Alkaline Zinc Plating
Gleco offers ASTM B-633 and ASTM B-840 alkaline zinc plating up to 120″ x 36″ x 72″ for those seeking corrosion resistance without excess thickness. Also known as electrolytic zinc coating, alkaline zinc plating uses electrolysis to deposit a burn-free layer of fine-grain zinc on a steel base material in an alkaline medium (basic alkaline pH aqueous solution).
The Plating Process
This process delivers a clear (depending on deposit type), bright, uniform finish with self-healing characteristics that offer outstanding corrosion resistance to protect metals such as carbon steel and brass. It is applied as follows:
- Choose the appropriate zinc plating procedure, rack to ensure no damage to delicate parts, or barrel plating for a more uniform finish.
- Clean the surface to remove any debris or contaminants.
- Prepare the specially formulated electrolyte solution plating bath.
Alkaline Zinc requires less plating efficiency than acid zinc and a slower electrodeposition rate, but it provides superior ductility and uniform thickness.
- Introduce the electrical current to deposit metal ions onto the surface of the metal being plated.
- Apply post-treatment such as rinsing or passivating.
Electrolytic Zinc Coating Color Options
Film color will vary depending on the deposit type it is applied over.
- Colorless Passivate (RoHS Compliant): Clear
- Colored Passivate (RoHS Compliant): Yellow, Black
- Colored Chromates (Non-RoHS Compliant): Yellow, Black, Olive Drab
Benefits of Electroplating Zinc
- A high/low thickness distribution greater than 2:1
- Tight plating tolerances for parts to be bent, crimped, or rolled
- A superior level of throwing power
- Ability to plate over complex geometries and deep recess parts
- Low-current options without extra thickness in the high-current density locations
The Differences Between Alkaline Zinc and Acid Zinc
Alkaline zinc offers excellent thickness distribution with superior throwing power but a lower electro-deposition rate and less plating efficiency, making it ideal for parts with deep recesses or inner dynamics. Acid zinc offers highly-efficient, fast deposition with excellent covering power but weak thickness distribution and poor throwing power, making it ideal for heat-treated steel parts.
Alkaline Zinc plating is used by the automotive, medical, defense, industrial, and aerospace industries to coat:
- Brake systems
- Fuel systems
- Transmission systems
- Fasteners and latches
- Screws, bolts, and washers
- Mounting brackets
- Medical devices
- Hydraulic fittings
- Dental devices