scholarly journals Microstructure and Corrosion Behavior of Laser-Cladding CeO2-Doped Ni-Based Composite Coatings on TC4

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Fangxia Ye ◽  
Wenxuan Shao ◽  
Xuchao Ye ◽  
Mingxia Liu ◽  
Yanxiang Xie ◽  
...  

Laser-cladding CeO2-doped Ni-based composite coatings were prepared on the surface of a titanium alloy, and the effects of CeO2 addition on the microstructure, microhardness, and corrosion resistance of the prepared coatings were studied. The results showed that TiC, NiTi, Ni3Ti, and Ti2Ni phases were formed on the prepared coatings. Moreover, the addition of CeO2 in laser-cladding coatings effectively refined the microstructure and reduced the number of cracks generated in the laser-cladding process. When the amount of CeO2 was 2%, the number of cracks in the laser-cladding coating was significantly reduced compared with that of 0%. When the content of CeO2 was 2% or 3%, the microhardness of laser-cladding coatings reached the maximum value. At the same time, it was found that the appropriate addition of CeO2 was helpful to improve the corrosion resistance of the laser-cladding coating. However, excessive CeO2 addition could reduce the corrosion resistance of the laser-cladding coating.

2020 ◽  
Vol 143 (1) ◽  
Author(s):  
Guangyu Han ◽  
Youfeng Zhang

Abstract Composite coatings of TiB were successfully obtained on the surface of a Ti–6Al–4V alloy by in situ laser cladding technology using Ti/B/Nd2O3 powders. The microstructure and corrosion resistance of the fabricated composite coatings were investigated because relevant studies have been thus far limited in this field. The results indicate that the cladding coating and the substrate combined well via metallurgy after laser cladding treatment, and no obvious cracks were observed in the cladding coatings. The coatings comprise only the TiB and the α-Ti phase. The addition of Nd2O3 promoted the formation of a uniform and refined microstructure of the cladding coatings, and a well-defined structure was obtained when the added Nd2O3 content was 2 wt%. The microhardness of the cladding coating obviously improved by 3 to 4 fold above that of the Ti–6Al–4V substrate. Moreover, the corrosion properties significantly improved by adding Nd2O3 into the coatings. Electrical impedance spectroscopy and polarization tests showed that the best corrosion resistance of the cladding coating was achieved with the addition of 2 wt% Nd2O3. All samples revealed obvious near-capacitive behavior after immersion in a corrosive medium.


2013 ◽  
Vol 634-638 ◽  
pp. 2973-2978 ◽  
Author(s):  
Huan He ◽  
Yue Chun Fu ◽  
Wei Hua Guo ◽  
Min Xiao ◽  
Xing Zhi Pang ◽  
...  

Intermetallic compound Al3Ti-based IMC coatings were formed on AA6063 aluminum alloy by laser cladding. The microstructure and corrosion characteristics in 3.5% NaCl solution were investigated. The results show that, the laser cladding coating is made up of Al3Ti dendrites, interdendritic α-Al and uniform distribution of TiC which hardly melted during laser irradiation, and shows good bonding to the substrate. The cross distribution of Al3Ti and α-Al helps to avoid the generation of cracks in the coating. The corrosion resistance of the laser cladding coatings is greatly increased as compared with the substrate, which owes mainly to the existence of hard Al3Ti and TiC. And with the increasing of TiC content in the coating, the corrosion resistance is improved simultaneously.


Coatings ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 849
Author(s):  
Chao Zheng ◽  
Zongde Liu ◽  
Shanshan Chen ◽  
Congcong Liu

For this study, aimed at proposing a potential direction to prevent sulfuric acid dew point corrosion, a Ni–Cr–Mo alloy Hastelloy C22 coating was fabricated by coaxial laser cladding technology. The phase composition, microstructure, and corrosion behavior in a simulated sulfuric acid dew point corrosion environment were investigated and compared with a Hastelloy C22 alloy, a titanium alloy TC4, and 09CrCuSb steel (ND). The results showed that the phase composition of the C22 coating is essentially similar to that of the C22 alloy, consisting of a γ-Ni solid solution and Ni6Mo6C1.06. The finer microstructure of the C22 coating mainly contains eutectic and dentrite, presenting a typical solidification feature of laser cladding. The corrosion resistance of the C22 coating is very close to that of the C22 alloy, and outclasses that of TC4 and ND. The corrosion behavior of the C22 coating is intergranular corrosion resulting from the segregation of molybdenum, chromium containing corrosion products, and smaller anode micro-batteries.


Author(s):  
Simona BOICIUC ◽  
◽  
◽  

The undertaken research which is described in this paper aims at the corrosion behaviour of composite coatings in nickel matrix using as dispersed phase technical alumina with dimensions of 5 μm and their characterization from a microstructural point of view. The corrosion resistance in the saline fog of the coatings is influenced by the microstructure, the stresses developed in the layer and the roughness.


Author(s):  
Lei Che

Laser cladding technology is highly suitable for the remanufacturing of thin-walled and easily deformable parts due to its concentrated energy density. Due to the high temperature and high pressure corrosion environment, the valve sealing surface is prone to corrosion, wear and other failures. A nickel-based tungsten carbide alloy layer was prepared on the valve sealing surface substrate material by laser cladding process. By designing orthogonal experiments, the effects of laser power (P), scanning speed (Vb), powder feeding rate (Vf), and WC content (wt%) on the alloy layer were investigated. A fuzzy comprehensive evaluation method including macroscopic quality, microstructure, microhardness, anti-wear performance, oxidation resistance, compactness and corrosion resistance was proposed. The experimental results showed that the hardness, oxidation resistance and corrosion resistance of the laser alloy layer are significantly improved compared with the matrix; the optimum process parameters and the addition ratio of WC powder are laser power (P) of 1.1 kW and scanning speed (Vb) of 800 mm/min. The powder feeding rate (Vf) was 20%, and the WC content was 20% by weight.


Applied laser ◽  
2014 ◽  
Vol 34 (5) ◽  
pp. 383-388
Author(s):  
相占凤 Xiang Zhanfeng ◽  
刘秀波 Liu Xiubo ◽  
罗健 Luo Jian ◽  
任佳 Ren Jia ◽  
石皋莲 Shi Gaolian ◽  
...  

2021 ◽  
Vol 47 (2) ◽  
pp. 2230-2243
Author(s):  
Ya'nan Liu ◽  
Lijun Yang ◽  
Xuejiao Yang ◽  
Tiangang Zhang ◽  
Ronglu Sun

2016 ◽  
Vol 254 ◽  
pp. 290-295
Author(s):  
Iosif Hulka ◽  
Ion Dragoş Uţu ◽  
Viorel Aurel Şerban ◽  
Alexandru Pascu ◽  
Ionut Claudiu Roată

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.


2012 ◽  
Vol 19 (02) ◽  
pp. 1250009 ◽  
Author(s):  
PENG LIU ◽  
WEI GUO ◽  
DAKUI HU ◽  
HUI LUO ◽  
YUANBIN ZHANG

The synthesis of hard composite coating on titanium alloy by laser cladding of Al/Fe/Ni+C/Si3N4 pre-placed powders has been investigated in detail. SEM result indicated that a composite coating with metallurgical joint to the substrate was formed. XRD result indicated that the composite coating mainly consisted of γ- (Fe, Ni) , FeAl , Ti3Al , TiC , TiNi , TiC0.3N0.7 , Ti2N , SiC , Ti5Si3 and TiNi . Compared with Ti-3Al-2V substrate, an improvement of the micro-hardness and the wear resistance was observed for this composite coating.


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