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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 chempolish (CP) and electropolish (EP) surface finishing techniques for post-processing AM stainless steel components CP has a great advantage in creating uniform, smooth surfaces regardless of size or part geometry EP creates an extremely smooth surface, which reduces the surface roughness to the sub-micrometer level. In this study, we also 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. 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.
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Proof‐of‐Concept Roll‐to‐Roll Fabrication of Antimicrobial Textiles by Polydopamine‐Assisted Electroless Silver Plating
ABSTRACT Silver (Ag) is widely used for antimicrobial textiles due to its strong biocidal activity, but conventional Ag coating methods are often expensive and involve complex processing steps. In this study, we present a simple, solution‐based approach using polydopamine (PDA)‐assisted electroless Ag plating, which enables uniform Ag deposition on textiles with improved scalability. We systematically investigate the effects of pH, temperature, and oxygen concentration on the growth kinetics of Ag nanoparticles (NPs) during PDA‐assisted electroless Ag plating. Results show that elevated temperature (65°C), alkaline solution (pH = 10), and increased oxygen purging (50 sccm) each significantly accelerates Ag NP deposition, with coverage up to 56.69% and particle sizes up to 69.48 ± 14.89 nm. Optical and structural analyses confirmed enhanced PDA deposition as the key to expediting Ag NP growth on various textiles. Using this accelerated process, we developed a cost‐effective, 3D‐printed roll‐to‐roll system to scale up fabrication, achieving rapid and uniform Ag NP deposition. The resulting textiles exhibited superior antimicrobial properties, offering an affordable and effective solution for high‐performance hygiene applications.
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- Award ID(s):
- 2114052
- PAR ID:
- 10643800
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- SPE Polymers
- Volume:
- 6
- Issue:
- 4
- ISSN:
- 2690-3857
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract This research investigates the feasibility of electroless nickel deposition on additively manufactured stainless steel samples. The prevalent additive manufacturing techniques for metal components generate a surface with rough characteristics, which can result in a higher likelihood of fatigue and the initiation of cracks or fractures in the printed part. As a result, using as-manufactured components in the final product is impractical, which requires post-processing to create a smoother surface. This study assesses chempolishing (CP) and Electropolish (EP) techniques for post-processing additively manufactured stainless steel components. CP is a purely chemical process that involves continuous anodization of the sample, resulting in oxidation-reduction. CP has a significant advantage in creating a uniform and smooth surface, irrespective of the size or geometry of the component. Conversely, EP is an electrochemical process that necessitates an electric current to facilitate polishing. EP produces an exceptionally smooth surface that reduces surface roughness to a sub-micrometer level. We observed that EP and CP techniques reduced the surface roughness’s arithmetical mean height (Ra) by up to 4 μm and 10 μm, respectively. In this study, we investigate the application of electroless nickel deposition on additively manufactured (AM) components using different surface finishing techniques, including electro-polishing (EP), chemo-polishing (CP), and as-built components. Electroless nickel plating aims to enhance the surface hardness and resistance of manufactured components to withstand harsh environmental conditions. The electroless nickel plating process is less complicated than electroplating and does not require using an electric current through the chemical bath solution for nickel deposition. For this study, we used low-phosphorus (2–5% P), medium-phosphorus (6–9% P), and high-phosphorus (10–13% P) nickel solutions. We used the L9 Taguchi design of experiments (TDOE) to optimize these Ni deposition experiments, which consider solution content, surface finish, geometry plane, and bath temperature. The pre- and post-processed surfaces of the AM parts were analyzed using the KEYENCE Digital Microscope VHX-7000 and Phenom XL Desktop SEM. We apply a machine learning-based instance segmentation technique to improve the identification of nickel deposition and surface topology of microscopic images. Our experiments show that electroless nickel deposition produces uniform Ni coating on the additively manufactured components at up to 20 μm per hour. Mechanical properties of as-built and Ni-coated AM samples were evaluated using a standard 10 N scratch test. It was found that the nickel-coated AM samples were up to two times more scratch-resistant than the as-built samples. Based on our findings, we conclude that electroless nickel plating is a robust and viable option for surface hardening and finishing AM components for various applications and operating conditions.more » « less
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