Selective or brush plating is an application method for electrodeposition which can be used for depositing an array of pure metals, alloys, and composite materials onto conductive surfaces. Brush plating has seen its most advantageous use in plating smaller areas of larger parts because the amount of masking used can be reduced, and smaller volumes of solution can be utilized compared to traditional tank plating methods. These same characteristics make brush plating portable and repair operations can be conducted in the field, at times without even disassembling equipment. Brush plating is currently used across a multitude of industrial applications in the fields of aerospace, oil and gas, marine environments, semiconductors, and other manufacturing.

‘Brush’ plating is often considered a manual technique where a technician directly applies the anode (wrapped in the ‘brush’ material) to the surface to be plated. The brush material must be a porous, non-conductive, flexible material which electrically separates the anode from the surface to be plated. The plating solution is absorbed into the brush material around the anode prior to plating by dipping it into a vessel containing the solution. Alternatively, solution can be pumped directly through the anode to the surface to be plated. As a result, smaller volumes of solution can be used because the entire part is not immersed in a large tank containing the plating solution. Masking can be placed around the area to be plated without needing to mask off every surface that isn’t receiving a deposit.

The current density used for brush plating is often high (0.2 to 1.5 A/cm²) relative to other electrochemical plating techniques. Brush plating solutions are typically highly concentrated and the brushing action against the surface where deposition is occurring allows for replenishment of the ion to be plated very close to the interface with the cathode. This allows for high plating rates (Up to 500 µm/hr) depending on the solution and other plating parameters utilized.

This presentation will introduce the audience to the brush plating technique through the use of current and classical applications with multiple deposits. Pros and cons of the technique for different circumstances will be discussed. The influence of the brush material on the electrochemical interface during plating and the resulting deposit will be highlighted. Current research includes the development of deposits for chrome alternatives, alloys for corrosion resistance, and applying deposits to challenging substrates.