TY - JOUR

T1 - Young’s Modulus and Residual Stresses of Oxide-Free Wire Arc Sprayed Copper Coatings

AU - Rodriguez Diaz, Manuel

AU - Raumel, Selina

AU - Wurz, Marc Christopher

AU - Szafarska, Maik

AU - Gustus, René

AU - Möhwald, Kai

AU - Maier, Hans Jürgen

N1 - Funding Information: This project is funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation), Project-ID 394563137–SFB 1368.

PY - 2022/10/6

Y1 - 2022/10/6

N2 - Conventional thermal spraying processes are almost exclusively carried out in an air atmosphere, resulting in the oxidation of the particle surfaces and interfaces within the coating and between the substrate and coating. Furthermore, the initial process of surface activation conventionally takes place in an air atmosphere, preventing an oxide-free interfacial transition. Consequently, the application of spraying materials with high oxygen affinity represents a major challenge. To overcome these issues, the present study utilized silane-doped inert gases to create an environment in which the oxygen concentration was equivalent to the residual oxygen content in an extreme high vacuum. By transferring the corundum blasting and coating process (wire arc spraying) to this environment, materials with a high oxygen affinity can be applied without oxidation occurring. For industrial use, this is an interesting prospect, e.g., for repair coatings, as the homogeneity of the composite is improved by a non-oxidized coating. Using the example of arc-sprayed copper coatings, the microstructure and mechanical properties of the coatings were analysed. The results showed that the oxide-free, wire arc sprayed copper coatings exhibited an improved wetting behaviour resulting in a significant reduction of the coating porosity. Moreover, the improved wetting behaviour and led to an increase in the bonding rate and apparent Young’s modulus. Contrary to expectations, the residual stresses decrease although relaxation mechanisms should be inhibited, and possible reasons for this are discussed in the paper.

AB - Conventional thermal spraying processes are almost exclusively carried out in an air atmosphere, resulting in the oxidation of the particle surfaces and interfaces within the coating and between the substrate and coating. Furthermore, the initial process of surface activation conventionally takes place in an air atmosphere, preventing an oxide-free interfacial transition. Consequently, the application of spraying materials with high oxygen affinity represents a major challenge. To overcome these issues, the present study utilized silane-doped inert gases to create an environment in which the oxygen concentration was equivalent to the residual oxygen content in an extreme high vacuum. By transferring the corundum blasting and coating process (wire arc spraying) to this environment, materials with a high oxygen affinity can be applied without oxidation occurring. For industrial use, this is an interesting prospect, e.g., for repair coatings, as the homogeneity of the composite is improved by a non-oxidized coating. Using the example of arc-sprayed copper coatings, the microstructure and mechanical properties of the coatings were analysed. The results showed that the oxide-free, wire arc sprayed copper coatings exhibited an improved wetting behaviour resulting in a significant reduction of the coating porosity. Moreover, the improved wetting behaviour and led to an increase in the bonding rate and apparent Young’s modulus. Contrary to expectations, the residual stresses decrease although relaxation mechanisms should be inhibited, and possible reasons for this are discussed in the paper.

KW - oxygen-free

KW - residual stresses

KW - wire arc spraying

UR - http://www.scopus.com/inward/record.url?scp=85140897280&partnerID=8YFLogxK

U2 - 10.3390/coatings12101482

DO - 10.3390/coatings12101482

M3 - Article

AN - SCOPUS:85140897280

VL - 12

JO - COATINGS

JF - COATINGS

SN - 2079-6412

IS - 10

M1 - 1482

ER -