The Influence of Trace Elements in Aluminum Substrates on the Mechanical Properties of PS Plates

The aluminum substrate refers to the base material used in the production of PS plates (pre-sensitized plates). It is primarily made from high-purity aluminum or aluminum alloys and manufactured through processes such as rolling, annealing, and surface treatment. It features excellent mechanical properties and chemical stability and is one of the most commonly used carrier materials in the printing industry.

The aluminum alloys commonly used in printing plates include 1050, 1060, and 1070 series pure aluminum, which have aluminum contents above 99.5%. These alloys offer good plasticity and high ductility.

The content of trace elements in aluminum plates has a significant impact on their mechanical properties, such as strength, hardness, ductility, and corrosion resistance. The following outlines some common trace elements and their effects on aluminum plate performance:

1. Magnesium (Mg)

Function: Solid solution strengthening, enhances the strength and hardness of the aluminum substrate. However, excessive Mg (>1%) may reduce toughness and increase brittleness.

Impact on PS plates:

Positive: Improves wear resistance and fatigue resistance.

Negative: Excessive Mg can cause anodic oxide film embrittlement, reducing the adhesion strength of coatings.

Recommended content: 0.3%–0.8% (depending on heat treatment processes).

2. Manganese (Mn)

Function: Neutralizes the harmful effects of iron and refines the grain structure.

Impact on PS plates:

Positive: Enhances work hardening rate after rolling and improves surface uniformity.

Recommended content: 0.05%–0.2% (must be balanced with Fe content).

3. Copper (Cu)

Function: Significantly increases strength but intensifies intergranular corrosion tendencies.

Impact on PS plates:

Negative: Reduces the compactness of anodic oxide films and affects the chemical resistance of the coating.

Recommendation: Usually controlled below 0.1% (should be avoided when high corrosion resistance is required).

4. Silicon (Si)

Function: Forms hard Mg₂Si phases, enhancing hardness and wear resistance; excessive Si may precipitate coarse silicon particles.

Impact on PS plates:

Positive: Improves surface roughness, aiding coating adhesion.

Negative: Excessive Si (>0.5%) leads to local stress concentration and reduces bending resistance.

Recommended content: 0.2%–0.4% (should be combined with homogenization annealing).

5. Iron (Fe)

Function: Forms FeAl₃ phases and refines grains; excess Fe (>0.3%) can produce brittle intermetallic compounds.

Impact on PS plates:

Positive: Increases tensile strength and reduces rolling defects.

Negative: Excessive Fe leads to uneven oxide films (black spots), reducing corrosion resistance.

Recommended content: ≤0.25% (strict purity control required).