scholarly journals Development of Co-Based Amorphous Composite Coatings Synthesized by Laser Cladding for Neutron Shielding

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 279
Author(s):  
Xiaobin Liu ◽  
Jiazi Bi ◽  
Ziyang Meng ◽  
Yubin Ke ◽  
Ran Li ◽  
...  
Keyword(s):  
Substrate Temperature ◽  
Laser Cladding ◽  
Metallic Glasses ◽  
Composite Coatings ◽  
Dilution Effect ◽  
Amorphous Coating ◽  
Neutron Shielding ◽  
Wide Range ◽  
High Microhardness ◽  
Amorphous Coatings

Advanced amorphous coatings consisting of Co-based metallic glasses with ultrahigh strength (6 GPa) and high microhardness (up to 17 GPa) can significantly improve the surface properties of matrix materials. However, the intrinsic brittleness of Co-based metallic glasses can lead to the initiation of microcracks caused by the inevitable generation of thermal stress during the laser cladding process, which severely limits the potential application. In this paper, the methods of increasing substrate temperature and fabricating composite coatings with the addition of toughened Fe powders were adopted to inhibit the generation of microcracks in the Co55Ta10B35 amorphous coatings. Moreover, neutron shielding performances of the cladding coatings with high B content were investigated with a wide range of neutron energy (wavelength: 0.15–0.85 nm). The results indicate that the fully amorphous coating and composite ones can be fabricated successfully. The increase in the substrate temperature and the addition of Fe powders can effectively inhibit the initiation and propagation of microcracks. The fully Co-based amorphous coating with high B content (35 at.%) can exhibit excellent neutron shielding performance. With the addition of Fe powders, the neutron shielding performance is reduced gradually due to the dilution effect of B in the composite cladding coatings, but the microcrack will be completely restrained.

Effect of Thermal Spray Processing Techniques on the Microstructure and Properties of Ni-Based Amorphous Coatings

2005 ◽  
Vol 475-479 ◽  
pp. 2887-2890
Author(s):  
Sang Mok Lee ◽  
B.M. Moon ◽  
Eric Fleury ◽  
H.S. Ahn ◽  
Do Hyang Kim ◽  
...  
Keyword(s):  
Plasma Spraying ◽  
Laser Cladding ◽  
Amorphous Materials ◽  
Limiting Factor ◽  
Amorphous Coating ◽  
Wear Properties ◽  
Vacuum Plasma Spraying ◽  
Coating Microstructure ◽  
Processing Techniques ◽  
Amorphous Coatings

Metallic amorphous materials have been widely developed thanks to the outstanding properties including high chemical stability, mechanical strength, and magnetic properties. However, with the exception of a few compositions, the limiting factor is the critical cooling rate for the formation of the amorphous phase. For many applications, it is only the contact surface properties that are important, thus the use of coating techniques such as thermal sprayings has several attractive features. In this paper, we present the microstructure of Ni-based amorphous coatings prepared by laser cladding and vacuum plasma spraying. The utilization of plasma spraying to deposit atomized powder enabled the formation of fully amorphous coating, laser cladding resulted in mostly crystallized structures. Glass forming ability and wear properties of the coatings were discussed as a function of the coating microstructure.

Laser cladding Ni-base composite coatings reinforced by in-situ synthesized multiple carbide particles

2008 ◽  
Author(s):  
Ruiquan Kang ◽  
Mingxing Ma ◽  
Wenjin Liu ◽  
Minlin Zhong ◽  
Yide Kan ◽  
...  
Keyword(s):  
Laser Cladding ◽  
Composite Coatings ◽  
Base Composite ◽  
Carbide Particles

scholarly journals Current Research Status on Cold Sprayed Amorphous Alloy Coatings: A Review

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 206
Author(s):  
Qiang Wang ◽  
Peng Han ◽  
Shuo Yin ◽  
Wen-Juan Niu ◽  
Le Zhai ◽  
...  
Keyword(s):  
High Temperature ◽  
Amorphous Alloy ◽  
Amorphous Alloys ◽  
Composite Coatings ◽  
Thermal Spraying ◽  
Functional Coatings ◽  
Research Status ◽  
Key Issues ◽  
Wear And Corrosion Resistance ◽  
Amorphous Coatings

Compared with traditional crystalline materials, amorphous alloys have excellent corrosion and wear resistance and high elastic modulus, due to their unique short-range ordered and long-range disordered atomic arrangement as well as absence of defects, such as grain boundaries and dislocations. Owing to the limitation of the bulk size of amorphous alloys as structural materials, the application as functional coatings can widely extend their use in various engineering fields. This review first briefly introduces the problems involved during high temperature preparation processes of amorphous coatings, including laser cladding and thermal spraying. Cold spray (CS) is characterized by a low-temperature solid-state deposition, and thus the oxidation and crystallization related with a high temperature environment can be avoided during the formation of coatings. Therefore, CS has unique advantages in the preparation of fully amorphous alloy coatings. The research status of Fe-, Al-, Ni-, and Zr-based amorphous alloy coatings and amorphous composite coatings are reviewed. The influence of CS process parameters, and powders and substrate conditions on the microstructure, hardness, as well as wear and corrosion resistance of amorphous coatings is analyzed. Meanwhile, the deposition mechanism of amorphous alloy coatings is discussed by simulation and experiment. Finally, the key issues involved in the preparation of amorphous alloy coatings via CS technology are summarized, and the future development is also being prospected.

scholarly journals Isothermal Oxidation Performance of Laser Cladding Assisted with Preheat (LCAP) Tribaloy T-800 Composite Coatings Deposited on EN8

Coatings ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 843
Author(s):  
Sipiwe Trinity Nyadongo ◽  
Sisa Lesley Pityana ◽  
Eyitayo Olatunde Olakanmi
Keyword(s):  
Iron Oxide ◽  
Composite Coating ◽  
Laser Cladding ◽  
Composite Coatings ◽  
Parabolic Rate Constant ◽  
Mass Gain ◽  
Isothermal Oxidation ◽  
Operational Parameters ◽  
Temperature Oxidation ◽  
Service Environments

It is anticipated that laser cladding assisted with preheat (LCAP)-deposited Tribaloy (T-800) composite coatings enhances resistance to structural degradation upon exposure to elevated-temperature oxidation service environments. The oxidation kinetics of LCAP T-800 composite coatings deposited on EN8 substrate and its mechanisms have not been explored in severe conditions that are similar to operational parameters. The isothermal oxidation behaviour of the T-800 composite coating deposited on EN8 via LCAP was studied at 800 °C in air for up to 120 h (5 × 24 h cycles) and contrasted to that of uncoated samples. The mass gain per unit area of the coating was eight times less than that of the uncoated EN8 substrate. The parabolic rate constant (Kp) for EN8 was 6.72 × 10−12 g2·cm−4·s−1, whilst that for the T-800 composite coating was 8.1 × 10−13 g2·cm−4·s−1. This was attributed to a stable chromium oxide (Cr2O3) layer that formed on the coating surface, thereby preventing further oxidation, whilst the iron oxide film that formed on the EN8 substrate allowed the permeation of the oxygen ions into the oxide. The iron oxide (Fe2O3) film that developed on EN8 spalled, as evidenced by the cracking of oxide when the oxidation time was greater than 72 h, whilst the Cr2O3 film maintained its integrity up to 120 h. A parabolic law was observed by the T-800 composite coating, whilst a paralinear law was reported for EN8 at 800 °C up to 120 h. This coating can be used in turbine parts where temperatures are <800 °C.

Phase transformation and tribological properties of Ag-MoO 3 contained NiCrAlY based composite coatings fabricated by laser cladding

2017 ◽  
Vol 93 ◽  
pp. 79-86 ◽  
Author(s):  
Lingqian Wang ◽  
Jiansong Zhou ◽  
Benbin Xin ◽  
Youjun Yu ◽  
Shufang Ren ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Laser Cladding ◽  
Tribological Properties ◽  
Composite Coatings

Ni Content Surface Layer Produced by Laser Surface Treatment on Amorphisable Cu Base Alloy

2010 ◽  
Vol 649 ◽  
pp. 101-106
Author(s):  
Mária Svéda ◽  
Dóra Janovszky ◽  
Kinga Tomolya ◽  
Jenő Sólyom ◽  
Zoltán Kálazi ◽  
...  
Keyword(s):  
Surface Layer ◽  
Surface Treatment ◽  
Laser Cladding ◽  
Base Alloy ◽  
Laser Surface ◽  
Laser Alloying ◽  
Laser Surface Treatment ◽  
Ni Content ◽  
Wide Range ◽  
The Matrix

The aim of our research was to comparatively examine Ni content surface layers on amorphisable Cu base alloy produced by different laser surface treatments. Laser surface treatment (LST) techniques, such as laser surface melting, laser alloying and laser cladding, provide a wide range of interesting solutions for the production of wear and corrosion resistant surfaces. [1,2] With LST techniques, the surface can be: i) coated with a layer of another material by laser cladding, ii) the composition of the matrix can be modified by laser alloying. [3] Two kinds of laser surface treatment technologies were used. In the case of coating-melting technology a Ni content surface layer was first developed by galvanization, and then the Ni content layer was melted together with the matrix. In the case of powder blowing technology Ni3Al powder was blown into the layer melted by laser beam and Argon gas. LST was performed using an impulse mode Nd:YAG laser. The laser power and the interaction time were 2 kW and 20÷60 ms. The characterization of the surface layer microstructure was performed by XRD, scanning electron microscopy and microhardness measurements.

scholarly journals Microstructures and Properties of Laser Cladding Al-TiC-CeO2 Composite Coatings

Materials ◽  
2018 ◽  
Vol 11 (2) ◽  
pp. 198 ◽  
Author(s):  
Xing He ◽  
Dejun Kong ◽  
Renguo Song
Keyword(s):  
Laser Cladding ◽  
Composite Coatings
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