Lead–Arsenic alloys, designated UNS L50300–L50399, are special-purpose lead alloys developed to enhance hardness, creep resistance, and dimensional stability compared to pure lead—particularly for electrochemical and battery applications.
Very small additions of arsenic produce disproportionately large improvements in mechanical stability, grain refinement, and surface behavior.
Microstructure & Metallurgical Behavior
Crystal Structure: FCC lead matrix
Microstructure:
Lead matrix with finely dispersed Pb–As intermetallic phases
| Strengthening Mechanism | Effect |
|---|---|
| Solid-solution strengthening | Limited hardness increase |
| Intermetallic dispersion | Improved creep resistance |
| Aging response | Mild age hardening |
| Recrystallization | Slower than pure lead |
Metallurgical Insight:
Arsenic acts as a grain refiner and hardener, significantly improving dimensional
stability even at very low concentrations.
Corrosion & Electrochemical Behavior
Lead–arsenic alloys offer good resistance in sulfuric acid environments and outperform pure lead in battery service conditions.
✔ Reduced electrode growth and shedding
✔ More stable passive film formation
✔ Improved grid adhesion and cycle life
❌ Inferior corrosion resistance vs chemical-grade pure lead
Fabrication, Processing & Refining
| Operation | Behavior |
|---|---|
| Casting | Excellent castability, fine grain |
| Forming | Less ductile than pure lead |
| Machining | Rarely performed (smearing) |
| Joining | Soldering and lead burning possible |
| Refining | Controlled alloying required |
⚠ Proper fume control is mandatory due to arsenic toxicity.
Available Forms
Battery grids
Ingots
Sheets and strips
Extruded profiles
Specialty castings
Key Characteristics
✔ Increased hardness vs pure lead
✔ Improved creep resistance
✔ Fine-grain microstructure
✔ Better dimensional stability
✔ Good acid resistance
Applications
Battery Industry
Lead-acid battery grids
Traction and stationary batteries
Specialized battery plates
Electrical & Electrochemical
Electrodes
Current collectors
Industrial
Wear-resistant lead components
Specialized cast parts
Advantages of Lead–Arsenic Alloys
✔ Improved mechanical stability
✔ Better battery cycle life
✔ Reduced deformation under load
✔ Good corrosion resistance in acid
✔ Superior castability vs pure lead
Why Choose Lead–Arsenic (L50300 – L50399)?
Choose lead–arsenic alloys when battery grid rigidity, moderate strength improvement, minimized antimony content, and stable electrochemical performance are required.
Engineering Summary:
Lead–arsenic alloys provide a controlled strength and stability upgrade over pure
lead, particularly valuable in battery grid and electrochemical applications,
with use limited by strict health and environmental regulations.