Presented here is a protocol of bathless electroplating, where a stagnant metal salt paste containing composite particles are reduced to form metal composites at high loading. This method addresses the challenges faced by other common forms of electroplating (jet, brush, bath) of embedding composites particles into the metal matrix.
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Method Article
Localized Bathless Metal-Composite Plating via Electrostamping
* These authors contributed equally
In This Article
Summary
Abstract
Composite plating with particles embedded into the metal matrix can enhance the properties of the metal coating to make it more or less conductive, hard, durable, lubricated or fluorescent. However, it can be more challenging than metal plating, because the composite particles are either 1) not charged so they do not have a strong electrostatic attraction to the cathode, 2) are hygroscopic and are blocked by a hydration shell, or 3) too large to remain stagnate at the cathode while stirring. Here, we describe the details of a bathless plating method that involves anode and cathode nickel plates sandwiching an aqueous concentrated electrolyte paste containing large hygroscopic phosphorescent particles and a hydrophilic membrane. After applying a potential, the nickel metal is deposited around the stagnant phosphor particles, trapping them in the film. The composite coatings are characterized by optical microscopy for film roughness, thickness and composite surface loading. In addition, fluorescence spectroscopy can be used to quantify the illumination brightness of these films to assess the effects of various current densities, coating duration and phosphor loading.
Introduction
Traditional electroplating is widely used to deposit thin films of a variety of metals, alloys, and metal-composites onto conductive surfaces to functionalize them for the intended application1,2,3,4,5,6,7,8,9,10,11,12. This method adds a metal finish to parts used i....
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Protocol
1. Preparing coating salts
CAUTION: Nickel salts and boric acid are toxic and should be handled with proper personal protective equipment including nitrile gloves, goggles and a lab coat. Strong acids and bases should be handled in the fume hood, and all waste chemicals should be disposed of as hazardous waste.
- Using a balance, weigh out the following powders in these ratios: 10.000 g of NiSO4·6H2O, 2.120 g of NiCl2·6H2O, 1.600 g of H3BO3 and combine in a vial together. See Table 1 for concentrations.
- Weigh out 1.800 g of SrAl2
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Results
After following this protocol, a thin coating of metal should become plated onto the cathode surface and contain the composite particles that were added to the coating paste. Fluorescent or colored particle incorporation can be observed by visual inspection as a result of a change in appearance compared to the uncoated surface (Figure 1A1-A3). To investigate the percent surface coverage of the composite particles and to observe the surface morphology of the coating, optical .......
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Discussion
Critical steps of electrostamping. Bathless electrostamping shares many of the same critical steps with traditional bath electroplating. These include proper cleaning of the electrodes, mixing metal ions into the electrolyte and applying and external or chemical (electroless plating) potential to cause reduction of metal onto the cathode. In addition, the oxidation of the anode and cathode should be avoided after acid activation by quickly rinsing with water and adding these electrodes to the setup.
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Disclosures
The authors have nothing to disclose.
Acknowledgements
This work was supported by the Aircraft Equipment Reliability and Maintainability Improvement Program and the Patuxent Partnership. Townsend was supported by an ONR Faculty Research Fellowship. The authors also acknowledge the general support of the SMCM Chemistry and Biochemistry Department faculty and students, including support from the SMCM football team.
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Materials
| Name | Company | Catalog Number | Comments |
|---|---|---|---|
| 37% M Hydrochloric Acid (aq) | SigmaAldrich | 320331-500ML | corrosive - handle in fume hood |
| 70% Nitric Acid (aq) | SigmaAldrich | 438073-500ML | corrosive - handle in fume hood |
| Barium magnesium aluminate, europium doped (s) | SigmaAldrich | 756512-25G | fine powder |
| Boric Acid (s) | SigmaAldrich | B6768-500G | toxic |
| Cotton Swab | Q-tips | Q-tips Cotton Swabs | |
| ImageJ | National Institutes of Health | IJ 1.46r | free software |
| Nickel (II) chloride hexahydrate (s) | SigmaAldrich | 223387-500G | toxic |
| Nickel (II) sulfate hexahydrate (s) | SigmaAldrich | 227676-500G | toxic |
| Nickel foil (s) | AliExpress | Ni99.999 | |
| Nitrile gloves | Fisher Scientific | 19-149-863B | |
| nylon membrane (s) | Tisch Scientific | RS10133 | |
| Optical Microscope equipped with FTIC filter (470 ± 20 nm) | Nikon | Eclipse 80i | |
| Plastic Wrap | Fisher Scientific | 22-305654 | |
| Porcelain Mortar | Fisher Scientific | FB961A | |
| Porcelain Pestle | Fisher Scientific | FB961K | |
| Potassium Hydroxide (s) | SigmaAldrich | 221473-25G | corrosive |
| Potentiostat with platinum wire | Gamry Instruments | 1000E | |
| Scoopula | Fisher Scientific | 14-357Q | |
| Spectrofluorometer | Photon Technology International | QM-40 | |
| Strontium aluminate, europium and dysprosium doped (s) | GloNation | 756539-25G | powder |
| Variable linear DC power supply | Tekpower | TP3005T | |
| Yttrium oxide, europium doped (s) | SigmaAldrich | 756490-25G | fine powder |
References
- Hunt, W. H., et al. Comprehensive Composite Materials. , Elsevier Ltd. (2000).
- Hovestad, A., Janssen, L. J. J. Electrochemical codeposition of inert particles in a metallic matrix. Journal of Applied Electrochemistry. 25 (6), 519-527 (1995).
- Zimmerman, A. F., Clark, D. G., Au....
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