Effects of aluminum concentration on the formation of inhibition layer during hot-dip galvanizing

Author(s):  
Ting Min ◽  
Yimin Gao ◽  
Xiaoyu Huang ◽  
Zhanpeng Gong ◽  
Kemin Li ◽  
...  
2018 ◽  
Author(s):  
Peter George Gordon ◽  
Goran Bacic ◽  
Gregory P. Lopinski ◽  
Sean Thomas Barry

Al-doped ZnO (AZO) is a promising earth-abundant alternative to Sn-doped In<sub>2</sub>O<sub>3</sub> (ITO) as an n-type transparent conductor for electronic and photovoltaic devices; AZO is also more straightforward to deposit by atomic layer deposition (ALD). The workfunction of this material is particularly important for the design of optoelectronic devices. We have deposited AZO films with resistivities as low as 1.1 x 10<sup>-3</sup> Ωcm by ALD using the industry-standard precursors trimethylaluminum (TMA), diethylzinc (DEZ), and water at 200<sup>◦</sup>C. These films were transparent and their elemental compositions showed reasonable agreement with the pulse program ratios. The workfunction of these films was measured using a scanning Kelvin Probe (sKP) to investigate the role of aluminum concentration. In addition, the workfunction of AZO films prepared by two different ALD recipes were compared: a “surface” recipe wherein the TMA was pulsed at the top of each repeating AZO stack, and a interlamellar recipe where the TMA pulse was introduced halfway through the stack. As aluminum doping increases, the surface recipe produces films with a consistently higher workfunction as compared to the interlamellar recipe. The resistivity of the surface recipe films show a minimum at a 1:16 Al:Zn atomic ratio and using an interlamellar recipe, minimum resistivity was seen at 1:19. The film thicknesses were characterized by ellipsometry, chemical composition by EDX, and resistivity by four-point probe.<br>


2014 ◽  
Vol 887-888 ◽  
pp. 233-239 ◽  
Author(s):  
She Ming Jiang ◽  
Shi Jie Feng ◽  
Zhen Hua Li ◽  
Qi Fu Zhang

Focusing on improving the galvanizability of the third generation automotive steel, the effect of surface oxides morphologies on the galvanizability was studied. The results show that the surface oxide types of sample steels by XPS analysis after annealing in different conditions are the same, only MnO and Cr2O3 were detected and no complex oxides exist on the surface. Morphologies of surface oxides can greatly influence the galvanizability of the third generation automotive steel, nodule-like oxides surface can contribute to better wettability and inhibition layer than vitreous film-like oxides surface. Galvanizing panels of nodule-like oxides surface steels only show pinhole-sized bare spots, while panels galvanized from vitreous film-like oxide surface steels reveal larger areas of bare spots and uncoated areas. Inhibition layer observed in galvanizing panels of nodule-like oxides surface steels are compact but not homogeneous, some inhibition layer grains are fine, and others are coarse. While the inhibition layer grains of panels galvanized from vitreous film-like oxide surface steels have a non-compact morphology with some particularly fine equiaxed crystals which developed deficiently.


2019 ◽  
Vol 25 (1) ◽  
pp. 117-125 ◽  
Author(s):  
Wenxiong Lin ◽  
Huagang Liu ◽  
Haizhou Huang ◽  
Jianhong Huang ◽  
Kaiming Ruan ◽  
...  

PurposeThe purpose of this paper is to explore the possibility of an enhanced continuous liquid interface production (CLIP) with a porous track-etched membrane as the oxygen-permeable window, which is prepared by irradiating polyethylene terephthalate membranes with accelerated heavy ions. Design/methodology/approachExperimental approaches are carried out to characterize printing parameters of resins with different photo-initiator concentrations by a photo-polymerization matrix, to experimentally observe and theoretically fit the oxygen inhibition layer thickness during printing under conditions of pure oxygen and air, respectively, and to demonstrate the enhanced CLIP processes by using pure oxygen and air, respectively. FindingsOwing to the high permeability of track-etched membrane, CLIP process is demonstrated with printing speed up to 800 mm/h in the condition of pure oxygen, which matches well with the theoretically predicted maximum printing speed at difference light expose. Making a trade-off between printing speed and surface quality, maximum printing speed of 470 mm/h is also obtained even using air. As the oxygen inhibition layer created by air is thinner than that by pure oxygen, maximum speed cannot be simply increased by intensifying the light exposure as the case with pure oxygen. Originality/valueCLIP process is capable of building objects continuously instead of the traditional layer-by-layer manner, which enables tens of times improvement in printing speed. This work presents an enhanced CLIP process by first using a porous track-etched membrane to serve as the oxygen permeable window, in which a record printing speed up to 800 mm/h using pure oxygen is demonstrated. Owing to the high permeability of track-etched membrane, continuous process at a speed of 470 mm/h is also achieved even using air instead of pure oxygen, which is of significance for a compact robust high-speed 3D printer.


Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 3147 ◽  
Author(s):  
Wu Xu ◽  
Yong Jiang

The effect of NaCl as an extinguishing agent on metal dust fires require further exploration. This paper reports the results of an experimental study on the performance of micron-sized NaCl powders on hybrid aluminum–methane–air flames. NaCl particles with sub-10 μm sizes were newly fabricated via a simple solution/anti-solvent method. The combustion characteristics of aluminum combustion in a methane-air flame were investigated prior to the particle inhibition study to verify the critical aluminum concentration that enables conical aluminum-powder flame formation. To study the inhibition effectiveness, the laminar burning velocity was measured for the established aluminum–methane–air flames with the added NaCl using a modified nozzle burner over a range of dust concentrations. The results were also compared to flames with quartz sand and SiC particles. It is shown that the inhibition performance of NaCl considerably outperformed the sand and SiC particles by more rapidly decreasing the burning velocity. The improved performance can be attributed to contributions from both dilution and thermal effects. In addition, the dynamic behavior of the NaCl particles in the laminar aluminum–methane–air flame was investigated based on experimental observations. The experimental data provided quantified the capabilities of NaCl for metal fire suppression on a fundamental level.


1977 ◽  
Vol 57 (2) ◽  
pp. 239-244 ◽  
Author(s):  
C. B. BAILEY

Aluminum hydroxide was precipitated from aqueous solutions containing aluminum sulphate and silicic acid by adjusting the pH to within the range 6–7.5. The precipitated aluminum hydroxide formed an insoluble complex with the silicic acid and, in so doing, reduced the concentration of soluble silicic acid from 22 mg/dl to less than 5 mg/dl. Maximum reduction in silicic acid concentration occurred when the aluminum concentration was 30 mg/dl or more. The effects of adding rumen fluid to the solutions or of varying pH over the range 6–7.5 were small except at the lowest level of aluminum used (15 mg/dl). Aluminum sulphate, included in a prairie grass hay diet at 1.57%, reduced the concentration of silicic acid in the rumen fluid of cattle from 19.2 to 16.9 mg/dl. The same diet given to sheep had no significant effect on excretion of silicic acid in urine. A feeding trial with calves to assess the effects of the aluminum sulphate diet on calculus formation was not completed because the calves ate very little of the diet. The results confirmed earlier findings that aluminum hydroxide has a strong affinity for silicic acid. However, failure of the aluminum sulphate diet to lower rumen fluid concentration or urinary excretion of silicic acid to any great extent, and the low payability of the diet for calves, suggests that aluminum sulphate cannot be used to reduce absorption and excretion of silicic acid in calves on diets predisposing to the formation of siliceous calculi.


Polyhedron ◽  
1992 ◽  
Vol 11 (15) ◽  
pp. 1901-1907 ◽  
Author(s):  
C. Exley ◽  
J.D. Birchall

2020 ◽  
Vol 11 (1) ◽  
pp. 115
Author(s):  
Magnus Engholm ◽  
Matthew Tuggle ◽  
Courtney Kucera ◽  
Thomas Hawkins ◽  
Peter Dragic ◽  
...  

Author(s):  
Gang Chen ◽  
Peter Grasel ◽  
Gary Millington ◽  
John Hallas ◽  
Hafiz Ahmad ◽  
...  

Besides organic contaminants, nutrients and heavy metals, high concentrations of chloride have also been observed in landfills accepting ash deposition from waste-to-energy applications, which is difficult be removed in wastewater treatment processes. Chloride may percolate and cause surface salt formation and soil alkalinity increase, thereby resulting in loss of soil. In plants, chloride tends to accumulate in the tissues, especially the leaves. Conventional removal techniques are not feasible from the cost perspective. In this research, the ultra-high lime with aluminum process was evaluated for chloride removal from landfill leachate by precipitation as calcium chloroaluminate (Ca4Al2Cl2(OH)12) in the presence of calcium and aluminum at high pH. Chloride removal was found to be a function of both aluminum concentration and pH. Chloride removal increased with the increase of alum addition until 20 mg/L, after which the chloride removal became moderate. With the increase of pH, obviously more chloride was removed. At pH of 10, the removal reached 90%. To save the chemical costs, alum sludge from a drinking water treatment plant was tested for the removal of chloride from the landfill leachate. The results showed that the supernatant of the alum sludge was more efficient than that of alum sludge suspension in chloride removal. The usage of alum sludge can dramatically save the chemical costs.


1990 ◽  
Vol 213 ◽  
Author(s):  
C. T. Liu ◽  
E. P. George

ABSTRACTThe room-temperature tensile properties of FeAl aluminides were determined as functionsof aluminum concentration (35 to 43 at. % Al), test environment, and surface (oil) coating. The two lower aluminum alloys containing 35 and 36.5% Al are prone to severe environmental embrittlement, while the two higher aluminum alloys with 40 and 43% Al are much less sensitive to change in test environment and surface coating. The reason for the different behavior is that the grain boundaries are intrinsically weak in the higher aluminum alloys, and these weak boundaries dominate the low ductility and brittle fracture behavior of the 40 and 43% Al alloys. When boron is added to the 40% Al alloy as a grain-boundary strengthener, the environmental effect becomes prominent. In this case, the tensile ductility of the boron-doped alloy, just like that of the lower aluminum alloys, can be dramatically improved by control of test environment (e.g. dry oxygen vs air). Strong segregation of boron to the grain boundaries, with a segregation factor of 43, was revealed by Auger analyses.


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