315T Potassium Sulfide Resistant Gold & Silver Antitarnish – China Suppliers & Factory Direct Export
Product Brief
Core Product Advantages
1. Industry-Leading Potassium Sulfide Resistance
Conventional silver anti-tarnish agents turn black within 30 seconds to 3 minutes in 5% K2S solution, while 315T delivers superior anti-sulfur performance. At 25°C room temperature, silver coatings stay discoloration-free for 5–10 minutes (longer protection with thicker silver plating). It effectively blocks sulfur ion erosion from air, packaging materials and harsh industrial environments to eliminate spotting and blackening.
2. High Temperature Anti-Tarnish Property Compatible with SMT Reflow Soldering
The protective film features stable high-temperature resistance. Silver-plated workpieces treated with 315T retain bright metallic luster after 10 minutes baking at 280°C without yellowing, blackening or dullness. It fully adapts to post-processes such as SMT reflow soldering and high-temperature assembly, avoiding mass product scrapping caused by high-temperature discoloration.
3. Long-Lasting Anti-Corrosion Protection for Gold Plating
It isolates moisture and corrosive media in the air efficiently. Gold-plated workpieces treated with 315T pass 72-hour neutral salt spray test without corrosion, spots or fading, extending service life greatly for gold products used in humid, coastal and corrosive working conditions.
4. Zero Impact on Conductivity & Solderability for Precision Components
The ultra-thin transparent film carries no insulating barrier. It will not raise contact resistance of precision contacts, nor damage welding performance or signal transmission stability. It fully meets conductivity and soldering requirements of high-end precision electronic components, eliminating cold joints and signal drift issues.
Wide Application Industries & Workpieces
1. Silver-Plated Connectors for New Energy & Communication
Suitable for copper substrates pre-nickel plated + bright silver-plated automotive connectors, signal terminals and communication conductive components. It prevents silver layer blackening during long-term storage and outdoor service to guarantee stable conductive performance.
2. Silver Contacts for Precision Relays & Switches
Designed for thin silver-plated moving/static contacts and switch shrapnel. It enhances anti-tarnish capacity of thin silver coatings, prevents contact resistance drift and ensures stable, sensitive electrical signal transmission.
3. High-End Silver Jewelry & Decorative Crafts
Compatible with 925 silver ornaments, electroplated silver artworks and metal decorative parts. It blocks sulfide from rubber packaging and ambient air to avoid spotted blackening, maintains long-term mirror brightness and reduces after-sales return rates.
4. Gold & Silver Pads on PCB Circuit Boards
Specially formulated for anti-corrosion and anti-tarnish protection of PCB gold-plated and partially silver-plated pads. It solves gold pitting corrosion in humid environments while preserving excellent solderability to reject welding failure and scrap.
5. High-Temperature Resistant Silver-Plated RF Components
Ideal for thick silver-plated RF cavities, antenna assemblies and industrial parts operating under high-temperature conditions. It satisfies dual protection demands of sulfur resistance and high temperature resistance for complex harsh industrial environments.
Solution Composition & Operating Parameters
| Parameter | Working Range | Optimum Condition |
|---|---|---|
| 315T Concentration | 30 - 80 ml/L | 50 ml/L |
| Operating Temperature | 45 - 50℃ | -- |
| pH Value | -- | 7.0 |
| Soaking Time | Over 5 minutes | -- |
Complete Process Flow:
Immerse fully cleaned workpieces in diluted 315T working solution for about 5 minutes. Workpieces can be wet or dry before dipping, but thorough cleaning is mandatory.
Take out dipped workpieces and rinse in room-temperature clean water for 0.5–1 minute. Avoid over-rinsing. If low water temperature causes poor surface appearance, slightly heat the rinse water to improve finish.
Drain or spin dry cleaned parts, spread out on clean racks, then blow-dry or oven-dry below 65℃.
315T can also be used with electrolysis to achieve superior performance. Stainless steel or titanium mesh can be used as anode, with voltage set at 2–3V.
Product Performance Test Data
- Silver Plating K2S Resistance Test: No discoloration for 5–10 minutes in 5% potassium sulfide solution at 25°C
- High Temperature Resistance Test: No yellowing or blackening after 10 minutes baking at 280°C
- Gold Plating Salt Spray Test: No corrosion or spots after 72-hour neutral salt spray test
- Function Compatibility Test: No negative impact on workpiece conductivity, contact resistance or solderability
Storage Instructions
Store the product in a clean, dry warehouse with ambient temperature maintained between 5℃ and 35℃. Avoid direct sunlight exposure. Use within the valid shelf life for optimal performance.
Conventional silver anti-tarnish agents turn black within 30 seconds to 3 minutes in 5% K2S solution, while 315T delivers superior anti-sulfur performance. At 25°C room temperature, silver coatings stay discoloration-free for 5–10 minutes (longer protection with thicker silver plating). It effectively blocks sulfur ion erosion from air, packaging materials and harsh industrial environments to eliminate spotting and blackening.
Frequently Asked Questions (FAQ)
315T is a high-performance, anti-tarnish chemical designed specifically for electroplated gold and silver layers. It is widely used in electronic connectors, precision jewelry, PCB electroplating, and other industries to prevent oxidation and corrosion.
For silver coatings, 315T keeps the surface discoloration-free for 5–10 minutes under a 5% potassium sulfide (K2S) test at 25°C. The duration of protection is positively correlated with the thickness of the silver layer.
Yes. Silver-plated workpieces treated with 315T retain their bright metallic luster even after 10 minutes of baking at 280°C, without yellowing, blackening, or dullness. This makes it fully compatible with SMT reflow soldering.
No. The ultra-thin transparent film carries no insulating barrier. It does not raise contact resistance or damage the welding performance and signal transmission stability of precision components.
The recommended concentration is 30 - 80 ml/L (optimum: 50 ml/L), operating at a temperature of 45 - 50°C, a pH value of 7.0, and a soaking time of over 5 minutes.
It should be stored in a clean, dry warehouse at ambient temperatures between 5°C and 35°C. Avoid direct sunlight and use within its valid shelf life for optimal performance.