Reflectivity and laser irradiation of plasma sprayed Al coating

2015 ◽  
Author(s):  
Lihong Gao ◽  
Zhuang Ma ◽  
Fuchi Wang ◽  
Wenzhi Li
Keyword(s):  
Laser Irradiation ◽  
Plasma Sprayed ◽  
Al Coating

scholarly journals Ni–Al Protective Coating of Steel Electrodes in Dc Electrolysis for Hydrogen Production / Ni–Al Pārklājuma Ietekme Uz Tērauda Elektrodiem Līdzstrāvas Elektrolīzē Ūdeņraža Ražošanai

2013 ◽  
Vol 50 (2) ◽  
pp. 53-59 ◽  
Author(s):  
P. Aizpurietis ◽  
M. Vanags ◽  
J. Kleperis ◽  
G. Bajars
Keyword(s):  
Hydrogen Production ◽  
Protective Coating ◽  
Fossil Fuels ◽  
Water Electrolysis ◽  
Good Alternative ◽  
Production Water ◽  
316L Steel ◽  
Plasma Sprayed ◽  
Al Coating ◽  
Steel Electrodes

Hydrogen can be a good alternative to fossil fuels under the conditions of world's crisis as an effective energy carrier derived from renewable resources. Among all the known methods of hydrogen production, water electrolysis gives the ecologically purest hydrogen, so it is of importance to maximize the efficiency of this process. The authors consider the influence of plasma sprayed Ni-Al protective coating of 316L steel anode-cathode electrodes in DC electrolysis. In a long-term (24 h) process the anode corrodes strongly, losing Cr and Ni ions which are transferred to the electrolyte, while only minor corrosion of the cathode occurs. At the same time, the composition of anode and cathode electrodes protected by Ni-Al coating changes only slightly during a prolonged electrolysis. As the voltammetry and Tafel plots evidence, the Ni-Al coating protects both the anode and cathode from the corrosion and reduces the potential of hydrogen evolution. The results obtained show that such a coating works best in the case of steel electrodes.

Studies on erosion-corrosion behaviour of plasma sprayed Ni3Al coating in a coal-fired thermal power plant environment at 540°C

2017 ◽  
Vol 64 (5) ◽  
pp. 540-549 ◽  
Author(s):  
S.B. Mishra ◽  
Kamlesh Chandra ◽  
Satya Prakash
Keyword(s):  
Power Plant ◽  
Thermal Power Plant ◽  
Nickel Aluminide ◽  
Corrosion Behaviour ◽  
Thermal Power ◽  
Content Type ◽  
Erosion Corrosion ◽  
Boiler Environment ◽  
Plasma Sprayed ◽  
Al Coating

Purpose The purpose of this study is to investigate the application of Ni3Al coating for boilers and other power plant equipment, which suffer severe erosion-corrosion problems resulting in substantial losses. Currently, superalloys are being used to increase the service life of the boilers. Although the superalloys have adequate mechanical strength at elevated temperature, they often lack resistance to erosion-corrosion environments. Design/methodology/approach In this paper, the erosion-corrosion performance of plasma-sprayed nickel aluminide (Ni3Al) coating on nickel- and iron-based superalloys have been evaluated by exposing them to the low temperature primary superheater zone of the coal-fired thermal power plant at the temperature zone of 540°C for ten cycles of 100 h duration. The exposed products were analysed along the surface and cross-section using scanning electron microscopy (SEM), X-ray diffraction (XRD) and electron micro probe analysis (EPMA). Findings The XRD, SEM and EPMA analyses have shown the formation of mainly NiO, NiAl2O4 and indicated the presence of Ni3Al, Ni and Al2O3. In the boiler environment, Ni3Al coating partially oxidizes and acts as a perfect barrier against erosion-corrosion of superalloys. The partially oxidised Ni3Al coating remains intact even after 1,000 h cycle exposure. Originality/value The probable mechanism of attack for the plasma-sprayed Ni3Al coating in the given boiler environment is presented.

Comparison of laser irradiation behavior of plasma-sprayed Ba2−XSrxSmTaO6 coatings

2021 ◽  
Vol 33 (1) ◽  
pp. 012050
Author(s):  
Jiayi Zheng ◽  
Zhuang Ma ◽  
Yanbo Liu ◽  
Lihong Gao ◽  
Alexandr A. Rogachev
Keyword(s):  
Laser Irradiation ◽  
Plasma Sprayed ◽  
Irradiation Behavior

NiCrAlY Coatings in Yag Laser Combined Low Pressure Plasma Spraying

1998 ◽  
Author(s):  
N. Eguchi ◽  
Z. Zhou ◽  
H. Shirasawa ◽  
A. Ohmori
Keyword(s):  
Laser Irradiation ◽  
Steel Substrate ◽  
High Hardness ◽  
Low Pressure ◽  
Yag Laser ◽  
Pressure Plasma ◽  
Low Pressure Plasma ◽  
Porous Microstructure ◽  
Sprayed Coating ◽  
Plasma Sprayed

Abstract Densification of plasma sprayed NiCrAlY coatings was studied from the view point of hybrid spraying combined with YAG laser irradiation. Configuration of a laser irradiation beam was varied in three different ways while performing low pressure plasma hybrid spraying and the microstructure of each coating was investigated in comparison with a conventional plasma sprayed coating. Of the three types of hybrid spraying, namely, (D pre-laser-irradiation for preheating of a steel substrate, ©simultaneous laser irradiation, and (3) post-laser-irradiation for remelting of the plasma sprayed coating, simultaneous irradiation formed the optimum microstructure showing both the least amount of porosities and high hardness. Some metallurgical bonding was also observed at the interface with this type of spraying. The two other types of hybrid spraying resulted in either a significantly porous microstructure with pre-irradiation, or a low hardness coating with post-irradiation. The characteristics of these microstructures in each coating are explained with reference to thermal hysterisis behaviors.

Laser irradiation behavior of plasma-sprayed tantalum oxide coatings

2020 ◽  
Vol 46 (3) ◽  
pp. 3875-3881
Author(s):  
Jiayi Zheng ◽  
Kang Wen ◽  
Yanbo Liu ◽  
Lihong Gao ◽  
Zhuang Ma ◽  
...  
Keyword(s):  
Laser Irradiation ◽  
Tantalum Oxide ◽  
Oxide Coatings ◽  
Plasma Sprayed ◽  
Irradiation Behavior

scholarly journals Suppression of molten salt corrosion by plasma sprayed Ni3Al coatings

2021 ◽  
Author(s):  
Sarah Yasir ◽  
Jose Luis Endrino ◽  
Elena Guillén ◽  
Adrianus Indrat Aria
Keyword(s):  
Stainless Steel ◽  
Corrosion Rate ◽  
Corrosion Behaviour ◽  
Stainless Steel Surface ◽  
Air Plasma ◽  
Oxide Layers ◽  
Salt Corrosion ◽  
Plasma Sprayed ◽  
Steel Substrates ◽  
Al Coating

AbstractCorrosion behaviour of stainless steel 347 was investigated in a molten nitrate salt (60 wt% NaNO3 + 40 wt% KNO3) immersion at 565 °C for up to 3000 h. A growth of stratified oxide layers consisting of NaFeO2, Fe2O3 and Fe3O4 was observed on the stainless steel surface with a constant gravimetric corrosion rate of ~ 0.4 µm/year. The feasibility of using Ni3Al coatings deposited by means of air plasma spray for suppression of corrosion was investigated. Ni3Al coatings were observed to undergo a fast oxidation with a corrosion rate of ~ 2.7 µm/year in the first 500 h, and subsequently stabilise between 500 and 3000 h with no observable changes in microstructure, composition and weight at a corrosion rate of ~ 0.02 µm/year. The results presented in this study strongly suggest that Ni3Al coating suppresses the formation of oxide layers on the surface of stainless steel substrates and can be used as protection against corrosion in the presence of molten nitrate salts, which is of relevance to thermal energy storage applications.

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