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What You Need to Know About Phosphor Bronze Wire
Phosphor bronze wire is a type of copper alloy wire that is composed of copper, tin, and phosphorus. The most common variety is CDA 51000 (also called Alloy C510). Typical composition includes roughly 94.8% copper, 5% tin, and 0.2% phosphorus. The addition of tin and phosphorus enhances both strength and wear resistance. The added phosphorus helps deoxidize the alloy making it easier to work with while heating, soldering, or brazing. This family of alloys is prized for toughness, moderate electrical conductivity, and resistance to corrosion, especially in challenging environments.
Common Questions:
- What are the key features of phosphor bronze wire?
- What kind of phosphor bronze wire does MWS provide?
- What are the Key Selection Factors for Choosing phosphor bronze wire?
- What are the common applications for phosphor bronze?
- Phosphor bronze by the Numbers
What are the key features of phosphor bronze wire?
Phosphor bronze wire features a blend of characteristics that give it an edge over many other copper alloys:
- High fatigue resistance: The fine grain structure of phosphor bronze makes it ideal for components subject to cyclic loading, such as springs and connectors.
- Excellent corrosion resistance: The alloy stands up well to moist, chemical, and marine environments.
- Superior wear resistance: Phosphorus enhances hardness and reduces friction, making for long-lasting parts.
- Good electrical conductivity: While not as conductive as pure copper, phosphor bronze is reliable for electrical contacts and connectors.
- Excellent elasticity: The alloy’s grain structure lends robust elasticity and spring-back for precision components
What kind of phosphor bronze wire does MWS provide?
MWS provides phosphor bronze wire (CDA 51000) per ASTM B250. MWS phosphor bronze lends itself well to several wire constructions including twisted pair or multi-conductor twisted wire (Twistite Magnet Wire®), bifilar or multiple parallel bonded wire (Multifilar® wire). In addition to multiple wire constructions of phosphor bronze, MWS can offer this wire bare, insulated, shaped, plated, bondable, laser ablated, or cut to discrete lengths.
MWS provides enameled Phosphor Bronze in ML and Formvar insulations which are commonly used for cryogenic applications. AWG sizes for enameled Phosphor Bronze are typically 28-36 AWG and other sizes are available upon request.
As with any product containing tin, MWS can provide a Conflict Minerals Reporting Template (CMRT) if requested. See Conflict Minerals Policy Statement.
The Key Selection Factors for Choosing phosphor bronze wire?
Selecting phosphor bronze for your application involves weighing several factors:
- Mechanical Strength: CDA 51000 offers ultimate tensile strengths exceeding 100 ksi for spring tempers depending on the diameter of the wire.
- Spring Properties: For spring applications, spring tempers like H08 or Spring Hard maximize elasticity and fatigue life.
- Electrical Conductivity: Phosphor bronze has lower electrical conductivity compared to pure copper (around 15% IACS), which makes it suitable for applications where both mechanical strength and some level of conductivity are required.
- Solderability: CDA 51000 delivers an optimal balance of performance and cost, and is suitable for soldering or brazing
The common applications for phosphor bronze?
Phosphor bronze is known for its versatility, serving critical roles in:
- Cryogenic Sensors: Compared to copper, phosphor bronze’s higher resistivity and lower thermal conductivity make it useful for cryogenic instrumentation to reduce heat leak
- Electrical Contacts and Connectors: Fatigue resistance and conductivity make it a standard for switches, relays, fuse clips, and other electrical hardware.
- Springs: Used for various spring-loaded mechanisms subject to repeated cycling, thanks to superb elasticity.
- Bushings and Bearings: The alloy’s low-friction and wear-resistant properties suit high-duty bushings and bearings.
- Fasteners & Industrial Components: Rapid installation and optimal performance in harsh environments.
- Marine Hardware: Excellent resistance to sea water corrosion.
Phosphor bronze by the Numbers.
Here is how phosphor bronze compares to ETP copper:
| Property | ETP Copper (CDA C11000) | Phosphor Bronze (CDA C51000) |
|---|---|---|
| Composition (%) | 99.90 Cu, 0.04 O | 94.8 Cu, 5.0 Sn, 0.2 P |
| Tensile Strength (ksi, Hard) | 55 | 110 |
| Tensile Strength (ksi, Soft) | 34 | 51 |
| Yield Strength (ksi, Hard) | 50 | 85 |
| Yield Strength (ksi, Soft) | 12 | 21 |
| Elongation (% Hard) | 5 | 5 |
| Elongation (% Soft) | 36 | 49 |
| Electrical Conductivity (% IACS) | 100 | 15 |
| Electrical Resistivity (ohms/cmf) | 10.3 | 69.1 |
| Density (lb/in³) | 0.323 | 0.32 |
| Melting Point (°C) | 1065 | 954 |
Where to learn more about Phosphor Bronze
More information about Phosphor Bronze can be found on our Copper and Copper Alloy Wire product page. If you know what you need already or have a question for our sales team, you can contact us directly.