Enhancement of Magnetic Properties of 41CrMo4 Steel by Means of Diffusion Coatings

The knowledge of magnetic and transport properties of construction steels for magnetic circuits plays an important role. Three different techniques: (i) flame spray, (ii) twin wire arc spray and (iii) powder mixture with halide activator were used to produce Si, CuSn6 and Si coatings, respectively, on the 41CrMo4 steel ring substrates. Immediately after the thermal spraying or inserting the steels into the powder mixture was used isothermal heat treatment at the temperatures of 800 °C / 6 hrs, 1000 °C / 4 hrs and 1250 °C / 2 hrs to produce the diffusion coatings. Several coating systems consisting of different phases and thicknesses were manufactured. Opto-digital microscope, scanning electron microscope and digital image analysis, second equipped with energy dispersive microanalyzer, were utilized to characterize the microstructure, chemical composition and thicknesses of the coatings. The influence of coatings on magnetic properties in the frequency range of 50-2000 Hz was also measured.

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Influence of mechanical activation and heat treatment on magnetic properties of nanostructured mixture Ni85.8Fe10.6Cu2.2W1.4

Journal of Mining and Metallurgy Section B Metallurgy ◽

10.2298/jmmb180809004v ◽

2019 ◽

Vol 55 (1) ◽

pp. 85-93 ◽

Cited By ~ 2

Author(s):

M.M. Vasic ◽

A.S. Kalezic-Glisovic ◽

R. Milincic ◽

Lj. Radovic ◽

D.M. Minic ◽

...

Keyword(s):

Magnetic Properties ◽

Thermal Treatment ◽

Mechanical Activation ◽

Powder Mixture ◽

Structural Characteristics ◽

Volume Density ◽

Magnetic Domains ◽

Microstructural Changes ◽

Mass Magnetization ◽

Stress Relieving

The mechanical activation of the Ni85.8Fe10.6Cu2.2W1.4 powder mixture in the time intervals of 30-210 min in combination with thermal treatment at 393-873 K resulted in microstructural changes, forming the nanostructured mixture of the same composition but improved magnetic properties. The best result were achieved for mechanical activation during 120 min and thermal treatment at temperatures close to the Curie temperature (693K), enhancing the mass magnetization of the starting powder mixture by about 57%. The microstructural changes, which include the structural relaxation, decrease in free volume, density of dislocation and microstrain, improve structural characteristics of material, enabling better mobility of walls of magnetic domains and their better orientation in applied magnetic field and consequently enabling better mass magnetization of the material. With longer time of milling, the growing stress introduced in the sample undergoes easier relief, relocating stress-relieving processes toward lower temperatures.

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Cored Wire Application Using Electric Arc Spray

Thermal Spray 1998: Proceedings from the International Thermal Spray Conference ◽

10.31399/asm.cp.itsc1998p0133 ◽

1998 ◽

Author(s):

E.R. Sampson

Keyword(s):

Trend Analysis ◽

Thermal Spraying ◽

Electric Arc ◽

Cored Wire ◽

Arc Spray ◽

New Development ◽

The Future ◽

Cored Wires

Abstract The use of cored wires for thermal spraying is a relatively new development that is being rapidly utilized for arc spray in a wide variety of applications. This paper will discuss the existing applications and industries in which cored wire coatings are used. Additionally, this presentation will cover the effect cored wires have had on the use ofother types ofthermal spray equipment. The paper will close with a trend analysis that discusses the applications of the future.

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Thermal Spray for Corrosion Control: A Competitive Edge for Commercial Shipbuilding

Journal of Ship Production ◽

10.5957/jsp.1995.11.1.53 ◽

1995 ◽

Vol 11 (01) ◽

pp. 53-55

Author(s):

Frank S. Rogers

Keyword(s):

Thermal Spray ◽

Marine Environment ◽

Thermal Spraying ◽

Spray Coating ◽

Cost Effective ◽

Thermal Spray Coating ◽

Coating System ◽

Protection Mechanism ◽

Arc Spray ◽

Spray System

Thermal spraying of steel with aluminum to protect it from corrosion is a technology that has been proven to work in the marine environment. The thermal spray coating system includes a paint sealer that is applied over the thermally sprayed aluminum; this extends the service life of the coating, and provides color to the end product. The thermal spray system protects steel both through the principle of isolation (as in painting) and galvanization (as in galvanizing). With this dual protection mechanism, steel is protected from corrosion even when the coating is damaged. The thermal sprayed aluminum coating system has proven to be the most cost-effective corrosion protection system for the marine environment. Until recently, however, the initial cost of application has limited its use for general application. Today a new arc spray technology has reduced the application cost of thermal spraying aluminum to below that of painting. Commercial shipbuilders could use this technology to enhance their market position in the marine industry.

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Novel Concept for Totally Integrated Automation (TIA) Using Siemens Bus System and WinCC Online Control

Thermal Spray 2000: Proceedings from the International Thermal Spray Conference ◽

10.31399/asm.cp.itsc2000p0963 ◽

2000 ◽

Author(s):

T. Frederking ◽

R. Gadow

Keyword(s):

Process Parameters ◽

High Speed ◽

Data Exchange ◽

Thermal Spraying ◽

Software Tool ◽

Functionally Graded ◽

Flame Spray ◽

Total Quality ◽

Spray Process ◽

Bus System

Abstract Total quality management requires definite process control as well as online diagnostics, if applied in industrial surface refinement by thermal spraying. A concept for integrated online diagnostics for the high velocity oxygen fuel (HVOF) flame spray process is presented using Siemens S7-300 programmable logic controller and PC-based Siemens WinCC (Windows Control Center) visualization software. The standard functionality of the WinCC programming environment can be extended by C-scripts. The integrated database allows to protocol the relevant process parameters periodically for total quality assurance. Also particle flux imaging software tools can be implemented to adjust online process parameters and for process diagnostic purposes. The Siemens bus system hierarchy thereby provides high speed communication skills for field bus level data exchange and for supervising system components, e.g. CCD-cameras. The interconnection between S7-300 PLC, 6-axis-robot and a novel WinCC software tool enables definite automatic changes of recipes during the coating process to generate functionally graded coatings.

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Structural and Magnetic Properties of Fe60–xNix(ZnO)40 Nanocomposites Produced by Mechanical Milling and Coated by Thermal Spraying on a Steel Substrate

Powder Metallurgy and Metal Ceramics ◽

10.1007/s11106-020-00136-7 ◽

2020 ◽

Vol 59 (1-2) ◽

pp. 35-45

Author(s):

Nacer Dilmi ◽

Nacer-Eddine Bacha ◽

Abderrahmane Younes

Keyword(s):

Magnetic Properties ◽

Mechanical Milling ◽

Steel Substrate ◽

Thermal Spraying ◽

Structural And Magnetic Properties

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High-Temperature Oxidation Resistance of NiAl Intermetallic Formed In Situ by Thermal Spraying

Coatings ◽

10.3390/coatings8080292 ◽

2018 ◽

Vol 8 (8) ◽

pp. 292 ◽

Cited By ~ 3

Author(s):

Qianqian Jia ◽

Deyuan Li ◽

Shumei Li ◽

Zhuang Zhang ◽

Nannan Zhang

Keyword(s):

Composite Coating ◽

Intermetallic Layer ◽

Thermal Spraying ◽

Diffusion Region ◽

Temperature Oxidation ◽

Arc Spray ◽

Different Temperatures ◽

Oxidation Resistant ◽

Oxidation Testing

An Al/Ni composite coating was deposited on the surface of a pure Ti substrate by arc spray technology and plasma spray technology. In order to enable the in-situ reaction between the Al/Ni composite coating and the specimen, they were heated under different conditions. In addition, oxidation testing was conducted to test the oxidation-resistant property of the coating. The phase transition regulation of the coating after heating, the influence of heating at different temperatures and time on the reaction depth, and the correlated theory of the in-situ formation of the NiAl intermetallic compounds were studied and analyzed. The results showed that after the heat treatment, a ragged wave-like morphology was exhibited in the diffusion front of Al, and a small amount of the Ni in the diffusion region did not participate in the reaction. The growth of the NiAl intermetallic layer in the diffusion region of the Al/Ni/Ti specimen was obviously slower compared with the Al/Ni specimen.

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Microstructural investigation of the coatings prepared by simultaneous aluminizing and siliconizing process on γ-TiAl

Journal of Mining and Metallurgy Section B Metallurgy ◽

10.2298/jmmb180814021n ◽

2019 ◽

Vol 55 (2) ◽

pp. 217-225

Author(s):

S. Nouri ◽

M. Azadeh

Keyword(s):

Powder Mixture ◽

Pack Cementation ◽

Chemical Compositions ◽

Powder Mixtures ◽

Microstructural Investigation ◽

Diffusion Coatings ◽

Sequential Mechanism ◽

First Time ◽

Pack Cementation Process ◽

Segregated Structure

In this research, formation of aluminide/silicide diffusion coatings on ?-TiAl[Ti-48Al-2Nb?2Cr (at.%)] alloy using gasphase diffusion pack cementation process has been investigated. The application of powder mixtures with various chemical compositions in the pack cementation process performed at 1000oC for 6 hours in order to achieve simultaneous diffusion of Al and Si, showed that the composition of the powder mixture could have a significant effect on the structure and thickness of the aluminide/silicide coatings. The identification and analysis of aluminide/silicide microstructures formed as a result of simultaneous diffusion of Al and Si, which was comprehensively and qualitatively done for the first time in this study, showed that the sequential mechanism is dominant in the formation of the above-mentioned coatings. Furthermore, Kirkendall phenomenon and volumetric changes caused by the formation of Ti5Si3 and Ti5Si4, were considered as the two dominant mechanisms in the formation of porous segregated structure in these coatings. In this study, the effect of decreasing the activity of Si, through two approaches of reducing the amount of Si in the powder mixture and using Al- 20wt.%Si alloyed powder instead of pure Al and Si depositing elements, on the microstructural modification coatings was investigated. The results showed that reducing the Si activity at the surface of the coating and, consequently, reducing the flux of active silicon atoms (JSi), has a significant effect on the formation of coating with an ideal structure.

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Correlations between In-Flight Particles, Splats and Coating Microstructures of Ni20Cr Thermally Sprayed by Flame and Arc Spray Processes

Materials Science Forum ◽

10.4028/www.scientific.net/msf.534-536.409 ◽

2007 ◽

Vol 534-536 ◽

pp. 409-412

Author(s):

Pisit Apichayakul ◽

Sittichai Wirojanupatump ◽

Sukanda Jiansirisomboon

Keyword(s):

Size Distribution ◽

Splat Morphology ◽

Flame Spray ◽

Spray Process ◽

Arc Spray ◽

Lower Porosity ◽

Coating Formation ◽

Coating Microstructure ◽

Higher Temperature ◽

Thermally Sprayed

Correlations between in-flight particle, splat and coating microstructure of thermally sprayed Ni20Cr were investigated. Flame spray and arc spray systems were employed for spraying Ni20Cr powder and Ni20Cr wire, respectively. The results showed that the arc spray process produced a broader size distribution for both in-flight particles and splats compared to flame process. Flower-like splat morphology was obtained from the arc spray whereas a pancake-like splat was obtained by flame spray. Ni20Cr coating sprayed by arc process had a denser microstructure, lower porosity and better adhesion at the interface. This could be due to the higher temperature and velocity from the arc spray process enhancing the melting and adhering for coating formation.

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Degradation Evaluation of HK40 Steel Using Magnetic Properties

International Journal of Modern Physics B ◽

10.1142/s0217979203019915 ◽

2003 ◽

Vol 17 (08n09) ◽

pp. 1940-1946

Author(s):

Seung Hoon Nahm ◽

Jong Seo Park ◽

Si Cheon Kim ◽

Kwon Sang Ryu ◽

Jeong Min Kim ◽

...

Keyword(s):

Magnetic Properties ◽

Magnetic Susceptibility ◽

Vickers Hardness ◽

Room Temperature ◽

High Reliability ◽

Tube Steel ◽

Isothermal Heat Treatment ◽

Isothermal Heat Treatments ◽

Heater Tube ◽

Degradation Evaluation

The effect of isothermal heat treatments, which simulate the microstructural changes observed in furnace heater tube steel at the service temperature, on the magnetic properties was investigated. HK40 steel specimens with five different periods of aging were prepared by an isothermal heat treatment at 1050°C. Magnetic properties such as susceptibility were measured. The magnetic susceptibility at room temperature monotonously increased with the extent of degradation of the material. The Vickers hardness also increased with the extent of degradation. The correlation between the measured magnetic susceptibility and the Vickers hardness was studied. In addition, the applicability of magnetic susceptibility measurements to the evaluation of degraded HK40 steel was discussed. As result, the magnetic susceptibility method could predict the thermal degradation of HK40 steel with high reliability.

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