What is aluminum foam
Brief introduction of aluminum foam
Aluminum foam is made by adding additives to pure aluminum or aluminum alloy, and it is made by foaming process, and it has the characteristics of metal and bubbles at the same time. It has both the lightweight properties of porous materials and the excellent mechanical properties and thermal, electrical and other physical properties of metal materials.
As a new type of lightweight porous metal material, aluminum foam has very broad application prospects in the fields of construction, transportation, machinery, electronics, communication and military industry, and is an engineering material with great development potential.
Structural characteristics of aluminum foam:
1.Larger aperture 0.3-7mm;
2.High and controllable porosity: 63%-90%;
3.The specific surface area is 10-45cm2/cm3;
4.Diversified pore structure: closed-cell, through-cell and micro-through-cell aluminum foam;
5.The composition and pore structure of the metal skeleton are controllable and can be adapted to different needs.
The performance characteristics of foam aluminum
Development history of aluminum foam
Humans have discovered metals for 9,000 years, manufacturing aluminum alloys for 200 years, and developing foam materials for less than 100 years. In contrast, aluminum foam has been around since the late 1950s and less than 60 years ago. It is a new type of material.
Foam aluminum classification
According to the difference of its internal pore structure, porous metal foam can be divided into through-cell and closed-cell.
1.The preparation methods of closed-cell metal foam include melt foaming method, powder metallurgy method, and electrocoating method.
2.The preparation methods of through-hole metal foam include investment casting, complex mold percolation casting, deposition method metal powder or fiber sintering method, etc.
Foam aluminum preparation process
Among the many preparation methods of foamed aluminum, the commonly used technologies in industrial application are melt blowing foaming method, melt adding foaming agent method, and powder metallurgy foaming method. They are all based on metal melts, which prevent the gas from escaping by increasing the viscosity of molten aluminum, and the aluminum foams produced are also closed-cell structures.
Features: The porosity is more than 90%, the pore size is large, the pore type is polyhedron, the foam has good toughness, and the compressive yield stress is small. It is suitable for anti-collision structural materials.
Features: Controllable pore size, uniform foam, porosity of more than 80%, nearly spherical pore shape, suitable for sound absorption and shock absorption materials.
Features: It is mainly used to produce various complex shapes of near-net-shaped aluminum foam workpieces; compared with melt foaming, the production cost is high, and the size of the obtained aluminum foam is limited.
Aluminum foam industry chain structure
The upstream of the foamed aluminum industry chain is the raw materials such as foaming agent, aluminum, silicon carbide, alumina, etc., the midstream is the production and processing of foamed aluminum products, such as foamed aluminum panels, sandwich panels, foamed aluminum special-shaped workpieces, etc., and the downstream is the production and processing of foamed aluminum products. kinds of applications.
The key raw material of foam aluminum-foaming agent
The melt foaming method is the first choice for large-scale production due to its low cost and simple equipment.
The melt foaming method currently generally uses TiH2 and ZrH2 foaming agents.
The correct selection and use of blowing agents is the core and key of the two common industrial processing methods, and determines the characteristics of the final product to a large extent.
Therefore, the development of foaming agents, especially high-efficiency and low-cost foaming agents, is the biggest bottleneck problem encountered in the industrialization development of foamed aluminum materials. To some extent, the success or failure of foaming agents is related to foamed aluminum materials.
Analysis of the application field of foam aluminum
Aluminum foam is mainly used as sound absorption and sound insulation materials, and has been widely used in rail transportation, aerospace, military, automotive, green building chemicals and telecommunications.