Physical and Chemical Properties

Physical Properties

Appearance:
It typically presents a silvery-white metallic color with a smooth surface and high gloss. Different surface effects can be achieved through various surface treatment processes, such as anodizing, polishing, or brushing

Density:
The density of aluminum rods is relatively low, generally around 2.70 g/cm³ , which is about one-third the density of steel. This lightweight property makes aluminum highly desirable in applications where weight reduction is critical

Melting Point:
The melting point of aluminum is relatively low compared to steel, typically around 660°C . This lower melting point facilitates casting and forming processes but limits its use in high-temperature environments

Coefficient of Thermal Expansion:
The coefficient of thermal expansion is moderate, approximately 23.1 × 10⁻⁶/°C at room temperature. This feature allows aluminum to expand and contract significantly with temperature changes, requiring careful consideration in precision applications

Thermal Conductivity:
Aluminum has excellent thermal conductivity, with a thermal conductivity coefficient of approximately 205-250 W/(m·K) . This makes it ideal for heat dissipation applications, such as heat sinks and radiators

Electrical Conductivity:
Aluminum exhibits good electrical conductivity, about 61% of that of copper (approximately 37.7 × 10⁶ S/m ). While not as conductive as copper, its lighter weight and lower cost make it a popular choice for electrical transmission lines and wiring

Chemical Properties

Corrosion Resistance:
Aluminum has excellent corrosion resistance due to the formation of a thin, dense oxide layer on its surface. This natural oxide layer protects the metal from further oxidation and environmental degradation. For example, aluminum performs well in atmospheric, freshwater, and mildly acidic environments. However, in highly alkaline or chloride-rich environments, the oxide layer may degrade, leading to pitting corrosion

Antioxidation:
Aluminum has good oxidation resistance at room temperature due to its self-passivating oxide layer. At elevated temperatures, however, aluminum can oxidize more rapidly, especially above 500°C , forming aluminum oxide (Al₂O₃), which can affect its mechanical properties

Chemical Stability:
Aluminum exhibits high chemical stability in most environments and is resistant to many chemicals, including weak acids and alkalis. However, it reacts strongly with strong acids (e.g., hydrochloric acid) and alkalis (e.g., sodium hydroxide), which can dissolve the oxide layer and corrode the metal

Passivation:
The natural oxide layer on aluminum provides passivation, enhancing its corrosion and oxidation resistance. Artificial passivation can be achieved through processes like anodizing, which thickens the oxide layer and improves durability. Anodizing involves immersing the aluminum rod in an electrolytic solution and applying an electric current to form a thicker, more protective oxide layer

Applications

Aluminum rods are widely used in various fields due to their lightweight, corrosion resistance, and good processing performance. In the aerospace industry, they are used to manufacture structural components and fasteners, leveraging their high strength-to-weight ratio. In the construction industry, aluminum rods are commonly used for window frames, railings, and decorative elements due to their aesthetic appeal and durability. In the automotive industry, they are used to produce lightweight parts, improving fuel efficiency. Additionally, aluminum rods are indispensable in the electrical industry, where they are used for power transmission lines, heat sinks, and electronic housings. Their adaptability to complex working environments makes them suitable for applications in chemical equipment, food processing machinery, and marine structures