Noticias

In this way, the foam structure is produced by liquid aluminum, which can be directly foamed by liquid aluminum, or the porous material can be obtained by casting foam material or tightly packed pore-making agent.

2.1. Direct blowing and foaming method
Direct blowing and foaming method: it is to add SiC, Al2O3, etc. into the molten metal, and evenly disperse to improve the melt viscosity, and then blow into the bottom of the melt gas (such as nitrogen, inert gas, etc.),after forming a large number of pores in the metal liquid ,cooling and solidification.
Features: simple equipment requirements, product voidage can be controlled, can achieve the continuous preparation of products.

2.2 foaming agent foaming method

Foaming agent foaming method is: in the aluminum melt add foaming agent stirring uniform heating foaming agent decomposition of gas, gas expansion and foaming, cooling metal foam.The foaming agents used are usually hydrogen compounds such as TH2 or ZiH2.
Features: simple equipment requirements can achieve continuous product preparation.The foaming time interval of foaming agent is short, the foaming temperature is not easy to control, the bubble distribution is not uniform.
 
2.3 seepage casting method In seepage casting, removable particles (such as NACL) are piled up in the casting mold, pressed into a blank, preheated and poured metal, and then the particles are removed to prepare a through-hole foam structure with interconnected holes.
Characteristics: the preparation process aperture parameter is controllable, the through-hole rate is high, the specific surface area is large and the cost is low, suitable for large-scale industrial production.The disadvantage is that liquid metal has a high surface tension and cannot completely wet the particles and thus fill the space between the particles.

2.4 investment casting

Investment casting method is the forming of polymer materials in liquid refractory material, fireproof material, filled with gap after the refractory material hardening heating decompose foam gasification, form a with the original foam in the shape of a 3 d frame, the metal aluminum pouring into the mold, the solidification after remove refractory can get with a 3 d mesh hole of aluminum foam materials.
Advantages: hole structure, good production repeatability, relatively stable density.But production is low and prices are high.