Technical Guide for Material Selection and Surface Treatment of Micro Screws

Micro screws are widely used in digital electronics, medical devices, optical instruments and toys. Materials and surface treatments determine the strength, anti-rust performance and service life. This article summarizes common materials and processes for reference.

1. Main Materials and Application Scenarios

1. Carbon steel: Cost-effective and hard. Suitable for indoor electronics and toys. It needs plating for rust prevention and is not recommended for humid outdoor environments.

2. Stainless steel (304/316): Excellent rust and corrosion resistance. 304 stainless steel is widely used in digital products and home appliances. 316 stainless steel performs better in salt fog and acid environments, ideal for medical devices and outdoor wearables.

3. Copper alloy: Good electrical conductivity and appearance, mainly used for conductive components and high-end optical equipment, not suitable for heavy-load connections.

2. Common Surface Treatment Processes

1. Nickel/Zinc plating: Basic anti-rust treatment for carbon steel screws with low cost, widely used in civilian products.

2. Black electrophoresis: Improves wear resistance, suitable for hidden parts of electronic products.

3. Thread locking coating: Prevent screws from loosening under vibration, a standard process for wireless earbuds and smart wearable devices.

4. Passivation: For stainless steel screws. It enhances corrosion resistance without coating peeling, suitable for medical and food-grade equipment.

3. Simple Selection Suggestions

Choose carbon steel plated screws for common indoor products. Select 304/316 stainless steel for humid, outdoor and medical scenarios. Use thread-locking screws for vibrating equipment. Do not mix screws of different materials to avoid electrochemical corrosion.