Properties of porous aluminium

Porous aluminium provides an unique combination of material properties:
– products are permeable over the whole volume
– can be manufactured in up to large sizes and in any form
– a high strength thanks to cast structure
– controlled high volume porosity
– variable and regulated pore sizes
– homogeneous distribution of the pores over the entire volume

Porous aluminium is obtained by casting of liquid Aluminium with granulated salt and subsequently washing out ofthe salt. Depending on the size of the salt grains we receive porous aluminium with different pore sizes.

We developed seven standard grades of porous alumina with pore sizes from 0.20 mm to 4.00 mm, which are presented in the table below (click on picture to enlarge).

No. 1 No. 2 No. 3 No. 4 No. 5 No. 6 No. 7
N1_sintered_metal_foam_open_cell_structure_aluminium_foam_sinteraluminium_porous_aluminium_pore_size_200-350_mikron N2_porous_aluminium_metal_sintered_foam_heat_exchange_vacuumforms_pore_size_300-500_mikron N3_metal_foam_sinter_aluminium_porous_leight_weight_thermoforing_permeable_pore_size_400-630_mikron N4_metalfoam_aluminium_foam_sintered_for_filtration_heat_exchange_neu_material_pore_size_400-1000 N5_porous_aluminium_open_cells_permeable_hight_strength_blocks_plates_heat_exchangers_thermoforming_pore_size_630-1600_mikron N6_sinteraluminium_aluminiumfoam_porous_permeable_heat_exchangers_vacuum_pore_size_1600-3000_mikron N7_sinteraluminium_aluminiumfoam_porous_permeable_heat_exchangers_vacuum_table_pore_size_1600-4000_mikron

Properties of the porous aluminium vary depending on the pore sizes of the material, as well as from the technical parameters during the casting process. In the below table characteristics of porous Aluminium in six standard pore sizes are presented. Please consider, that some of the parameters can be changed upon customer’s request through individual selection of salt combination and variation of technical parameters while of the casting process.

Item Parameter No. 1 No. 2 No. 3 No. 4 No. 5 No. 6 No. 7
1 Pore size, mm 0,20 – 0,35 0,30 – 0,50 0,40 – 0,63 0,40 – 1,00 0,63 – 1,60 0,63 – 3,00 0,63 – 4,00
2 Filter grade, µm 40 – 50 50 – 60 70 – 90 150 – 200 300 – 400 500 – 600 600 – 700
3 Volume porosity, % 55 – 65 55 – 65 55 – 65 55 – 65 55 – 65 55 – 65 55 – 65
4 Specific surface area, m2/m3 approx. 20’000 approx. 10’000 approx. 6’500 approx. 4’000 approx. 3’000 approx. 2’500 approx. 2’200
5 Compressive strength, N/mm2 39 35 28 24 21 20 19
6 Tensile strength, N/mm2 26.0 21.0 16.4 15.3 8.3 7.6 7.2
7 Density, g/cm3 1,35 – 1,22
8 Cell structure porous_aluminium_open-cell-sintered-metall-metal-foam-alufoam
all pores are open,
d min = filter grade,
D max = pore size
9 Operating temperature, °C from -200 to +250…550
10 Melting-point, °C approx. +600
11 Hardness, HB 67 – 71
12 Thermal conductivity, W/(m*K) 30 – 50
13 Aluminium alloy AlSi7Mg
14 Cleaning, maintenance backwash, ultrasound, mechanical and chemical cleaning
15 Permeability coefficient K, m2 7,00E-12 8,50E-12 3,10E-11 7,50E-11 1,45E-10 2,25E-10 2,60E-10

111
You can use the permeability coefficient K (from the above table) for the flow rate calculation. For this the Darcy’s law will be applied:

111 К * ΔP * S
Q = ————–,
1111 μ * H

Q – flow rate, m3/sec
ΔP – pressure drop at the filter, Pa
S – filter surface, m2
μ – dynamic viscosity, Pa*sec
H – filter thickness, m

Product samples:

aluminium_porous_sintered metal_metal foam_cellular metals_products_properties_sintering_aluminium foam aluminium_porous_sintered metal_metal foam_cellular metals_products_properties_sintering_aluminium foam aluminium_porous_sintered metal_metal foam_cellular metals_products_properties_sintering_aluminium foam