Additive Manufacturing: Corrosion Proofing by Infusion of Interstitial Solute—Exemplified for Alloy 22

Abstract

The corrosion resistance of Cr-containing alloy parts made by additive manufacturing can be significantly improved by a post-treatment of gas-phase-based infusion of concentrated interstitial solute (carbon and nitrogen). We demonstrate this universal approach for the example of low-temperature nitrocarburization by solid-reagent pyrolysis applied to Alloy 22 (UNS N06022) parts made by laser powderbed fusion. We show that the post-treatment improves the crevice-corrosion resistance of these parts, as well as the corrosion resistance of corresponding parts made from wrought Alloy 22 to surpass the maximum crevice corrosion test temperature specified in ASTM G48-D, whereas non-treated samples typically fail well below. Similarly, cyclic potentiodynamic polarization testing (ASTM G61-86) demonstrates that the post-treatment makes the additively manufactured alloy and the wrought alloy more corrosion-resistant than the non-treated wrought alloy.

Additive Manufacturing Processes in Selected Corrosion Resistant Materials: A State of Knowledge Review

“…However, attending the latest 2022 trends, there is a new concept in discussion related to the corrosion proofing of AM alloy parts. For instance, the low-temperature infusion of interstitial solute, exemplified for a highentropy alloy (Alloy 22) to simulate thermochemical treatment, has been discussed by Illing et al [131]. The post-processing of these parts is carried out through a newly developed process of LTNC-SRP (low-temperature nitrocarburization by solid-reagent pyrolysis).…”

Crevice corrosion behavior and mechanism of laser additive manufacturing nickel-based alloy under wedge-shaped crevice by using wire beam electrode

“…In recent years, LAM plays an important role in the remanufacturing and repairing of engineering parts due to material versatility, rapid molding ability and efficient resource utilization (Li and Kong, 2022; Ni et al , 2019; Zhang et al , 2020). LAM technique as a successful method to prepare the key component of the equipment applied in oil and gas field faces the threat of failure as well (Illing et al , 2023). The generation of crevice corrosion is affected by multiple factors, such as crack types, crack geometry, metal elements and corrosive environment (Cl − concentration, temperature, pH, flow rate, etc.…”