Pure Zinc is a bluish-silver metal known for its excellent corrosion resistance, low melting point, and superior galvanizing properties. It is one of the most widely used base metals in the world, especially in protecting steel from rust.
Zinc naturally forms a protective oxide and carbonate layer, making it highly durable even in harsh environments.
With good castability and recyclability, pure zinc is a key material in construction, automotive, electrical, and chemical industries.
Chemical Composition
| Element | Typical Content |
|---|---|
| Zinc (Zn) | 99.9% – 99.995% |
| Lead (Pb) | ≤ 0.003% |
| Iron (Fe) | ≤ 0.002% |
| Cadmium (Cd) | ≤ 0.002% |
| Copper (Cu) | ≤ 0.001% |
| Aluminum (Al) | Trace |
Key Mechanical Properties
Pure zinc is not a high-strength metal, but it has unique mechanical behavior valuable for specific uses.
| Property | Typical Value |
|---|---|
| Tensile Strength | 100–150 MPa |
| Yield Strength | ~30–50 MPa |
| Elongation | 5–30% (temperature dependent) |
| Hardness | ~30–40 HB |
| Modulus of Elasticity | ~108 GPa |
| Creep Resistance | Low at room temperature |
Mechanical Behavior Notes
Zinc is brittle at room temperature but becomes ductile between 100–150°C
Shows excellent formability at elevated temperatures
Poor fatigue resistance compared to steels or bronzes
Physical Properties
| Property | Value |
|---|---|
| Density | 7.13 g/cm³ |
| Melting Point | 419.5°C |
| Boiling Point | 907°C |
| Thermal Conductivity | ~116 W/m·K |
| Electrical Conductivity | ~28% IACS |
| Coefficient of Thermal Expansion | 30.2 µm/m·°C |
| Crystal Structure | Hexagonal Close-Packed (HCP) |
| Color | Bluish-silver metallic |
Strengthening & Metallurgical Behaviour
Pure zinc has a hexagonal close-packed (HCP) lattice
Limited slip systems → low ductility at room temperature
Becomes highly formable when thermally activated
Pure zinc cannot be heat-treated like steel or aluminum alloys.
Strength improvement occurs through:
Grain size control during solidification
Work hardening (limited effect)
Alloying (primary method → brass, Zamak, zinc-aluminum alloys)
For structural or load-bearing needs, zinc is almost always used as an alloy, not in pure form.
Key Characteristics
1. Exceptional Corrosion Resistance
Forms a stable zinc oxide / zinc carbonate protective layer
Provides sacrificial (cathodic) protection to steel
Corrodes preferentially, protecting base metals
2. Sacrificial Protection Behavior
Zinc is more electrochemically active than iron
Continues protecting steel even if coating is damaged
3. Low Melting Point
Enables energy-efficient casting and refining
Ideal for coating and thermal spraying applications
4. Chemical Reactivity
Reacts readily with acids and alkalis
Useful in chemical synthesis and industrial reagents
Refining & Processing Properties
Extracted primarily from zinc sulfide ores (sphalerite)
Produced via:
Electrolytic refining (highest purity)
Imperial Smelting Process
Electrolysis yields 99.995% pure zinc
Processing Characteristics
Excellent castability
Low viscosity in molten state
Easily rolled into sheets or foils at elevated temperature
Not suitable for welding in pure form
Surface Treatment Compatibility
Easily plated
Compatible with galvanizing, thermal spraying, and powder coating
Available Forms
Zinc ingots (SHG / Prime Western grade)
Zinc sheets & plates
Zinc rods & bars
Zinc wire
Zinc powder & granules
Zinc anodes
Zinc foil
Zinc oxide & zinc salts (processed forms)
Applications of Pure Zinc
1. Corrosion Protection
Hot-dip galvanizing
Electro-galvanizing
Sacrificial anodes for ships, pipelines, storage tanks, offshore structures
2. Alloy Production
Brass (Cu-Zn)
Zamak alloys
Zinc-aluminum die-casting alloys
3. Chemical Industry
Zinc oxide
Zinc sulfate
Rubber, ceramics, paints, fertilisers
Pharmaceutical intermediates
4. Electrical & Energy
Batteries (zinc-carbon, alkaline, zinc-air)
Grounding and cathodic protection systems
5. Construction & Architecture
Roofing sheets
Cladding
Rainwater systems
Decorative architectural elements
Advantages of Pure Zinc
✔ Outstanding corrosion resistance
✔ Sacrificial protection capability
✔ Low processing energy requirement
✔ Excellent recyclability (nearly 100%)
✔ Cost-effective compared to many non-ferrous metals
✔ Environmentally sustainable coating metal
Limitations
❌ Low mechanical strength
❌ Poor high-temperature strength
❌ Brittle at room temperature
❌ Not suitable for heavy structural applications
Why Choose Pure Zinc?
Pure zinc is chosen when the primary engineering requirement is protection rather than strength.
Industries select pure zinc because it:
Extends the life of steel by decades
Reduces maintenance and replacement costs
Performs reliably in harsh environments
Is easy to process and recycle
Serves as a foundational metal for high-performance alloys
Pure zinc is a strategic industrial metal rather than a structural one. Its unmatched corrosion protection, sacrificial behavior, low melting point, and refining efficiency make it indispensable across construction, infrastructure, energy, chemical, and manufacturing industries. While mechanically soft, zinc’s true value lies in protecting, coating, alloying, and enabling long service life of other metals.