Preparation And Heat Dissipation Performance Of Through-hole Metallic Foams Based On The Space Holder Method

There are many methods for preparing foam metal,such as melt foaming method,percolation method,powder metallurgy method,etc.,but for melt foaming method and percolation method,it is difficult to prepare foam metal with high melting point,and it also has certain risks..Occupation method is a kind of powder metallurgy method.Using it to prepare foam metal can avoid the process of metal melting and greatly reduce the risk of high melting point foam metal preparation.Na2S2O3·5H2O is a new type of space occupant that can be reshaped after melting in a water bath at 80 °C,first used by Sun Leilei et al.At present,research on this space occupant is still lacking.In this paper,rod-shaped Na₂S₂O₃·5H₂O was used as raw material to prepare 1mm,2mm,3mm,4mm spherical spacer particles and hexagonal gridshaped spacer particles,and a variety of metal foams（foamed aluminum-zinc alloy,foamed Aluminum,high melting point copper foam）,the pore structure and metallographic structure of foam metal were observed and characterized,and the heat dissipation performance of foam aluminum and copper foam was tested and analyzed.1)A foamed aluminum-zinc alloy with a zinc content of 20% to 45% was prepared by using spherical spacer particles with a diameter of 2 mm.There is a high degree of uniformity,and the zinc particles are evenly distributed in the metallographic phase of the foamed aluminum-zinc alloy.It shows that the foamed aluminum-zinc alloy prepared by using Na2S2O3·5H2O as space holder has controllable pore structure size and shape,and the alloy composition is uniform.2)Using 1mm,2mm,3mm,4mm spherical spacer particles and hexagonal grid spacer particles,spherical cell aluminum foam and composite cell aluminum foam with high porosity were successfully prepared.From the observation of the chemical map and metallographic phase,it can be found that the pore structure of the spherical pore and the composite pore aluminum foam is controllable and the sintering is good.The spherical cell aluminum foam contains a large number of intercellular communication windows,and the composite cell aluminum foam contains hexagonal through holes with a diameter of 3mm.3)Using 1mm,2mm,3mm,4mm spherical spacer particles and hexagonal grid spacer particles,the foamed aluminum and copper foams with spherical pore structure and composite pore structure with a porosity of about 70% were successfully prepared.,and observed the metallographic phase of foamed copper,and tested and analyzed the heat dissipation performance of foamed aluminum and foamed copper.By observing the metallographic phase of the copper foam,it can be found that the copper foam is well sintered.By analyzing the heat dissipation performance of foam metal,it is found that both spherical cell foam metal and composite cell foam metal have good heat dissipation performance.Among them,the composite cell foam metal saves raw materials,and the heat dissipation performance is obviously better than that of the spherical cell foam metal.