Aluminum bronze is suitable for casting and has excellent casting properties.
Casting Properties
Aluminum bronze (such as QAl9-4 and ZCuAl10Fe3) exhibits excellent fluidity and mold filling during the casting process, making it suitable for the production of large castings. Its melting point is typically between 950-1060°C, and its casting temperature range is wide (1100-1180°C).
Process Advantages
Aluminum bronze is often cast using a metal mold casting process, which produces castings with precise dimensions and a smooth surface. Post-casting heat treatment processes such as annealing at 700-750°C and quenching at 850°C can further enhance its mechanical properties (tensile strength ≥540 MPa, elongation ≥15%).
Applications
It is widely used in high-load, high-strength components such as ship propellers, mechanical bearings, bushings, and worm gears, as well as in corrosion-resistant and wear-resistant applications such as chemical equipment and power plants.
What is the corrosion resistance of aluminum bronze?
Aluminum bronze, a copper alloy with a copper matrix and aluminum as the primary alloying element, is widely used in industry for its excellent corrosion resistance. The following detailed analysis of aluminum bronze’s corrosion resistance properties is presented from various perspectives:
Basic Corrosion Resistance
Aluminum bronze’s outstanding corrosion resistance is primarily due to its unique chemical composition and surface protection mechanism:
Chemical Advantages: The aluminum content in aluminum bronze is typically between 8-11%. This aluminum element forms a dense Al₂O₃ oxide film on the surface, effectively preventing further corrosion.
Protection Mechanism: In the initial stages of corrosion, aluminum preferentially oxidizes to form a nanoscale Al₂O₃ film. Subsequently, copper ions combine with chloride ions to form a Cu₂(OH)₂Cl passivation layer. After 24 hours, a “sandwich structure” protective layer forms (outer layer of Cu₂O/Cu(OH)₂, middle layer of Al₂O₃+Fe₂O₃, and inner layer of Cu-Al intermetallic compound).
Environmental adaptability: Resistant to corrosion from the atmosphere, seawater, and most organic acids, maintaining stable performance below 250°C.
Of course, corrosion resistance varies in different environments, primarily in three environments: seawater, acidic environments, and alkaline environments.
1. Seawater
Aluminum bronze performs particularly well in seawater:
The annual corrosion rate is less than 0.05mm, far superior to ordinary brass.
It is suitable for marine engineering components such as propellers and marine valves.
The corrosion rate in a 3.5% NaCl solution can be as low as 0.008mm/year (when the Al content is 9.1% and the Fe content is 4.0%).
2. Acidic environments
It exhibits good corrosion resistance in acidic media such as dilute sulfuric acid and hydrochloric acid.
The corrosion rate in 70% nitric acid is less than 0.1mm/year.
However, it performs poorly in strong oxidizing acids (such as concentrated sulfuric acid and nitric acid).
3. Alkaline environments
It has better alkaline resistance than brass.
It performs well in low-concentration alkaline solutions.
However, strong alkaline environments may still cause corrosion.
This shows that aluminum bronze, due to its unique chemical composition and microstructure, exhibits excellent corrosion resistance in a variety of corrosive environments, making it particularly suitable for the manufacture of critical components in harsh environments such as the marine and chemical industries. If you have large-volume aluminum bronze casting needs, you can choose to cooperate with Mulan Metal. Mulan Metal has 12 years of experience in metal casting production, helping customers in more than 30 countries to complete casting production business support and has received unanimous recognition. We look forward to your cooperation consultation.
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