What Is 1050 Alloy Aluminum Foil?
1050 alloy aluminum foil belongs to the 1xxx series of wrought aluminum alloys, defined by a minimum aluminum content of 99.5%. Because it contains almost no deliberate alloying additions, the material preserves the inherent qualities of pure aluminum: high electrical and thermal conductivity, excellent ductility, and good resistance to atmospheric corrosion and mild chemicals. These properties make 1050 foil a standard choice for lithium-ion battery cathode current collectors, electrolytic capacitors, heat exchangers, and food-contact packaging.
The alloy is identified under EN 573-3, and foil and strip products are commonly supplied in accordance with ASTM B209, EN 546, or GB/T 3880. The last two digits of the designation indicate the minimum aluminum purity: for 1050, the minimum is 99.50%. Iron and silicon are the main trace elements and are normally controlled below 0.40% each so that they do not degrade electrical performance.
Key Properties of 1050 Foil
High purity directly translates into practical performance. The foil typically delivers an electrical conductivity of 60% IACS or higher and a thermal conductivity in the region of 220 W/(m·K), which supports efficient heat spreading in electronic and thermal-management assemblies. In the soft annealed O temper, elongation is typically 25% or more, allowing deep drawing, bending and high-speed winding without cracking. Even in the fully work-hardened H18 temper, the foil retains enough ductility for slitting and electrode winding operations.
Chemically, 1050 foil forms a dense, self-limiting oxide layer that resists moisture, mild acids and common electrolytes. The material is non-toxic and free of heavy alloying metals, which is why it is accepted for direct and indirect food contact in many markets. For battery applications, a clean, low-oil surface is critical; foil destined for electrode coating is processed and cleaned to keep residual rolling oil extremely low so that electrolyte compatibility is not compromised.
Temper Selection and Dimensional Control
1050 foil is available in a range of tempers to match the manufacturing method of the end product. The O temper is fully annealed and suited to deep forming, embossing and container production. Work-hardened tempers such as H12, H14, H16 and H18 offer progressively higher strength, with H18 providing maximum stiffness for applications where the foil must resist deformation during handling and assembly.
Typical foil gauges range from 0.008 mm to 0.2 mm. Thickness tolerance for very thin gauges is commonly held within about 4%, and width tolerance is controlled to roughly 0.3 mm for narrow coils, which supports automated coating and slitting lines. Surface roughness is typically maintained between 0.15 and 0.4 μm so that electrode slurries and adhesives spread evenly, and surface wetting tension is kept at or above 31 mN/m as an indicator of cleanliness.
Applications of 1050 Alloy Aluminum Foil
Battery industry: H18 foil in gauges around 0.01 to 0.02 mm is widely used as cathode current collector material in consumer electronics, electric vehicle and energy-storage batteries. High conductivity reduces internal resistance, while tight dimensional control improves coating uniformity.
Capacitors: O and H12 tempers in the 0.015 to 0.05 mm range are used for anode and cathode foils of electrolytic capacitors, where surface purity and smoothness support consistent oxide film formation.
Packaging: O temper foil from 0.02 to 0.1 mm is used for flexible food packaging, foil containers and medical wrapping, taking advantage of the material's non-toxicity and barrier performance against moisture, oxygen and light.
Thermal management: H16 and H18 foils are applied as fins and liners in heat exchangers, HVAC units and electronics cooling, where the high thermal conductivity accelerates heat transfer.
Decorative and general industrial use: the foil is also used for gift wrap, labels, insulation layers, electrolytic cell components and thin-walled casings where smoothness and corrosion resistance are valued.
Handling and Fabrication Guidance
Store coils in a clean, dry environment with relative humidity kept below about 45% to limit surface oxidation. Use non-abrasive lifting equipment and keep protective film in place until fabrication. For slitting, use sharp blades and controlled tension so that ultra-thin gauges are not stretched or burred. Before coating, etching or lamination, confirm that the surface is free of oil and contaminants, and dry thoroughly after any cleaning step. In forming operations, allow for the temper: O temper foil can be bent to very tight radii, while H18 foil requires larger bend radii to avoid edge cracking.
FAQ
Q1: What does the number 1050 mean in the alloy designation?
In the 1xxx series, the last two digits indicate the minimum aluminum content. For 1050, the minimum purity is 99.50% aluminum.
Q2: Which temper is best for battery current collector foil?
H18 or H14 tempers are commonly selected. H18 provides maximum stiffness for high-speed electrode winding, while H14 offers a balance between strength and handling behavior.
Q3: Is 1050 foil safe for food contact?
Yes. 1050 foil is non-toxic and free of heavy alloying elements, and it is accepted for food-contact use in many markets when supplied to the applicable food-grade requirements.
Q4: What thickness range is available for 1050 foil?
Finished gauges typically range from 0.008 mm to 0.2 mm, with thinner gauges used in capacitors and batteries and thicker gauges in packaging and thermal applications.
Q5: Why is surface cleanliness important for 1050 foil?
Residual rolling oil can contaminate battery electrolytes or weaken coating adhesion. Surface wetting tension is therefore measured to verify that the foil is clean enough for subsequent processing.
Q6: How does 1050 compare with alloyed foils in conductivity?
Because 1050 contains almost no alloying elements, its electrical conductivity is higher than that of most alloyed foils, which makes it the preferred grade where conductivity is the primary requirement.