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中文|English

SterlingStar Ag-01

Column：Silver Plating Additive

1. Introduction

SterlingStar Ag-01 is used in the electronics industry and for decorative electroplating. This product does not contain metal brighteners, and the plating solution exhibits stable performance.

 

2. Characteristics

lSoft and high-purity coating - After treatment with AgAuShield Plus silver protector, the plating exhibits excellent tarnish resistance and good solderability.

lSuperior electrical conductivity with low contact resistance.

lWide operating range - Even at low current density, a satisfactory brightness can be achieved.

lSuitable for rack plating and barrel plating.

lCan be plated over nickel layers, bronze, brass, and other copper substrates.

3. Materials

lMetallic silver (added in the form of potassium silver cyanide)

lPotassium cyanide

lPotassium hydroxide

lSilver brightener A

lSilver brightener B


4. Coating Characteristics

Property

Value / Performance

Purity

99.9%

Hardness

100–130 HV (Vickers)

Coating Density

105 mg/µm·dm²

Cathode Efficiency

67 mg/A·min

Time Required to Deposit 1 µm


- 1 A/dm²

1.5 minutes

- 10 A/dm²

9.5 seconds

- 100 A/dm²

0.95 seconds

 

5. Operating Conditions

 

Parameter

Type

Unit

Range

Optimal

Metallic Silver

(added as Potassium Silver Cyanide)

-

g/L

20-40

30

Potassium Cyanide

(Free)

Rack Plating

g/L

90-150

120


Barrel Plating

g/L

90-200

150

Potassium Hydroxide

-

g/L

5-10

7.5

Silver Brightener A

-

mL/L

-

20

Silver Brightener B

-

mL/L

-

10

pH

-

-

12-12.5

-

Temperature

Rack Plating

°C

20-40

25


Barrel Plating

°C

18-30

20

Current Density

Rack Plating

A/dm²

0.5-4

1


Barrel Plating

A/dm²

0.2-0.5

0.5

Anode:Cathode Ratio

Rack Plating

-

1:1-2:1

>2:1


Barrel Plating

-

1:1-2:1

>1:1

Agitation

-

-

Cathode Movement

-

Anode Bag Material

-

-

Polyester, Nylon

-

Cathode Efficiency

-

mg/A·min

-

67

Time to Deposit 1 μm at 1 A/dm²

-

sec

-

100

Time to Deposit 1 μm at 0.5 A/dm²

-

sec

-

200

Silver Consumption

-

g/A·h

-

4.0

Anode

-

-

Pure Silver Plate or Silver Beads in Titanium Basket with Anode Bag

-

 

6. Plating Solution Preparation

1. Thoroughly clean the plating tank, then fill it halfway with deionized or distilled water. Heat to 30°C, then add potassium hydroxide and potassium cyanide. Stir until completely dissolved.

 

2. Add the silver salt (potassium silver cyanide) pre-dissolved in pure water. If using silver cyanide, it can be added directly to the tank.

 

3. After all the above chemicals are fully dissolved, add Additive A and Additive B, stirring until uniformly mixed into the solution.

 

4. Heat to the appropriate operating temperature and adjust the volume with additional water.

 

Note: After Step 2, the solution must undergo activated carbon treatment to remove impurities.

 

7. Composition and Function

 

Component

Form/State

Function

Effects of Imbalance

Maintenance Notes

Silver (Ag)

Potassium silver cyanide

- Primary metal source
- Replenished via anode dissolution or direct addition

- Low Ag: Poor deposition
- Excess Ag: Unstable solution

Monitor Ag concentration; adjust via anode or salt addition

Potassium Cyanide (KCN)

Free cyanide in solution

- Complexes with Ag
- Enhances conductivity, diffusion, and anode dissolution

- Low KCN: Anode polarization, reduced brightness
- High KCN: Excessive drag-out

Higher current/temperature increases consumption; replenish regularly

Potassium Hydroxide (KOH)

Alkaline pH adjuster

- Maintains pH >12.0
- Prevents cyanide decomposition
- Aids anode dissolution

- Low pH: Cyanide breakdown
- High pH: Carbonate buildup (from CO₂)

Check pH frequently; neutralize carbonates if needed

Additive A

Brightener (consumable)

- Enhances deposit brightness

- Depletion causes dull plating

Replenish based on Amp-hours (A·h) or plating volume

Additive B

Grain refiner (drag-out loss)

- Refines crystal structure
- Improves smoothness

- Low levels reduce grain refinement

Top up due to drag-out only; no electrochemical consumption


 

8. Equipment

 

Component

Specifications

Notes

Plating Tank

PYREX, PTFE, PP, PVC, or polyacetylene materials

Must be chemically resistant to alkaline cyanide solutions

Cooling/Heating

Stainless steel, ceramic, titanium, or PTFE heating/cooling coils

Avoid corrosion-prone materials

Filtration

Continuous filtration with PP filter cartridges

Pre-treat cartridges by soaking in 80–90°C KOH (20 g/L) for 1 hour before use

Rectifier

Standard DC rectifier

No special requirements

Anode

- Silver beads
- High-purity silver plates (in anode bags)
- Stainless steel or platinum-coated titanium mesh

Anode:Cathode ratio ≥ 1:1

Agitation

- Cathode rod movement
- Mechanical agitation

Air agitation prohibited (risk of cyanide mist)

Ventilation

Mandatory fume extraction system

Required to minimize toxic mist exposure

 

9. Plating Solution Maintenance

 

Regular Analysis & Replenishment

Monitor and maintain silver (Ag) and potassium cyanide (KCN) concentrations within optimal ranges.

 

Additive Consumption Rates

Additive

Plating Type

Dosage (mL/A·h)

Brightener A

Rack Plating

0.25–1


Barrel Plating

0.25–1

Brightener B

Rack Plating

0.03–0.1


Barrel Plating

0.05–0.15

 

When using soluble silver anodes:

Brightener A: 0.5 L per 1,000 A·h.

Brightener B: Only lost through drag-out (no electrochemical consumption).

 

For Insoluble Anodes:

Periodically add silver salts (e.g., silver cyanide) to compensate for silver depletion.

Brightener A consumption increases — adjust dosing accordingly.

Supplement potassium hydroxide (KOH) to maintain pH > 12.

 

Critical Silver Replenishment Protocol:

To avoid excess free cyanide, use silver cyanide (80% Ag content) for replenishment.

Pre-dissolve in a small volume of plating solution before adding to the main tank.

 

10. Disclaimer

All recommendations and suggestions regarding our company's products in this manual are based on experiments and data we deem reliable. Since we cannot control the actual operations of other practitioners, our company cannot guarantee or be held responsible for any adverse consequences.


SterlingStar Ag-01 MSDS English v1.pdf

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