Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : AlC

Corrosion Behavior of V2AlC and Cr2AlC Materials in Acidic Media

Rana Afif Majed; Ahmad Mohammed Hasan; Russul Fadhel Faleh

Engineering and Technology Journal, 2015, Volume 33, Issue 4, Pages 845-854

This work involves the manufacturing of MAX phase materials including V2AlC and Cr2AlC using powder metallurgy as a new class of materials which characterized by regular crystals in lattice. Corrosion behavior of these materials was investigated by Potentiostat to estimate corrosion resistance and compared with the most resistant material represented by SS 316L. The experiments were carried out in 0.01N of HCl and 0.01N H2SO4 at four temperatures in the range of 303-333K. Polarization resistance values which calculated by Stern-Geary equation indicate that the MAX phase materials have more resistance than SS 316L. Optical microscopy results for corroded surfaces were confirming the resistivity of MAX phase materials.

The Effect of Aluminum Concentration on The Phase Evolution of The Ternary Ceramics Of (Ti-Al-C) System

Kahtan Khalaf Al-Khazrajy; Ahmed M.H.Al-Ghaban; Mazin Nabih Ali Hussain

Engineering and Technology Journal, 2015, Volume 33, Issue 4, Pages 973-984

In this work it has been tried to introduce this type of new materials as reproducible industrial materials and overtake some production obstacles by exploring on the direction of chemistry structure relation.
In this study composition was prepared from elemental powders (Titanium, Aluminum and carbon black) by using the powder metallurgy techniques, under different concentration due to the change in the Ti to Al concentration. The concentrations are (10% Al-80%Ti-10%C), (20%Al-70%Ti-10%C) and (30%Al-60%Ti-10%C).A compacted sample were formed in cold press using a 30ton followed by heat treatment started from (600˚C, 800˚C, 1200˚C and end in 1400˚C). The effect of Al concentration on phase evolution in the Ti-Al-C system has been investigated and the effects of cold pressing as well as heat treatment have been investigated. X-ray diffraction (XRD) and SEM technique we used for phase evolution. The density and porosity percentage were calculated using Archimedes method, also the micro hardness was measured under that different process.
The XRD, SEM data shows that, by increasing the Al concentration intermediate phases like TiAl3 and/or TiAl appear to be stable instead of the H phase. By raising the temperature, transformations accurse to produce both MAX phase structures in this system Ti2AlC and Ti3AlC2. This production pathway from the intermediate phase to ternary phase is suggested to be the more accepted, and it depends on atomic mobility. No evidence for the direct formation of MAX phases from elemental powders is found which may explain the need of high temperatures to produce such phases since the breaking of bonds is required for the intermediate phase. Finally, the use of pre-heating process decreases the temperature of formation of the MAX phases with the effect of the highest Al concentration.