SURFACE FINISHING AND ELECTROLESS NICKEL PLATING OF ADDITIVELY MANUFACTURED (AM) METAL COMPONENTS
This study investigates the application of electroless nickel deposition on additively manufactured stainless steel samples. Current additive manufacturing (AM) technologies produce metal components with a rough surface. Rough surfaces generally exhibit fatigue characteristics, increasing the probability of initiating a crack or fracture to the printed part. For this reason, the direct use of as-produced parts in a finished product cannot be actualized, which presents a challenge. Post-processing of the AM parts is therefore required to smoothen the surface. This study analyzes Chempolishing (CP) and Electropolish (EP) surface finishing techniques for post-process of the AM stainless steel components. CP is a pure chemical process in which the solution continually anodized the sample where oxidation-reduction occurs. CP has a great advantage in creating uniform, smooth surfaces regardless of size or part geometry. EP is an electro-chemical process that requires an electric current for polishing to happen. EP creates an extremely smooth surface, which reduces the surface roughness to the sub-micrometer level. Further in this study, we investigate nickel deposition on EP, CP, and as-built AM components using electroless nickel solutions. Electroless nickel plating is a method of alloy treatment designed to increase manufactured component's hardness and surface resistance to the unrelenting environment. The electroless nickel plating process is more straightforward than its counterpart electroplating. There is no need to use an electric current through the chemical bath solution to nickel deposition happened. for this study. We use low-phosphorus (2-5% P), medium-phosphorus (6-9% P), and high-phosphorus (10-13% P). These Ni deposition experiments were optimized using the L9 Taguchi design of experiments (TDOE), which compromises the prosperous content in the solution, surface finish, plane of the geometry, and bath temperature. The pre-and post-processed surface of the AM parts was characterized by KEYENCE Digital MicroscopeVHX-7000 and Phenom XL Desktop SEM. The experimental results show that electroless nickel deposition produces uniform Ni coating on the additively manufactured components up to 20 µm per hour. Mechanical properties of as-built and Ni coated AM samples were analyzed by applying a standard 10 N scratch test. Nickel coated AM samples were up to two times scratch resistant compared to the as-built samples. This study suggests electroless nickel plating is a robust viable option for surface hardening and finishing AM components for various applications and operating conditions. KeyWords: Additive manufacture, fatigue, chempolishing, electropolish, plating, hardness, Taguchi design of experiments, surface finish.
- Research Organization:
- Kansas City Nuclear Security Campus (KCNSC), Kansas City, MO (United States)
- Sponsoring Organization:
- USDOE National Nuclear Security Administration (NNSA)
- DOE Contract Number:
- DE-NA0002839
- OSTI ID:
- 1810277
- Report Number(s):
- NSC-614-3686
- Resource Relation:
- Conference: Proceedings of the ASME 2021 International Mechanical Engineering Congress and Exposition IMECE2021 November 1-5, 2021, Virtual, Online
- Country of Publication:
- United States
- Language:
- English
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