What are Gold Au Coated Contacts?
Gold Au Coated Contacts are electrical contact components made by coating a substrate (usually copper, copper alloy, nickel-based alloy, etc.) with a layer of high-purity gold (Au) or gold alloy. Using either an electroless gold plating or an electroplating process, the gold layer is evenly applied to the contact surface, improving contact performance, corrosion resistance, and electrical conductivity. Gold-plated contacts are widely used in electronic, electrical, and new energy devices requiring high reliability and low contact resistance.
Material Properties and Performance Indicators
The core advantage of Gold Plating Contacts stems from the unique physical and chemical properties of gold (Au):
1. Excellent Electrical Conductivity
Gold has a resistivity of approximately 2.44 μΩ·cm, only slightly higher than silver (1.59 μΩ·cm). It maintains extremely low contact resistance even in humid and corrosive environments.
2. Extreme Corrosion Resistance
Gold is extremely stable in air, moisture, salt spray, and various acidic environments, undergoing virtually no oxidation.
Salt Spray Test: Gold-plated layers ≥ 0.5 μm thick can pass a 48-96 hour salt spray test with no visible corrosion spots.
3. Wear Resistance and Stability
Although gold is inherently soft, alloying (such as hard gold plating with the addition of cobalt or nickel) can increase its Vickers hardness to 130-200 HV, significantly extending its service life.
4. Excellent Solderability
Au-plated contacts can be directly connected with tin soldering, silver soldering, or hot press welding, offering excellent wettability and reducing the risk of cold solder joints.
5. Relationship between Thickness and Electrical Performance
Thin gold plating (0.05-0.1 μm): Suitable for signal terminals; low cost but moderate wear resistance.
Thick gold plating (0.5-2.5 μm): Suitable for high-frequency plugging and unplugging or harsh environments, ensuring contact stability.
Production Process and Quality Control
The manufacturing process for gold-plated electrical Contacts requires extremely high precision and consistency. The key steps include:
1. Substrate Preparation
Select high-conductivity copper, copper alloys (such as brass, beryllium copper), or nickel alloys.
Mechanically polish or precision stamp the surface to ensure dimensional tolerances meet design requirements (within ±0.01 mm).
2. Surface Pretreatment
Degreasing: Removes oil and processing residue.
Pickling: Removes oxide film.
Activation: Enhances gold layer adhesion.
3. Nickel Primer
A 1-2 μm nickel layer is typically applied before gold plating to prevent diffusion between the substrate and the gold layer and maintain the gold layer's purity.
4. Gold Plating
Hard Gold Plating: For Gold Plated Relay Contacts that are frequently plugged and unplugged.
Soft Gold Plating: For Electrical Contacts Gold Plated that require soldering.
The plating thickness is precisely controlled, often using an online X-ray thickness gauge with an accuracy of ±0.01 μm.
5. Post-Processing and Testing
Salt spray testing, friction and wear testing, and contact resistance testing are performed.
Typical contact resistance requirement: ≤10 mΩ.
Core Advantages and Value
1. Stable Low Contact Resistance
Gold does not form an oxide film on the surface, maintaining stable signal transmission even under low currents. It is suitable for applications requiring extremely high signal integrity, such as 5G communications, precision measurement, and medical equipment.
2. Excellent Environmental Resistance
Even in high-temperature and high-humidity environments of 85°C and 85% humidity, the performance degradation of Gold Plating Copper Rivets is minimal, with a lifespan exceeding 10 years.
3. Adaptable to Frequent Plugging and Low Current
Thick Gold Flash Plating Contacts maintain a contact resistance change of less than 5 mΩ after 5,000 to 10,000 plugging and unplugging cycles, significantly reducing maintenance costs.
4. Reduced Maintenance and Downtime Costs
In industrial automation, rail transit, and new energy storage systems, the use of Gold Plated Bimetal Contacts can reduce downtime and repair costs caused by poor contact.
5. Improving Overall System Reliability
In high-voltage connectors for new energy vehicles and aerospace communication systems, stable contact performance directly determines system safety and continuous operation.
Typical Application Areas
1. New Energy
Electric Vehicle High-Voltage Connectors
Energy Storage System (ESS) Terminals
Photovoltaic Inverter Electrical Interfaces
2. Communications and Data Centers
Optical Module Interfaces
High-Speed Signal Transmission Connectors
5G Base Station RF Modules
3. Industry and Automation
Precision Test Fixtures
Industrial Robot Signal Ports
PLC Control System Connectors
4. Aerospace and Military
Satellite Communication Interfaces
Flight Control System Connectors
High-Reliability Gold-plated Rivets
5. Medical Equipment
High-Precision Sensor Interfaces
ECG/EEG Monitoring Equipment Terminals
Surgical Robot Control Modules
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