPM), X-Ray Diffractometer (XRD), Vicker hardness tester, and potentiostat respectively. Results showed that a defect free coating was achieved at a coating with less Al2O3 content. Increase in Al2O3 addition resulted in increment of hardness with Ti-10 wt.% Al2O3 coating achieving an optimum hardness of about 2.2 times greater than that of the substrate. Moreover, considerable increment in corrosion resistance of Ti-6Al-4Valloy was achieved after laser deposition of various Ti-Al2O3 admixed coatings. An optimal corrosion rate reduction of about 81% and polarization resistance increment of 709% over the substrate were achieved at Ti-5 wt.% Al2O3 due to low porosity within the coating layer. It has been established that fabricating Ti-Al2O3 on Ti6Al4V through laser could be used in improving the surface hardness values and corrosion resistance.
关键词： Ti-Al2O3 coatings,Corrosion behavior,Laser cladding,Hardness properties,Ti-6Al-4Valloy
更新于2025-09-19 17:15:36
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Recent Developments about Conductive Polymer Based Composite Photocatalysts
摘要： Conductive polymers have been widely investigated in various applications. such as polyaniline (PANI), polypyrrole (PPy), poly(3,4-ethylenedioxythiophene) (PEDOT)), and polythiophene (PTh) have been loaded with various semiconductor nanomaterials to prepare the composite photocatalysts. However, a critical review of conductive polymer-based composite photocatalysts has not been available yet. Therefore, in this review, we summarized the applications of conductive polymers in the preparation of composite photocatalysts for photocatalytic degradation of hazardous chemicals, antibacterial, and photocatalytic hydrogen production. Various materials were systematically surveyed to illustrate their preparation methods, morphologies, and photocatalytic performances. The synergic effect between conductive polymers and semiconductor nanomaterials were observed for a lot of composite photocatalysts. The band structures of the composite photocatalysts can be analyzed to explain the mechanism of their enhanced photocatalytic activity. The incorporation of conductive polymers can result in signi?cantly improved visible-light driven photocatalytic activity by enhancing the separation of photoexcited charge carriers, extending the light absorption range, increasing the adsorption of reactants, inhibiting photo-corrosion, and reducing the formation of large aggregates. This review provides a systematic concept about how conductive polymers can improve the performance of composite photocatalysts.
关键词： synergic effect,degradation,photo-corrosion,photogenerated electron,antibacterial,hydrogen production,photocatalyst,conductive polymer
更新于2025-09-19 17:15:36
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Tackling conservation challenges using erbium lasers: case studies at the British Museum
摘要： Research was conducted at the British Museum to investigate the potential of Er:YAG lasers to address challenging conservation problems where traditional conservation methods had failed. The approach followed was to perform laser tests on model samples and unregistered objects to determine the laser alteration threshold fluence on each substrate and the ability of the laser to remove contaminants, such as inorganic crusts and organic coatings. The effects of the laser were assessed by means of optical microscopy, scanning electron microscopy and colour measurements. If tests were successful on the samples and unregistered objects, the laser was then used on artefacts from the collection of the British Museum. This article details the successful results obtained using Er:YAG lasers for the removal of corrosion from metals, remains of old adhesives from ceramics and shells, mould from polychromed limestone and terracotta, modern overpainting and varnish from a fresco painting.
关键词： Er:YAG laser cleaning,coatings,overpainting,mould,alteration threshold,corrosion
更新于2025-09-19 17:13:59
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POST WELD HEAT TREATMENT OF NiTinol SHAPE MEMORY ALLOY USING LASER POWER SOURCE
摘要： In this work, attempt is made to carry out post weld heat treatment (PWHT) on NiTinol samples using laser power source. Initially, 1 mm thick NiTinol sheets were welded in butt joint position using Ytterbium: Yttrium aluminum garnet (Yb: YAG) laser power source. Laser welding was carried out in continuous mode, and the quality of the weld was assessed with respect to phase transformation temperatures, microhardness, tensile strength, and corrosion resistance. To improve the quality of the welded samples, PWHT was done by passing a laser beam over the welded samples. It was found that PWHT had a significant effect on the phase transformation temperatures, microhardness, tensile strength and corrosion behavior of the welded NiTinol joints.
关键词： laser heat treatment,NiTinol,laser welding,mechanical properties,corrosion behavior
更新于2025-09-19 17:13:59
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An Influence of the Module Structure on Reliability of Crystalline Silicon Solar Cells
摘要： To investigate the influence of the difference in module structures on the degradation of crystalline silicon solar cells, two different photovoltaic modules were fabricated, and a high-temperature and high-humidity test was carried out. The degradation modes of these modules were compared to each other using electrical characteristics and electroluminescence images. Degradation of outputs occurred in both modules, and different degradation modes were confirmed by electroluminescence images. The difference in degradation modes between these modular structures could be due to the difference in concentration distribution attributable to the moisture and acetic acid generated from the encapsulant inside the module.
关键词： Moisture Ingress,Metallization,Damp Heat Test,Corrosion,Aluminum,Photovoltaic Module,Silver Paste
更新于2025-09-19 17:13:59
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Study on laser cladding and properties of AZ63-Er alloy for automobile engine
摘要： Aiming at the problem of the poor corrosion resistance of magnesium alloys for automobiles, Al-TiC and Al-TiC-Y2O3 cladding layers were prepared on the AZ63-Er alloy by laser cladding technology, studied the effects of Al:TiC mass ratio and Y2O3 addition on the microstructure, phase composition, hardness and corrosion resistance of the cladding layer. The results show that the Al-TiC laser cladding layer with different mass ratios has metallurgical bonding with AZ63-Er alloy substrate, and there are no pores or cracks at the interface. The main phases of the Al-TiC laser cladding layer are Ti3AlC, TiC, Mg2Al3, Al3Mg2, Al, Mg, AlMg and Ti6O. The hardness of laser cladding layer with the mass ratios of Al:TiC are 8:1, 4:1 and 2:1 are about 2.75, 3.24 and 3.94 times of the substrate. The corrosion resistance of Al-TiC cladding layer is higher than that of the AZ63-Er alloy substrate, and the corrosion resistance of the Al:TiC cladding layer with the mass ratio of 8:1 is the best. Al3Y and Al4MgY phases are formed in the Al-TiC-Y2O3 cladding layer after Y2O3 addition. The hardness of the Al-TiC-Y2O3 cladding layer is significantly higher than that of the Al-TiC cladding layer. The Al-TiC-Y2O3 composite cladding layer has the best hardness and corrosion resistance when the Y2O3 content is 0.6%.
关键词： surface modification,laser cladding,hardness,AZ63-Er alloy,corrosion resistance
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Understanding CdTe Performance with Engineered Front and Back Interfaces
摘要： Recently, structural health monitoring (SHM) using radio frequency identification (RFID) tag antenna-based sensing (TABS) has received increasing attention because of its wireless, passive, and low-cost characteristics. However, a great challenge in the SHM using RFID TABS is multiple influences in the measurement. This paper presents an ultrahigh frequency RFID sensor system for corrosion detection and characterization. In this paper, a 3-D antenna sensor is designed to work on the surface of a protective coated steel sample. Sweep-frequency measurements are applied for analog identifier with principal component analysis (PCA) to overcome the multiple influences from reader-tag orientation, distance, and environment. Feature extraction and selection though PCA can get robust and sensitive defect information by projecting the test data into an orthogonal feature space. The test results demonstrate that the proposed method can be applied to detect and characterize early-stage corrosion in metals.
关键词： principal component analysis (PCA),radio frequency identification (RFID),structural health monitoring (SHM),Antenna sensor,corrosion detection
更新于2025-09-19 17:13:59
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Influence of Powder Condition on Surface Properties of Cold-Resistant High-Strength Steel Produced by Direct Laser Deposition Method
摘要： Direct laser deposition (DLD) allows creating parts of complex shapes and configurations in a single process step without using of additional equipment. Such technologies are required in the shipbuilding industry, aircrafts, gas turbines, mechanical engineering etc., where it is necessary to manufacture large-sized and complex products that have a long technological cycle for production using classical technologies. DLD makes it possible to produce parts of various alloys with mechanical characteristics at the level of the wrought alloys. The publication is described direct laser deposition of high-strength cold-resistant steels results. Besides mechanical properties of material, the exploitation properties of the structure are also significantly important. Results of corrosion, abrasive-corrosion and tribotechnical tests are shown.
关键词： corrosion resistance,high-strength steel,abrasive-corrosion resistance,Direct laser deposition,cold-resistant steel,initial powder condition,wear resistance
更新于2025-09-16 10:30:52
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Palladium Nanocubes Synthesized Via - Metal Chloride Route for Dye Sensitized Solar Cells (DSSC) Applications
摘要： Palladium nanocubes (Pd NCs) were synthesized using metal chloride route. The morphology of the electrode is observed by scanning electron microscopy and transmission electron microscopy. Energy dispersive spectra analysis confirms the palladium material. The phase purity of the synthesized palladium nanocubes was investigated through X-Ray Diffraction (XRD) analysis and the obtained pattern was compared with JCPDS data. The Photovoltaic performance of the DSSC with palladium counter electrode is being investigated.
关键词： Counter electrode,Catalytic activity,Corrosion
更新于2025-09-16 10:30:52
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Mechanism of silver/glass interaction in the metallization of crystalline silicon solar cells
摘要： In order to reveal the interaction between solid substances (Ag powder and glass frit) during the metallization of crystalline silicon solar cells, the effect of glass frit on the Ag powder sintering and the mechanism of Ag colloid formation in glass phase were investigated. The results show that the Ag powder could grow into larger grains as mixed with a certain amount of glass frit, because the corrosion of Ag by glass melt enabled early start of Ag sintering. This makes the internal grain size and electric resistivity of sintered Ag lines to be closely related to the glass content in the silver paste. Subsequently, it was found that the formation of Ag colloid in glass phase is a physical process rather than a chemical transformation process. Taking Pb-B-Zn-Al composite oxide glasses for exemplification, a feasible strategy of raising the solubility of Ag in glass melt is proposed.
关键词： silver colloid formation,solid interaction mechanism,metallization,glass corrosion effect,silicon solar cells
更新于2025-09-16 10:30:52