Fabrication and properties of hollow powder porous structures

• Published in: Materials letters 2004, Vol.58 (1), p.115-118
• Main Authors: El-Badry, S.A., El-Geassy, A.A., Moustafa, S.F.
• Format: Article
• Language: English
• Subjects: Fabrication; Hollow powder; Porous
• ISSN: 0167-577X; 1873-4979
• DOI: 10.1016/S0167-577X(03)00426-9

Low-cost steel porous structure materials have been prepared from hollow sphere mill-scale powders by using a simple method. Hollow spheres of mill-scale material were fabricated by coating polystyrene spheres, using pelletizer disc. The coated powders were mixed with 1 wt.% inorganic binder diluted in 4 wt.% water, and then were uniaxially pressed at 0, 100, 200 and 400 MPa in a die to produce rectangular shape compacts (30×15×15 mm), calcined at 550 °C for 30 min (to burn off the organic materials). After calcination, the compacts were then sintered in hydrogen atmosphere for 40 min at 1150 °C. The resulted steel porous materials have different relative densities varied from 32.3% to 50.89%, depending upon the previous compaction pressing before sintering. It is noted that the relative density increased with the increase of compaction pressing, whereas the porosity content decreased. Increase of properties, such as hardness, transverse rupture strength, and compression yield stress, occurred due the increase of compaction pressing of the compacts before sintering.