Beryllium copper, also known as beryllium bronze, is revered as the “King of Elasticity” among copper alloys. Through solution aging heat treatment, beryllium copper achieves exceptional strength and conductivity. After heat treatment, high-strength beryllium copper alloy not only exhibits high strength and hardness but also offers excellent wear resistance, corrosion resistance, and superior casting performance. As a result, beryllium copper alloy is extensively used in manufacturing various molds, explosion-proof safety tools, and wear-resistant components such as cams, gears, worm gears, and bearings, making it a vital material in many industrial applications.
However, during maritime export, beryllium copper alloy is highly susceptible to corrosion from seawater salts and high humidity, leading to significant losses. This article focuses on the surface treatment processes of beryllium copper alloy in explosion-proof tools, aiming to minimize corrosion during maritime export.
Beryllium copper master alloy, referred to as beryllium copper alloy, is a precipitation hardening alloy with beryllium as the primary additive. After aging hardening treatment, beryllium copper alloy can achieve strength and hardness comparable to alloy steel, while also possessing the unique property of not sparking under severe impact. This makes it the ideal material for manufacturing safety explosion-proof and fireproof tools.
At room temperature, beryllium copper alloy exhibits a bright and durable color, making it a popular choice for tools and decorative items. However, in humid environments, copper tends to discolor, leading to product defects and export challenges. Therefore, surface treatment of beryllium copper alloy is necessary to reduce or prevent corrosion during maritime transport. Common surface treatments include coating, polishing, degreasing, rust removal, and passivation.
Applications of Beryllium Copper Alloy
- Electrical and Electronic Components: Beryllium copper alloy is extensively used in electrical and electronic components, especially in springs, connectors, switches, and relays. It is also widely used in computer connectors, fiber optic communication devices, integrated circuit board sockets, and automotive components.
- Switch Manufacturing: In 2004, the global switch market was projected to reach $4.1 billion, growing at an annual rate of 3.8% from $3.4 billion in 1999. The U.S. market accounted for one-third of the global electronic circuit mechanical switch shipments.
- Automotive Industry: Beryllium copper strip is a key material for automotive electronic components, primarily used in engine compartment parts such as engine control systems, where operating temperatures are high, and vibrations are intense. The use of beryllium copper in automotive electronics is increasing in North America, Europe, Japan, and South Korea, driven by the demand for new vehicle features.
- Mechanical Equipment: Due to its excellent properties, such as high temperature and pressure resistance, non-magnetic nature, corrosion resistance, high elasticity, fatigue resistance, and high strength, beryllium copper alloy is widely used in various mechanical equipment fields.
Surface Treatment Methods for Beryllium Copper Alloy
- Electrolytic Degreasing: Electrolytic degreasing involves placing the workpiece on the cathode or anode for electrolysis to remove oil stains. It is more efficient and produces better quality results than chemical degreasing, often serving as the final degreasing step before plating.
- Polishing: The higher the surface finish of the workpiece, the better the adhesion of the coating film and the better the corrosion resistance. Therefore, mechanical polishing is typically performed before coating to enhance the quality of the surface plating.
- Rust Removal: After grinding and degreasing, some parts of the workpiece may still have rust spots or be in a passivated state. Therefore, activation treatment is required before plating. Common etching agents include sulfuric acid and hydrochloric acid. In this study, a bright acid pickling method was used, combining nitric acid, sulfuric acid, and hydrochloric acid. Since beryllium copper does not react with hydrochloric acid, hydrochloric acid alone cannot be used for rust removal.