Characterization of the Intermetallic Compounds Formed during Hot Dipping of Electrical Steel in a Hypo-Eutectic Al-Si Bath

2010 ◽  
Vol 297-301 ◽  
pp. 370-375 ◽  
Author(s):  
I. Infante Danzo ◽  
Kim Verbeken ◽  
Yvan Houbaert

In order to improve the magnetic properties of electrical steels, it may be desirable to increase the Si and/or Al content of the steel. A possible and alternative route to realize this is through the application of an Al-Si-rich coating on the steel substrate using a hot dipping process, followed by a diffusion annealing treatment. Previously, a series of compositions were used for dipping, namely: pure Al, Al + 10wt% Si (hypo-eutectic composition) and Al + 25wt% Si (hypereutectic composition). After these dipping experiments, and the subsequent evaluation of the coating and its formed intermetallic phases, the use of a hypo-eutectic Al-Si-bath was recommended for further investigation, because of certain advantages: i.e. hypo-eutectic concentrations allow lower dipping temperatures and reduce the formation of ordered Fe-Si-structures that cause brittleness in the coating and substrate. The present work reports on the results obtained on materials that were hot dipped in a hypo-eutectic Al-Si bath. An Al + 1wt%Si bath was used to coat electrical steel substrates with different silicon contents with dipping times, varying between 0 to 20 seconds, after a preheating of the samples to a temperature of 700°C. A thorough characterization of the formed intermetallics was made by Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS) and X-Ray Diffraction (XRD). Three different compounds were identified as Fe2Al5, FeAl3 and a nearly pure Al phase.

2012 ◽  
Vol 326-328 ◽  
pp. 428-433
Author(s):  
I. Infante Danzo ◽  
Benny Malengier ◽  
S. Miyar ◽  
E. Gomez ◽  
Kim Verbeken ◽  
...  

Hot dipping is a coating technique used in industry for galvanizing machine elements and steel profiles for construction or automotive applications. However, an alternative use of this process might be to improve specific properties. For instance, in order to improve the magnetic properties of electrical steels, it may be desirable to increase the Si and/or Al content. A possible and alternative route to realize this is by the application of an Al-Si-rich coating on the steel substrate using a hot dipping process, followed by a diffusion annealing treatment in order to distribute the Al/Si more evenly in the steel. The obtained distribution depends on the annealing parameters and can be both beneficial and detrimental for the magnetic properties. In the present work, Fe-Si substrates were hot dipped in different Al-Si baths. Subsequently, the samples were annealed at 1100°C during 20 minutes and concentration profiles were measured with scanning electron microscope energy dispersive spectroscopy line scans. The experimental results were analyzed using a specifically designed simulation model in order to determine the Al and Si diffusion coefficients. This model uses an inverse algorithm to determine interdiffusion coefficients that arise in a macro ternary diffusion system.


Author(s):  
Liliana-Laura Badita ◽  
Gheorghe Gheorghe ◽  
Vasile Bratu ◽  
Valentin Gornoava ◽  
Marian Vocurek ◽  
...  

Abstract Taking into account the importance of mechatronic applications, researches regarding the possibility to improve the lifetime of mechatronic components were made. Nanostructured metallic thin films (Ti, Cr, Al and Ti/Al multilayer) were deposited on different types of steel substrates, because nanomaterials have exceptional properties in relation to the common materials. In this paper a part of the results obtained after mechanical and topographic characterization of the thin films are presented. Cr is the deposited thin film showing the highest hardness on the surface of steel substrate type OSC. After the scratch tests realized, Ti layer presented the best adhesion on all types of steel substrates used in experiments. The results of these researches could be extremely useful for engineers in the mechatronic field.


2014 ◽  
Vol 487 ◽  
pp. 67-70
Author(s):  
Chien Cheng Liu ◽  
Kuang I Liu ◽  
Hao Tung Lin ◽  
Yung Chih Chou ◽  
Yung Mao Cheng ◽  
...  

ZrN thin films were successfully deposited by DC magnetron sputtering on die steel substrates. The objective of this study was to investigate heat treatment on the microstructure, morphology, nanohardness properties determined by X-ray diffraction, field-emission scanning electron microscope (FE-SEM), nanoindentation, and pin-on-disk, respectively. The XRD result shows that ZrN has intensity of (111) and (200) peak after 400 °C for 1 h at lower nitrogen flow rates. The surface of coatings revealed smaller grains and smooth surface under heat treatment. ZrN coatings consisted of lower nitrogen flow rate had much lower friction coefficient, better mechanical properties by annealing treatment process.


2021 ◽  
Vol 11 (3) ◽  
pp. 264
Author(s):  
Sghir Cherrouf ◽  
Yassine Salhi ◽  
Amina El Echhab ◽  
Hassan El Grini ◽  
Jihane Tellal ◽  
...  

<p>The tin coating was elaborated electrolytically on an ordinary steel substrate in SnSO<sub>4</sub> based electrolyte in acid medium with additive (bis-glycobenzimidazolone) at ambient temperature. The pH is maintained at 1.2±0.2 Bis-glycobenzimidazolone influence on the electrochemical properties of the tin coating was investigated using stationary polarization, chronopotentiometry, and cyclic voltammetry techniques. These studies show an apparent decrease in cathodic peak current and a drop in potential. The deposition rate also decreases as the concentration of the additive increases.  SEM (Scanning Electron Microscopy) observation and XRD (X-ray Diffraction) analysis showed that the coating consists of good surface quality of the deposit elaborated by the addition of an optimal concentration of bis-glycobenzimidazolone (10<sup>-3</sup>M) in the electrolyte, which constitutes the continuation of a preliminary study.<strong></strong></p>


2010 ◽  
Vol 17 (03) ◽  
pp. 375-381 ◽  
Author(s):  
ZHIJIA YU ◽  
YUEFEI YU ◽  
YANFENG LI ◽  
SHANPENG SONG ◽  
SUBIN HUO ◽  
...  

Hierarchical alveolate structures in nano- to microscale were fabricated on both aluminum and stainless steel substrates via a chemical etching. On aluminum surfaces, sharp edged caves and plateaus were found. On stainless steel substrate, fine papillae stand on protuberances. These surfaces exhibit super-hydrophobic properties after the fluorination treatment, their water contact angles are 158° and 160°, respectively, with the contact angle hysteresis of about 5°. The roll off angle is about 5°. Ice melting behaviors on a plate of aluminum super-hydrophobic surface were compared with those on a hydrophilic one, their difference shows that the new feature of super-hydrophobic surface could be expected.


2007 ◽  
Vol 539-543 ◽  
pp. 3341-3346
Author(s):  
Yvan Houbaert ◽  
Tanya Ros-Yáñez ◽  
Pablo Rodriguez-Calvillo ◽  
José Barros ◽  
Leo Kestens

Crystallographic texture has an important effect on the magnetic quality of electrical steel: a specific texture parameter A is defined and used to estimate the magnetic quality of texture components. It is shown that obtaining the best possible texture in non oriented electrical steel can reduce the losses with 1,5 W/kg. Two production schemes for high silicon electrical steel are described: a conventional processing through hot and cold rolling with adequate temperatures and cooling rates and an immersion-diffusion process by hot dipping in a Si- and Al-rich bath followed by diffusion annealing. The texture evolution in these experimental materials is under study and first results are reported for conventional alloys (rolling procedure) and for immersion-diffusion alloys, which are annealed after dipping in order to obtain a controlled concentration gradient with high Si and/or Al at the surface or a homogeneous Si and/or Al-content over the thickness.


2010 ◽  
Vol 168-170 ◽  
pp. 2430-2433 ◽  
Author(s):  
Zhi Hai Cai ◽  
Zhang Ping ◽  
Yue Lan Di

Approximately 2 μm thick CrN and CrAlN coatings were synthesized on silicon and spring steel substrate by multi-arc ion plating technology. The nanoindentation techniques, Auger electron spectroscopy (AES) analysis, scanning electron microscopy, X-ray diffraction and oxidation furnace were used to investigate the mechanical property, oxidation resistance and microstructure of the coatings. The XRD data showed that the CrN and CrAlN coatings exhibited B1 NaCl structure. Nanoindentation measurements showed that as-deposited CrN and CrAlN coatings exhibited a hardness of 19 and 30 GPa respectively. Compared with CrN coatings, the CrAlN composite coatings show much better oxidation resistance. And the oxidation resistance ability will enhance with increasing Al content, because A12O3 will form after oxidation in high temperature condition which could reduce the diffusivity ability of oxygen.


2011 ◽  
Vol 130-134 ◽  
pp. 994-997
Author(s):  
Jin Dong Wang ◽  
Fa Feng Xia

Nanocomposite Ni-Al2O3 thin film containing nanosized Al2O3 particles had been grown on steel substrate by ultrasonic-electrodeposited technology. The optimum technological parameters of nanocomposite Ni-Al2O3 thin films were obtained by experiments and analysis. X-ray diffraction analysis was utilized to detect the crystalline and amorphous characteristics of Ni-Al2O3 thin films. The surface morphology and metallurgical structure were analysed by high resolution transmission electron microscope, and scanning electron microscope. The test results showed that nanocomposite Ni-Al2O3 thin films prepared by proper ultrasonic-electrodeposited method consist of nanometer-sized Al2O3 particles and nickel grains. And the Al2O3 nanoparticles and Ni grains diameters in thin films are about 40nm and 80nm, respectively.


2011 ◽  
Vol 399-401 ◽  
pp. 760-765 ◽  
Author(s):  
Xue Ting He ◽  
Jie Tao ◽  
Hai Jun Tao ◽  
Zuo Guo Bao

Ti film sputtered on flexible stainless steel substrate that rolled by 20-high Sendzimir Mill, was anodized in ethylene glycol bath in the presence of 0.5 wt.% NH4F and 3 vol.% H2O at a high voltage of 60 V. High-aspect-ratio porous-nanotube arrays (PNTAs) of TiO2 with the tubes length of 6.2 µm were quickly prepared from Ti film, at the high growth rate of 20.7 nm·s-1. Then the morphology and structure of PNTAs were characterized by field emission scanning electron microscope (FESEM) and X-ray diffraction (XRD), respectively. Finally, a DSSC with the photoanode of PNTAs exhibited a performance of Jsc= 2.40 mA·cm-2, Voc= 0.79V, FF = 0.57 and η = 1.08%.


2008 ◽  
Vol 273-276 ◽  
pp. 63-68
Author(s):  
Pablo Rodriguez-Calvillo ◽  
P. Bernárdez ◽  
Yvan Houbaert

The addition of aluminium (and of silicon) to steel increases its electrical resistivity and reduces therefore the power losses in electrical devices. There is also a favourable effect on magnetostriction. Nevertheless, these additions make the steel extremely brittle and very difficult to process through a conventional thermomechanical route. The authors developed an innovative processing route, avoiding the rolling of a brittle steel sheet. The used process consists of the hot dipping of a steel substrate in a pure aluminium bath, followed by a diffusion annealing treatment. In order to study the reaction of the aluminium with the substrates and the diffusion process during further annealing, two substrates (ultra low carbon steel (ULC) and a Fe + 3.4 m.-% Si steel) were used for immersion in a pure aluminium bath. Dipping times and temperatures were varied in the range of 700 to 750 °C and 5 to 1000 sec., respectively. The different surface layers formed during dipping and after annealing were characterised with an Elcometer, by Scanning Electron Microscopy (SEM) and by Energy Dispersive Spectroscopy (EDS). The results show that the chemical composition of the layers obtained is strongly dependant on the initial substrate composition. Diffusion gradients of Al and Si in the steel after hot dipping and diffusion annealing are shown and discussed. Samples with a concentration gradient of Si and Al over the thickness have been produced. There is only a light reduction of the power losses for the substrate with 3.4 m.-% Si. The ultra low carbon substrate presents worse power losses after the processing. Further improvement of the processing is still required.


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