Bare Aluminum Foil

Definition and Basic Characteristics of Bare Aluminum Foil

Definition

Bare aluminum foil is a thin sheet of pure or alloyed aluminum without additional coatings, laminations, or surface treatments. It is widely used across various industries due to its lightweight nature, high thermal and electrical conductivity, corrosion resistance, and excellent barrier properties.

Bare Aluminum Foil:

• Made from high-purity aluminum or aluminum alloys.
• Available in different thicknesses, widths, and tempers.
• Can be used directly or further processed for specific applications.

Core Characteristics:

Classification of Bare Aluminum Foil

Bare aluminum foil can be classified based on thickness and surface state:

1. Thickness Classification

2. Surface State Classification

Common Alloy Grades and Performance Comparison of Bare Aluminum Foil

Different alloys are used in bare aluminum foil production to meet specific mechanical and chemical property requirements.

Each alloy offers a balance of strength, corrosion resistance, and formability, making them suitable for various applications.

Production Process of Bare Aluminum Foil

The manufacturing process involves precision rolling and strict quality control:

Casting and hot rolling:

• Molten aluminum (purity +99.5%) is cast into slabs.
• Slabs are hot rolled to a thickness of 2 to 6 mm.

Cold rolling:

• Multiple passes reduce the thickness to the target range (e.g. 0.006 mm).
• Lubricants (e.g. mineral oil) minimize surface defects.

Annealing:

Intermediate annealing (200-350°C) restores ductility.
Final annealing determines tempering:

• O state: soft, fully annealed (for deep drawing).
• H18 state: hard, high tensile strength.

Slitting and inspection:

• Precise slitting to the required width (e.g. 200–1,500 mm).
• Check for surface pinholes (≤50/m² for 10 μm foil).

Core Application Areas of Bare Aluminum Foil

Bare aluminum foil is used in a variety of industries due to its lightweight nature, high conductivity, and barrier properties.

1. Electrical Industry

• Transformer winding: High-purity aluminum foils (1050, 1060) are used in transformer windings for energy-efficient performance.
• Battery foil: Used in lithium-ion batteries for enhanced conductivity and performance.

2. Packaging Industry

• Food packaging: Bare aluminum foil provides an excellent barrier to moisture, light, and bacteria.
  • Chocolate packaging: Barrier to moisture and odors (0.009 mm foil).
  • Retort pouch: Withstands steam sterilization at 121°C.
• Pharmaceutical packaging: Used in blister packs to protect medicines from environmental exposure.
  • Blister Packaging (PTP): Protects tablets from moisture and contamination.
  • Vaccine Packaging: Ultra-barrier foil for cold chain logistics

3. HVAC and Insulation

• Duct insulation: Aluminum foil is used to cover HVAC ducts to enhance thermal efficiency.
• Building insulation: Reflective aluminum foil is used in roofing applications to prevent heat transfer.

4. Automotive and Aerospace

• Heat shields: Used in engine compartments to protect components from excessive heat.
• Lightweight structures: Aluminum foil is used in aerospace applications to reduce weight without compromising strength.

Performance Testing and Quality Control

Quality control is critical to ensure that bare aluminum foil meets industry standards.

Quality Control Measures:

• Raw Material Purity: Spectrometer verified Aluminum content ≥ 99.5%.
• Cleanroom Production: ISO Class 6 environment for ultra-thin foils.

Industry Standards and Certifications

Bare aluminum foil must comply with various international standards to ensure reliability and safety.

Certifications such as ISO 9001, RoHS, and SGS further ensure quality compliance for manufacturers.

Summary

Bare aluminum foil is a versatile material with applications across multiple industries, including electrical, packaging, HVAC, and automotive sectors. With various alloy grades, surface finishes, and performance characteristics, it provides exceptional conductivity, corrosion resistance, and flexibility. Strict quality control measures and adherence to industry standards ensure the foil meets high-performance requirements for critical applications.

By understanding the classification, production process, and key applications, industries can effectively utilize bare aluminum foil for optimal performance and efficiency.