Investigation of Solid State Reaction in the Nanolaminate -Carbides in the Ternary

摘要

The main goal of this work is to contribute towards the basic understanding required to realize synthesis the MAX phases in bulk at high temperature. The phase stability of three different MAX phase systems Ti-Al-C, Cr-Al-C and V-Al-C has been investigated along this line. High purity powders were used as raw materials. They were mixed and then compacted under the pressure of 20 MPa. The compacted mixture was heated in an (Ar) atmosphere at a temperature range of (1000 - 1400) °C for (2-4) h. Finally, the sample was cooled down to room temperature. X-ray diffraction indicates that systems show a direct formation of MAX phase under these conditions. The SEM and optical microscopy results were used to confirm the structural features of the ternary phases and the less segregation or agglomeration. The results of sintering temperatures versus final density were discussed in terms of physical prthe operties evaluation and hardness to indicating the mechanical properties. Finally, the differential scanning calorimetric results, over the range of 25 to 650 °C show that the reactions in all systems related directly to the Al melting point. It is obvious that the reactions in all these systems started at -600 °C which may support this attitude. It is expected to contribute towards a better basic understanding of this fascinating class of solids. Furthermore, we try to evaluate the here-proposed novel low-temperature synthesis for other Mn+lAXn systems. This may release a new synthesis route for the mass production of materials with rather unique properties