Microstructure and Tribological Properties of Self-Lubricating Graphite/Ni60 Composite Coatings Prepared by Laser Cladding

2012 ◽  
Vol 583 ◽  
pp. 27-31 ◽  
Author(s):  
Jiao Xi Yang ◽  
Zhi Cheng Wang ◽  
Xuan He Miao ◽  
Xi Bing Wang
Keyword(s):  
Composite Coating ◽  
Laser Cladding ◽  
Steel Substrate ◽  
Composite Coatings ◽  
Solid Lubricants ◽  
Composition Analysis ◽  
Metallurgical Bonding ◽  
Lubricating Property ◽  
Increasing Temperature

Ni60 superhard alloy with the additions of graphite solid lubricants was successfully prepared on 45 carbon steel substrate by means of laser cladding. The quality of coating was relatively high and had metallurgical bonding with the substrate. The morphology of laser cladding layer was observed by SEM, composition analysis was applied by EDS. Elevated temperature frictional behaviors of graphite/Ni60 composites coatings were investigated on MMG-10 wear machine. The results showed that the friction coefficient of graphite/Ni60 composite coating was obviously decreased from 0.55 to 0.20 with increasing temperature. The wear mechanism transformed from adhesion to oxidation with the increase of temperature. The graphite/Ni60 composite coating material showed the optimum self-lubricating property at 500°C.

Characteristics of Laser Cladded Nickel-Based Chromic Carbide Composite Coatings

2017 ◽  
Vol 893 ◽  
pp. 340-344
Author(s):  
Sheng Dai ◽  
Dun Wen Zuo ◽  
Xian Rui Zhao ◽  
Jin Fang Wang
Keyword(s):  
Wear Resistance ◽  
Carbon Steel ◽  
Composite Coating ◽  
Steel Substrate ◽  
Composite Coatings ◽  
Surface Hardness ◽  
Micro Hardness ◽  
Wear Properties ◽  
Hardness Tester ◽  
Metallurgical Bonding

To improve the surface hardness and wear resistance of metal parts. Ni-based chromic carbidecomposite coating was prepared on the carbon steel (0.45 mass% C) substrates by laser cladding. Microstructure and wear properties of composite coatings were investigated by SEM, EDS, XRD, Vickers micro-hardness tester and wear machine. The results show that good metallurgical bonding between the Ni-based chromic carbidecomposite coating and carbon steel substrate. Micro-hardness of Ni-based Cr3C2 composite coating along the layer depth presents an evident stepladder distribution. The average micro-hardness of the laser clad coating is about 950 HV. The result of wear experiment shows that Ni-based Cr3C2 composite coating processes good wear resistance.

Bioceramic Composite Coatings Fabricated by Nd-YAG Laser Cladding Process on Ti6Al4V Substrate

2012 ◽  
Vol 198-199 ◽  
pp. 68-71 ◽  
Author(s):  
Ying Chun Wang ◽  
Yu Yong Yang ◽  
Mei Chun Wang
Keyword(s):  
Calcium Phosphate ◽  
Composite Coating ◽  
Laser Cladding ◽  
Composite Coatings ◽  
Mechanism Analysis ◽  
Yag Laser ◽  
Ti6al4v Substrate ◽  
Metallurgical Bonding ◽  
Laser Cladding Process ◽  
Modification Procedure

Laser cladding technology was adopted to fabricate hydroxyapatite(HAP) and calcium phosphate compound coating according to the feature that a metallurgical bonding can be formed by laser cladding process. Compared with CO2laser, Nd-YAG laser has different wavelength(the former is 1.06μm and the latter is 10.06μm). Metal and ceramic material has quite different absorbance ability towards them and thus they can generate different laser cladding products by these two laser surface processings with different wavelength. This paper presents a new process and mechanism analysis to obtain bioceramic composite coating on Ti6Al4V substrate by Nd-YAG laser cladding. A bioceramic composite coating including HAP，Ca2P2O7，Ca3(PO4)2and calcium titanates and was successfully obtained by Nd-YAG laser cladding with pre-depositing mixed powders of CaHPO4•2H2O and CaCO3directly on Ti6Al4V substrate. Nd-YAG laser transmits mixed powders of CaHPO4•2H2O and CaCO3and the laser power is absorbed by Ti6Al4V substrate to produce a thin layer of molten region. There are mainly two kinds of chemical reaction systems in the coating during laser cladding processing. When CaHPO4•2H2O and CaCO3react together, they make calcium phosphate bioceramic products; The microstructure of the bioceramic composite coating is even and minute because of the rapid solidification in laser processing. A chemical metallergical bonding is formed between the boceramic composite coating and Ti6Al4V substrate. It can also be expected that Nd-YAG laser cladding technology can be used as a further modification procedure to enhance HAp/metal interface property.

scholarly journals Microstructure and Wear Behavior of Laser Cladded Ni45 + High-Carbon Ferrochrome Composite Coatings

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1611
Author(s):  
Jiayang Gu ◽  
Ruifeng Li ◽  
Shungao Chen ◽  
Yuhao Zhang ◽  
Shujin Chen ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Composite Coating ◽  
Laser Cladding ◽  
Wear Behavior ◽  
Steel Substrate ◽  
Composite Coatings ◽  
Solid Solution Phase ◽  
High Carbon ◽  
Carbon Ferrochrome ◽  
1045 Steel

A composite coating with enhanced mechanical properties including high hardness and excellent wear resistance was produced by laser cladding of mixed Ni45 and high-carbon ferrochrome powders on an ASTM 1045 steel substrate. Different quantities, ranging from 10 to 50 wt.% of high-carbon ferrochrome powder were added to the Ni45 powder to investigate the effect of mixture content on the cladding performance. The microstructure of the coatings were examined using scanning electron microscope, and the wear resistance was compared using a wear tester apparatus among the different cases. The results showed that the microstructure of the coating with 30 wt.% high-carbon ferrochrome content was mainly fine solid solution phase. With the increase of high-carbon ferrochrome content to 40 wt.% and above, cracks appeared on the cladding surface due to a large amount of chromium carbides formed during the process. The microhardness was enhanced remarkably by laser cladding the composite coating on the 1045 substrate, with 2.4 times higher than the hardness of the substrate when 30 wt.% high-carbon ferrochrome content was added. The best wear performance was achieved when the high-carbon ferrochrome content was 30 wt.%, demonstrating the smallest surface roughness and depth of wear marks. With further increased high-carbon ferrochrome content, microcracking and delamination were observed on the worn surfaces.

Hardness Regulation of Fe-Based Amorphous Composite Coatings by Laser Remelting

2014 ◽  
Vol 789 ◽  
pp. 64-69 ◽  
Author(s):  
Yong Tian Wang ◽  
Ming Ming Yuan ◽  
Jing Kang Duan ◽  
Run Sen Jiang ◽  
Lin Hu ◽  
...  
Keyword(s):  
Composite Coating ◽  
Laser Power ◽  
Volume Fraction ◽  
Steel Substrate ◽  
Composite Coatings ◽  
Power Input ◽  
Arc Spraying ◽  
Laser Remelting ◽  
Application Fields

A Fe-based amorphous composite coating was deposited on a carbon steel substrate by arc spraying, and remelted with different laser energies by the Nd: YAG laser cladding system, in order to improve the mechanical properties of the coatings. The microstructure and microhardness of the composite coatings were investigated. The variation of harndness was measured as a function of the modified layer depth, which indicates that the laser remelting improves the bonding strength and hardness. Increasing the laser power, the quality of coating gets better, but the amorphous volume fraction decreases. It is obtained that the optimal laser electric current for the coating of 280 μm thickness is about 300 A, in which the remelted coating with medium energy densities has the highest average Vickers hardness of 741. Through the volume fraction change of the nanocrytals, the hardness of the composite coating is regulated by the laser power input, which amplified the application fields of the amorphous coatings.

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.

Study on the Wear Resistance of Micro-Nanostructured WC Composite Coating Sintered by Induced Heating

2007 ◽  
Vol 280-283 ◽  
pp. 1489-1492
Author(s):  
Zhen Ting Wang ◽  
Hua Hui Chen
Keyword(s):  
Wear Resistance ◽  
Composite Coating ◽  
Solid Solutions ◽  
Composite Coatings ◽  
Micro Hardness ◽  
Q235 Steel ◽  
Metallurgical Bonding ◽  
Sintering Method

Micro-nanostructured WC composite coatings were successfully fabricated by induced heating sintering method on the surface of Q235 steel .The microstructure, micro-hardness and the wear resistance of the composite coatings were studied .The results show that the microstructure of induced heat layer is mainly composed of Ni-based solid solutions and WC particles. And there exists excellent metallurgical bonding between coating and substrate. The wear resistance of micro-nanostructured WC Composite Coatings is increased by 1.5 times on an average as compared with that of micron.

scholarly journals Laser Cladding of Ni-Co-W Composite Coating on Stainless Steel to Enhance Wear Resistance

2021 ◽  
Author(s):  
Linlin ZHANG ◽  
Dawei ZHANG
Keyword(s):  
Stainless Steel ◽  
Wear Resistance ◽  
Composite Coating ◽  
Laser Cladding ◽  
Composite Coatings ◽  
Eutectic Structure ◽  
Wear Properties ◽  
Fine Grained ◽  
Noticeable Improvement ◽  
Enhance Wear Resistance

Ni-Co-W composite coatings modified by different contents of Co-based alloy powder in the Ni-based alloy with 35 wt.% WC (Ni35WC) were deposited on stainless steel by laser cladding. The influence of compositional and microstructural modification on the wear properties has been comparatively investigated by XRD, SEM, and EDS techniques. It was found that the austenite dendrites in the modified coating adding 50 wt.% Co-based alloy were refined and a lot of Cr23C6 or M23(C, B)6 compounds with fine lamellar feature were formed around austenitic grain boundaries or in the intergranular regions. The contribution of element Co to the modification of Ni35WC coating is that it cannot only promote the formation of more hard compounds to refine austenite grains, but also refine the size of precipitates, and change the phase type of eutectic structure as a result of disappeared Cr boride brittle phases. A noticeable improvement in wear resistance is obtained in the Ni35WC coating with 50 wt.% Co-based alloy, which makes the wear rate decreased by about 53 % and 30% by comparison to that of the substrate and the Ni35WC coating, respectively. It is suggested that the improvement is closely related to the composite coating being strengthened owing to the increase of coating hardness, formation of a fine-grained microstructure caused by Co, and fine hard precipitate phases in the eutectic structure.

scholarly journals Optimization of Ni-Based WC/Co/Cr Composite Coatings Produced by Multilayer Laser Cladding

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Andrea Angelastro ◽  
Sabina L. Campanelli ◽  
Giuseppe Casalino ◽  
Antonio D. Ludovico
Keyword(s):  
Laser Cladding ◽  
Steel Substrate ◽  
Composite Coatings ◽  
Metallic Matrix ◽  
Optimization Procedure ◽  
High Hardness ◽  
Fatigue Properties ◽  
Metal Composite ◽  
Tungsten Carbides ◽  
Cobalt Chromium

As a surface coating technique, laser cladding (LC) has been developed for improving wear, corrosion, and fatigue properties of mechanical components. The main advantage of this process is the capability of introducing hard particles such as SiC, TiC, and WC as reinforcements in the metallic matrix such as Ni-based alloy, Co-based alloy, and Fe-based alloy to form ceramic-metal composite coatings, which have very high hardness and good wear resistance. In this paper, Ni-based alloy (Colmonoy 227-F) and Tungsten Carbides/Cobalt/Chromium (WC/Co/Cr) composite coatings were fabricated by the multilayer laser cladding technique (MLC). An optimization procedure was implemented to obtain the combination of process parameters that minimizes the porosity and produces good adhesion to a stainless steel substrate. The optimization procedure was worked out with a mathematical model that was supported by an experimental analysis, which studied the shape of the clad track generated by melting coaxially fed powders with a laser. Microstructural and microhardness analysis completed the set of test performed on the coatings.

Wear Resistance of Laser Cladded NiCrFeSiB Self-Fluxing Composite Coatings

2016 ◽  
Vol 254 ◽  
pp. 290-295
Author(s):  
Iosif Hulka ◽  
Ion Dragoş Uţu ◽  
Viorel Aurel Şerban ◽  
Alexandru Pascu ◽  
Ionut Claudiu Roată
Keyword(s):  
Wear Resistance ◽  
Laser Cladding ◽  
Wear Behavior ◽  
Protective Coatings ◽  
Steel Substrate ◽  
Composite Coatings ◽  
Base Material ◽  
Laser Cladding Process ◽  
Metallurgical Bond ◽  
Feedstock Material

Laser cladding process is used to obtain protective coatings using as heat source a laser. This melts the substrate and the feedstock material to create a protective coating and provides a strong metallurgical bond with minimal dilution of the base material and reduced heat affected zone. In the present study a commercial NiCrSiFeB composition was deposited by laser cladding process using different parameters onto the surface of a steel substrate. The obtained coatings were investigated in terms of microstructure, hardness and wear behavior. The experimental results revealed that the laser power had a considerable influence on the wear resistance of NiCrSiFeB coatings.

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