Thermal Spraying of Wear and Corrosion Resistant Surfaces

Wielage, B.; Lampke, Thomas; Grund, Thomas

doi:10.4028/www.scientific.net/kem.384.75

Cited by 5 publications

(4 citation statements)

References 25 publications

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“…In comparison, thermal spraying introduces less heat during the process and is less limited in terms of component dimensions [ 7 ]. Nevertheless, thermal sprayed coatings have higher porosity than galvanic coatings, a lamellar structure and thermally or kinetically induced residual stresses [ 8 ]. Compressive residual stresses are beneficial and increase the fatigue strength of components, while tensile residual stresses lead to degradation [ 9 ].…”

Section: Introductionmentioning

confidence: 99%

Fatigue Assessment of Twin Wire Arc Sprayed and Machine Hammer-Peened ZnAl4 Coatings on S355 JRC+C Substrate

et al. 2022

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Structural elements for applications in maritime environments, especially offshore installations, are subjected to various stresses, such as mechanical loads caused by wind or waves and corrosive attacks, e.g., by seawater, mist and weather. Thermally sprayed ZnAl coatings are often used for maritime applications, mainly due to good corrosion protection properties. Machine hammer peening (MHP) has the potential to increase fatigue and corrosion fatigue resistance of ZnAl coatings by adjusting various material properties such as hardness, porosity and roughness. This study investigates the fatigue behavior of twin wire arc sprayed and MHP post-treated ZnAl4 coatings. Unalloyed steel (S355 JRC+C) was selected as substrate material and tested as a reference. MHP achieved the desired improvements in material properties with increased hardness, decreased roughness and uniform coating thickness. Multiple and constant amplitude tests have been carried out to evaluate the fatigue capability of coating systems. In the high cycle fatigue regime, the additional MHP post-treatment led to an improvement of the lifetime in comparison to pure sandblasted specimens. The surface was identified as a crack initiation point. ZnAl coating and MHP post-treatment are suitable to improve the fatigue behavior in the high cycle fatigue regime compared to uncoated specimens.

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Section: Introductionmentioning

confidence: 99%

Fatigue Assessment of Twin Wire Arc Sprayed and Machine Hammer-Peened ZnAl4 Coatings on S355 JRC+C Substrate

et al. 2022

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“…For the thermal spraying process, the dimensions of the parts to be coated are not limited and the heat supplied is lower than provided during galvanization [10]. The thermal spraying process produces coatings with higher porosity than galvanic coatings, a lamellar structure, and residual stresses [11]. Residual stresses can be introduced thermally or kinetically, whereas high temperatures lead to tensile residual stresses that reduce the fatigue strength of components and higher kinetic energy results in compressive stresses, which are known as beneficial for fatigue strength [12,13].…”

Section: Introductionmentioning

confidence: 99%

Corrosion Fatigue Behavior of Twin Wire Arc Sprayed and Machine Hammer Peened ZnAl4 Coatings on S355 J2C + C Substrate

Milz

Wirtz

Abdulgader

et al. 2022

CMD

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Offshore installations, e.g., offshore wind turbines and pipelines, are exposed to various mechanical loads due to wind or waves and corrosive loads such as seawater or mist. ZnAlbased thermal sprayed coatings, often in conjunction with organic coatings, provide sufficient corrosion protection and are well established for applications in marine environments. In this study, machine hammer peening (MHP) is applied after twin wire arc spraying to improve corrosion fatigue behavior through increased hardness, reduced porosity, and roughness compared to as-sprayed coatings. Mn-alloyed structural steel S355 J2 + C with and without ZnAl4 coating as well as with MHP posttreated ZnAl4 coating were cyclically loaded in 3.5% NaCl solution. MHP leads to a uniform coating thickness with lower porosity and roughness. ZnAl4 coating and MHP post-treatment improved corrosion fatigue behavior in the high cycle fatigue regime with an increase of the stress amplitude, applied to reach a number of cycles 1.2 × 106, up to 115% compared to sandblasted specimens. Corrosive attack of the substrate steel was successfully avoided by using the coating systems. Stress- and microstructure-dependent corrosion fatigue damage mechanisms were evaluated by mechanical and electrochemical measurement techniques.

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“…Disadvantages of thermally sprayed coatings compared to galvanic coatings include often-higher porosities [11], heterogeneous compositions, lamellar layered microstructures, and thermally or kinetically induced residual stresses. Depending on the inherent process characteristics, the induced residual stresses include tensile residual stresses [12] in the case of higher temperatures, and compressive residual stresses [13] in case of higher kinetic energy process types.…”

Section: Introductionmentioning

confidence: 99%

Thermally Assisted Machine Hammer Peening of Arc-Sprayed ZnAl-Based Corrosion Protective Coatings

Wirtz

Abdulgader

Milz

et al. 2021

JMMP

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Structural elements of offshore facilities, e.g., offshore wind turbines, are subject to static and dynamic mechanical and environmental loads, for example, from wind, waves, and corrosive media. Protective coatings such as thermal sprayed ZnAl coatings are often used for protection, mainly against corrosive stresses. The Machine Hammer Peening (MHP) process is an innovative and promising technique for the post-treatment of ZnAl coating systems that helps reducing roughness and porosity and inducing compressive residual stresses. This should lead to an enhancement of the corrosion fatigue behavior. In this paper, the effect of a thermally assisted MHP process was investigated. The softening of the coating materials will have a direct effect on the densification, residual porosity and the distribution of cracks. The investigation results showed the influence of thermally assisted MHP on the surface properties, porosity, residual stresses, and hardness of the post-treated coatings. The best densification of the coating, i.e., the lowest porosity and roughness and the highest compressive residual stresses, were achieved at a process temperature of 300 °C. A further increase in temperature on the other hand caused a higher porosity and, in some cases, locally restricted melting of the coating and consequently poorer coating properties.

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Thermal Spraying of Wear and Corrosion Resistant Surfaces

Cited by 5 publications

References 25 publications

Fatigue Assessment of Twin Wire Arc Sprayed and Machine Hammer-Peened ZnAl4 Coatings on S355 JRC+C Substrate

Fatigue Assessment of Twin Wire Arc Sprayed and Machine Hammer-Peened ZnAl4 Coatings on S355 JRC+C Substrate

Corrosion Fatigue Behavior of Twin Wire Arc Sprayed and Machine Hammer Peened ZnAl4 Coatings on S355 J2C + C Substrate

Thermally Assisted Machine Hammer Peening of Arc-Sprayed ZnAl-Based Corrosion Protective Coatings

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