Copper and aluminum, as we all know, are two key industrial metals that have significant substitution and complementary relationships in fields such as conductivity, thermal conductivity, and mechanical properties.

This substitutability is driven by multiple factors such as cost, performance, technological development, and environmental protection needs. So, today we will talk in detail about the various origins between copper and aluminum

Firstly, let's take a look from the perspective of cost. The price of copper is about 3-4 times that of aluminum, but aluminum's lightweight (with a density of 30% of copper) can further reduce transportation and installation costs. For example, in the field of power transmission, replacing pure copper cables with aluminum core cables (such as ACSR aluminum stranded wire) can save 30% -50% of costs, but it requires an increase in cross-sectional area to compensate for the difference in conductivity

Next, let's take a look at other performance comparisons.

1、 Conductivity comparison

The conductivity of copper (100% IACS) is significantly better than that of aluminum (61%). But aluminum can partially compensate for the gap by increasing cross-sectional area or alloying (such as aluminum magnesium silicon alloy).   

2、 Comparison of Corrosion Resistance

Copper is naturally resistant to oxidation, while aluminum requires surface treatment (coating, anodizing) before it can be used in humid environments.   

3、 Comparison of mechanical strength

Copper has better ductility, while aluminum alloy can improve its tensile strength through cold processing (such as AA8000 series aluminum alloy used in automotive wiring harnesses).

4、 Comparison in Environmental Protection

We know that the carbon emissions from copper mining (about 4 tons of CO ?/ton of copper) are higher than aluminum (about 12 tons of CO ?/ton of aluminum, but only 0.5 tons of CO ?/ton of recycled aluminum).

The advantages of aluminum recycling promote its ability to replace copper in some scenarios... Next, let's talk about typical substitution scenarios and technical solutions for copper and aluminum.

Power transmission and distribution

Alternative directions: Aluminum → Copper (high cost scenario) or Copper → Aluminum (low-cost scenario)

1、 It can be applied to high-voltage transmission, such as aluminum stranded wire (ACSR) dominated by lightweight and low-cost advantages, but requires a 60% increase in cross-sectional area compared to copper wire to achieve the same current carrying capacity.   

2、 Can be applied to distribution transformers, such as replacing copper windings with aluminum windings (reducing costs by 20% -30%), but requires an increase in volume and optimization of heat dissipation design.   

In terms of technological breakthroughs, aluminum core copper plating technology (CCA) can improve surface conductivity and is used for medium and low voltage cables; Nano coated aluminum wires can reduce contact resistance (such as graphene coated aluminum wires).

Electronic and communication equipment

Alternative direction: Copper → Aluminum (in the field of high-frequency signals)

1、 Can be applied to high-frequency circuits. By utilizing the skin effect of aluminum (where high-frequency currents concentrate on the surface of conductors), copper-clad aluminum wire (CCA) replaces pure copper in RF antennas and coaxial cables.   

2、 Can be applied to integrated circuits. The chip interconnect layer attempts to replace copper with aluminum (low-cost), but needs to address the issue of electromigration (aluminum atom migration causing circuit breaks).   

But there are technical contradictions, such as copper still dominating high-end chips (processes below 7nm) due to high aluminum resistivity affecting performance.

Automobiles and New Energy

Alternative direction: Copper → Aluminum (lightweight demand)

1、 Can be applied to electric vehicle wiring harnesses. Aluminum wire reduces weight by 40%, but the reliability of terminal crimping needs to be addressed (aluminum cold creep characteristics are prone to loosening).   

2、 Can be used for battery connectors. Aluminum alloy replaces copper bars (such as CATL CTP technology) to reduce the weight of battery packs, but nickel plating is required to prevent oxidation.   

However, there are challenges such as unstable contact resistance of aluminum that may cause overheating, and Tesla Model S has been recalled due to aluminum wire connection issues.

Architecture and Home Appliances

Alternative direction: Copper → Aluminum (low-cost scenario)

1、 Can be applied to air conditioning pipelines. Aluminum instead of copper cold pipes (such as Gree's "aluminum instead of copper" technology) can reduce costs by 30%, but the difficulty of welding processes increases.   

2、 Can be used for building cables. If aluminum alloy cable (AA8030) replaces copper cable, it needs to be equipped with anti-oxidation connectors.   

But there are also controversial points, such as the risk of fires caused by oxidation of aluminum wire in the renovation of old buildings (such as aluminum wire building accidents in the 1970s in the United States).

So, in which fields are copper and aluminum irreplaceable?

Such as high-frequency and high-precision scenes. High end audio cables and medical equipment sensors must use oxygen free copper (OFC) due to the high signal attenuation rate of aluminum.

Secondly, extreme environmental applications such as deep-sea cables and spacecraft wires rely on copper's corrosion resistance and fatigue resistance, while aluminum is difficult to meet reliability requirements.

Finally, miniaturized electronic components such as chip TSV (silicon via) technology require copper plating and filling capabilities, while aluminum cannot achieve nanometer level precision.

What is the development trend of future substitution? There are three points to pay attention to!

1、 Pay attention to the rise of copper aluminum composite materials

By combining the advantages of copper aluminum laminates (power electronic heat dissipation) and copper-clad aluminum magnesium alloy wires (5G base stations), the market size is expected to reach $12 billion by 2025.

2、 Focus on the competition of recycled metals

The purity of recycled copper is difficult to maintain (requiring refining), while recycled aluminum (such as automotive scrap aluminum) can be directly melted and cast, and the proportion of aluminum replacing copper in the circular economy may increase.

3、 Pay attention to the impact of superconducting materials

If high-temperature superconducting cables are commercialized (such as rare earth barium copper oxide materials), the traditional conductive applications of copper and aluminum will face disruption.

Summary:

The essence of replacing copper and aluminum is a triangular game of performance, cost, and sustainability!   

In the short term, aluminum is accelerating its substitution for copper in the fields of electricity and automobiles, but high-end manufacturing still relies on copper.   

In the long run, copper aluminum composite materials and emerging superconducting technologies may rewrite the rules of substitution.   

But the key limiting factors include the oxidation risk of aluminum and the bottleneck of connection technology; The scarcity of copper resources and price fluctuations. Decision makers need to combine specific scenarios and conduct a full lifecycle cost analysis (including recycling value) to choose the optimal solution, rather than simply pursuing "replacing copper with aluminum" or "replacing aluminum with copper".

Article source: Internet

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