Services & Finishes

UniMetal has the unique capabilities in the world of both Precious Metal and Commercial Finishing.  Service for products in such field as Electronics, Medical, Aerospace, Automotive and Hardware, as well as other related industries is provided.

Electroplating Process

Electroplating, also known as Electrodeposition, is essentially the process of producing a coating, usually metallic layer, onto an electrically conductive substrate. This process is performed using an aqueous metallic salt solution called “electrochemical cell”, which contain dissolved metal and other additives. Electroplating can use a large selection of metals including brass, bronze, cadmium, copper, chromium, gold, nickel, platinum, silver, tin, zinc and others.

Electrolytic Cell Components:

1. Cathode
2. Anode
3. Plating Bath
4. Rectifier (Amperage, Volt)
5. Time
6. Positive Charged Ions

Controlling parameters such as voltage, amperage, temperature, running times and solution concentration, the metal or substrate being plated act as cathode (negative pole), attracting ions from the solution cell discharged trough the anode (positive pole). This process of forming a homogeneous layer of metal at the surface of the substrate is achieved by using a Rectifier to supply the current intensity capable of transform electrical energy into chemical energy, providing electrons to reduce the positively charged ions to metallic form. The thickness of the electroplated layer is determined by the plating time.

Metal Finishing Creates a New Surface on the Metal Products to Enhance:

• Corrosion protection
• Wear resistance
• Electrical conductivity
• Electrical resistance
• Reflectivity and appearance (e.g., brightness or color)
• Hardness
• Torque tolerance
• Solderability
• Tarnish resistance
• Chemical resistance

MIRALLOY® Alternatives

• Alternatives to silver coatings with good solderability and weldablity
• Barrel and rack plating electrolyte for functional applications
• Copper-tine-(zinc) electrolytes as nickel-free alternatives
  

Plating Sequence

The sequence of operation in an electroplating process is alike in both rack and barrel plating operations.

Typical Electroplating Process

Sequence Involves Various Phases of Cleaning, Rinsing, Plating and Post-Plating Treatment

Cleaning Process

(Steps 1, 2, 4): used to remove Soil from the surface of the parts (lubricants, cutting oil, wax, rust preventive, organic or inorganic film). Organic and nonmetallic films prevent perfect bonding due to poor adhesion between metal layer and substrate.

Rinse

(Steps 3, 5, 9): water rinse to prevent cross-contamination between tanks and carry over.

Plating

(Step 6) see electroplating process

Dragout

(Step 7): after plate metal recovery tank to prevent loss of plating solution.

Post Plating Treatment

(Step 10):  can include wax, lacquer, baking, chromate, etc.