Effect of Li on Corrosion Resistance of Nearly Eutectic Al-Si Casting Alloys

2013 ◽  
Vol 364 ◽  
pp. 573-576
Author(s):  
Yuan Xing Cai ◽  
Zhong Kui Zhao ◽  
Zhi Gang Wang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Corrosion Resistance ◽  
Energy Dispersive Spectrometer ◽  
Lithium Content ◽  
Corrosion Performance ◽  
Surface Appearance ◽  
Tafel Polarization ◽  
Casting Alloys ◽  
Scanning Electron

Lithium was added into ZAlSi12 casting alloys to produce Al-Si-Li alloys containing 0%Li, 1%Li, 2%Li and 3%Li respectively. The corrosion performance of the alloys containing various content of lithium was tested by the Tafel polarization curves and the alloys were dipped thoroughly into the solution of 5% NaCl. The surface appearance of the alloys after corrosion was observed by Scanning Electron Microscopy, the composition of corrosion products was determined by Energy Dispersive Spectrometer. The results show that the corrosion resistance of ZAlSi12 casting alloys is improved by the addition of lithium. The alloy has an optimum corrosion resistance when the lithium content is 2%, and then the corrosion resistance decreases as increment of lithium content.

The Study of Electroless Ni-B Coating on 45 Steel

2012 ◽  
Vol 501 ◽  
pp. 185-189
Author(s):  
Jian Zhang Guo ◽  
Qian Liu
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Corrosion Resistance ◽  
Energy Dispersive Spectrometer ◽  
Salt Spray ◽  
High Hardness ◽  
Experimental Results ◽  
Electroless Ni ◽  
Scanning Electron ◽  
Optimal Formula

In order to improve the corrosion resistance and the hardness of the 45 steel, under comparison tests, the electroless Ni-B was prepared on the 45 steel. We made a contrast test to get the optimal formula. The coating under the optimal formula was characterized by Scanning Electron Microscopy(SEM), Energy Dispersive Spectrometer(EDS), metallurgical microscope and salt spray cabinet. The experimental results showed that the electroless Ni-B coating on 45 steel was low boron coating, with high hardness, and the hardness of the coating could catch HV524; the thickness of the coating was 16μm.

Microstructure Investigations of Streak Formation in 6063 Aluminum Extrusions by Optical Metallographic Techniques

2013 ◽  
Vol 19 (2) ◽  
pp. 276-284 ◽  
Author(s):  
George Vander Voort ◽  
Beatriz Suárez-Peña ◽  
Juan Asensio-Lozano
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Particle Size ◽  
Hot Extrusion ◽  
Magnesium Silicide ◽  
Precipitation Strengthening ◽  
Surface Appearance ◽  
Aluminum Extrusions ◽  
Extruded Products ◽  
Scanning Electron

AbstractThe present study investigates the effect of the solidification strategy for AA 6063 alloy on the surface appearance of anodized extrusions. The microstructure of the samples was analyzed using both light optical microscopy and scanning electron microscopy. Results show that if heavy segregation occurs from rapid solidification, coarse Mg2Si particles form, thus reducing the potential for precipitation strengthening by the finer β-Mg2Si developed in the solid state. Differentially-strained regions formed during hot extrusion induce differences in particle size for magnesium silicide (Mg2Si) precipitates. Anodizing generates surface roughness due to Mg2Si particle dissolution and AlFeSi decohesion, which is related to both particle size and deformation. During anodizing, an oxide layer forms on the surface of the extruded products, which can lead to streak formation, usually a subject of rejection due to unacceptable heterogeneous reflectivity.

Influence of Fly Ash on Corrosion Resistance of Refractory Forsterite-Spinel Ceramics

2021 ◽  
Vol 325 ◽  
pp. 181-187
Author(s):  
Martin Nguyen ◽  
Radomír Sokolář
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Corrosion Resistance ◽  
Fly Ash ◽  
Raw Materials ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transition Zones ◽  
Refractory Ceramics ◽  
Scanning Electron

This article examines the influence of fly ash on corrosion resistance of refractory forsterite-spinel ceramics by molten iron as a corrosive medium. Fly ash in comparison with alumina were used as raw materials and sources of aluminium oxide for synthesis of forsterite-spinel refractory ceramics. Raw materials were milled, mixed in different ratios into two sets of mixtures and sintered at 1550°C for 2 hours. Samples were characterized by X-ray diffraction analysis and thermal dilatometric analysis. Crucibles were then made from the fired ceramic mixtures and fired together with iron at its melting point of 1535°C for 5 hours. The corrosion resistance was evaluated by scanning electron microscopy on the transition zones between iron and ceramics. Mixtures with increased amount of spinel had higher corrosion resistance and mixtures with fly ash were comparable to mixtures with alumina in terms of corrosion resistance and refractory properties.

Effect of KBF4 Addition on the Microstructure of Mg-6Zn-1Si Alloy

2012 ◽  
Vol 535-537 ◽  
pp. 996-999 ◽  
Author(s):  
Bao Feng Zhang ◽  
Qi Chen ◽  
Xiao Wei Chen ◽  
Hong Liang Zhao
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Optical Microscopy ◽  
Energy Dispersive Spectrometer ◽  
Energy Dispersive ◽  
Chinese Script ◽  
Mg2si Phase ◽  
Small Block ◽  
Average Size ◽  
Scanning Electron

In this study, the effect of KBF4 addition on the microstructure of the Mg-6Zn-1Si alloy has been investigated by Optical Microscopy (OM), Scanning Electron Microscopy (SEM) with Energy Dispersive Spectrometer(EDS). At 1.5wt% KBF4 addition, the morphology of Mg2Si phase completely changed from Chinese script type into uniformly, dispersedly distributed graininess or small block, with the average size of the Mg-6Zn-1Si alloy decreasing from 135μm to 82μm.

Electroplated Si3N4 Reinforced Metal Matrix Nanocomposites

2003 ◽  
Author(s):  
Xiaochun Li ◽  
Zhiwei Li
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Metal Matrix ◽  
Volume Fraction ◽  
Energy Dispersive Spectrometer ◽  
Copper Substrate ◽  
Metal Matrix Nanocomposites ◽  
Matrix Nanocomposites ◽  
Matrix Nanocomposite ◽  
Scanning Electron

Permalloy NiFe matrix nanocomposite layers were electroplated on a copper substrate. The volume fraction of nano-sized Si3N4 particles in NiFe matrix was controlled by the addition of various percentages of Si3N4 particles in the NiFe electrolyte. The nanocomposite layers were analyzed by a scanning electron microscopy (SEM). Microhardness test was performed. With nano-sized Si3N4 particles in the NiFe matrix, the microhardness of NiFe was improved. The samples were then annealed at 800 °C for about 20 hours. The microhardness declined more with more Si3N4 particles in the NiFe matrix. The analysis result from Energy Dispersive Spectrometer (EDS) in the SEM showed that the hardness declination could be caused by the segregation of Si3N4 in the NiFe matrix. Finally this paper presents nanocomposite micromolds fabricated by electroplating onto polymer molds that were fabricated by micro-stereolithgraphy.

Composition and Microstructure of a Natural Nano-Structure Mineral: Six-Ring Rock

2011 ◽  
Vol 295-297 ◽  
pp. 869-872
Author(s):  
Qing Shan Li ◽  
Xin Wang ◽  
Jun Liu ◽  
Guang Zhong Xing
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Energy Dispersive Spectrometer ◽  
The Body ◽  
X Ray Diffraction ◽  
Nano Structure ◽  
X Ray ◽  
Transmission Electron ◽  
Nano Size ◽  
Scanning Electron

Six-ring Rock is widely used as containers of water and additives to produce health care products. In this paper, the composition and microstructure of Six-ring Rock have been investigated by using scanning electron microscopy, energy dispersive spectrometer, transmission electron microscopy, x-ray diffraction and other technologies. Results show that Six-ring Rock is composed of CaMg(CO3)2, SiO2 and KAlSi3O8. Fe atoms exist in CaMg(CO3)2 by replacing Mg atoms. Six-ring Rock shows nano-size lamellar and acerose microstructures on the surface, and nano-size monocrystals in the body. Six-ring Rock is a natural nano structure mineral.

Non-Metallic Inclusions in Mg-RE-Zr Casting Alloys

2014 ◽  
Vol 782 ◽  
pp. 398-403
Author(s):  
Bartłomiej Dybowski ◽  
Andrzej Kiełbus
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Liquid Metal ◽  
Magnesium Alloys ◽  
Gating System ◽  
Mould Material ◽  
Casting Alloys ◽  
Metallic Inclusions ◽  
Liquid Metal Surface ◽  
Scanning Electron

Non-metallic inclusions in Elektron 21 and WE43 magnesium alloys have been investigated by means of scanning electron microscopy. Investigations were conducted both on the fracture surfaces and microsections. Researches revealed presence of alloying elements oxides, inclusions originating in mould material and inclusions originating in the fluxes covering liquid metal surface in the cruicible. The number of inclusions is reduced by application of complex gating system and by leaving small amount of alloy in the cruicible after the pouring process.

The Corrosion of HDG Zinc Coatings on the Road and Urban Infrastructures

2015 ◽  
Vol 227 ◽  
pp. 217-220
Author(s):  
Agnieszka Królikowska ◽  
Leszek Komorowski
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Corrosion Resistance ◽  
Gravimetric Method ◽  
Optical Emission ◽  
Emission Spectrometry ◽  
The Road ◽  
On The Road ◽  
Zinc Coatings ◽  
Scanning Electron

The standard ISO 14713-1 shows that HDG coatings should protect steel in the corrosive atmosphere C5 for 10–21 years. It was observed that pitting corrosion appears already after 2–3 years on roads and urban infrastructures and both Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) have shown that lead inclusions were present in all such corroded zinc coatings. The laboratory prepared HDG coatings with different amount of lead inclusions were investigated by gravimetric method (after exposure in salt chamber), SEM with EDS, and Glow Discharge Optical Emission Spectrometry (GDOES). The corrosion resistance was analyzed in the polarization tests and local probe techniques. The inclusions could accelerate coating corrosion because lead is cathodic to zinc.

Study on the Electrical Arc Ablation Performance of Al2O3 Reinforced Cu-Matrix Composites

2012 ◽  
Vol 557-559 ◽  
pp. 267-271
Author(s):  
Bin Li ◽  
Gui Min Liu ◽  
Jian Hua Du ◽  
Xiao Hui Zheng ◽  
Qing Song Yong
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Copper Alloy ◽  
Energy Dispersive Spectrometer ◽  
Molten Copper ◽  
Matrix Composites ◽  
Electrical Arc ◽  
Anchoring Effect ◽  
Oxidation Technology ◽  
Scanning Electron

The Al2O3 particle reinforced Cu-based composites (Al2O3/Cu) were prepared by internal oxidation technology. The electrical arc ablation performance of Al2O3/Cu composite was compared with copper H62 through a series of ablation experiments. The results indicate that both the quality lost and ablation diameter of copper H62 samples are larger than those of Al2O3/Cu composites in condition of the same ablating current. The large ablation pits observed by scanning electron microscopy (SEM) indicated that the arc ablation of copper H62 is concentrate and serious. The result of energy dispersive spectrometer (EDS) shows that the molten copper alloy of H62 has been transferred and sprayed. However, the arc ablation pits of Al2O3/Cu composites are dispersing and slight. The transferring and spaying material of Al2O3/Cu composite is mainly from Cu-matrix. The anchoring effect and protection function of the uniformly dispersing Al2O3 grains, which are executed onto the Cu-matrix, has been considered to contribute to the excellent arc ablation performance of composite Al2O3/Cu.

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