3- LMACE, FSSM, Cadi Ayyad University, Av. Prince My Abdallah – B.P. 2390, 40000 Marrakech, Morocco
Email: firstname.lastname@example.org The physico-chemical properties of a material depend on its chemical composition, on the crystal or amorphous structure of its phases, but also, and in some cases essentially, on its microstructure. While in many materials the presence of porosity is considered a negative factor in other a porous microstructure proves a positive parameter sought.
The present work concerns examples of the development of the microstructure for two materials prepared under different conditions of consolidation. The correlation between the microstructure and some physical properties of consolidated materials will be investigated.
In the first example, the role of an organic additive (HOAc) on calcium aluminate cement pastes was investigated. The important dispersant effect of the additive translates into a lowering of the viscosity of the cement pastes. This better dispersion is correlated to densification and as a result an improvement of the mechanical properties of the cured material.
The second describes the parameters that influence the microstructure of a ceramic based on a Moroccan clay rich in magnesium oxide during the sintering process. The parameters studied are: i) the chemical composition of raw materials; ii) the heat treatment conditions (maximum temperature and thermal cycle). Indeed, the addition of increasing amounts of oil shale, as natural pyrogenic, on the clay material, leads to an increase of the pore size and the percentage of pore volume in the sintered material. The maximum heat treatment temperature also has a remarkable effect on the microstructure. Sintering of the clay material at a temperature between 1150 and 1250 °C leads to densification, while sintering temperature beyond 1250 °C leads to the same effects as adding oil shale. Finally, a heat treatment cycle in multi-step and longer leads to a more dense microstructure as compared to a cycle in a single step and short.