Ti-Al Membranes for Microfiltration
Porous membranes made of Ti – 48 at. % Al intermetallic compound was obtained by elemental powder synthesis. These disks can be used as microfiltration membranes due to their low pores size and interconnected porosity. During this study titanium (purity 99.5%) and aluminum (purity 99 %) with low particle size range were mixed in corresponding ratios. The powder mixture was pressed at 500 MPa and the samples were heat treated in two stages. In the first step is the forming of Al3Ti compound by a solid state reaction at a temperature of 640 °C, slightly below the melting point of aluminum. In the second step the Ti-Al compound was formed at the temperature of 1300 °C and the sintering the por…
Studies and Researches on the Obtaining of Sintered Gradual Porous Structures by Irregular Nickel Powders Sedimentation
The aim of this work is to obtain sintered porous membranes with graded structure for microfiltration by sedimentation and sintering of metallic powders. Our previous studies have demonstrated the possibility of obtaining sintered porous materials with graded structure by sedimentation. In this paper, irregular nickel particles were used having a grain size in the 2-90 µm range evaluated using scanning electron microscopy and laser scattering particle size analyzer. The powders were sedimented into a sintering die in a sedimentation medium consisting of water and dispersant agent. After drying, the samples were sintered at 1000°C for 10 minutes in vacuum (~1•10-3 Pa). The structures obtaine…
Open Cell Al-Si Foams by a Sintering and Dissolution Process
Open cell foams from AlSi12 alloy were successfully fabricated by the Sintering and Dissolution Process, using NaCl as space holder (60 %). The size of the aluminum alloy powder is less than 45 μm, while the space holder powder size is 315-500 μm, 630-800 μm and 800-1250 μm respectively. The appropriate quantities of alloy powder and salt were mixed and cold pressed at 250 MPa. The sintering process was done at 500 °C and 545 °C, in vacuum (10-5 torr) for 10, 20 and 30 minutes respectively. The space holder was eliminated by holding the sintered samples in running hot water (70 °C). After the salt was dissolved, the samples were dried and the mass loss was analyzed. Keywords: Aluminum foam…