Iranian Journal of Materials Science and Engineering

• Two different precursors (MgO and Mg(NO₃)₂ . 6H₂O)  used to prepare MgO support.
• Although single phase of MgO as support material was achieved from two different precursors, they caused different catalyst/support morphology and grain size.
• By employing MgO precursors more MgFe₂O₄ phase was obtained which improved homogeneous distribution of catalyst particles.

 Particularly mullite zirconia composites are materials with important technological applications due to their good properties such as toughness, chemical stability, and high-creep resistance. In practice they are employed in the glass industry and where high chemical and corrosion resistance are required.
 
The purpose of the current research was to investigate the effect of La2O3 additive in the reaction sintering process of conventional raw materials on thermal, microstructure and mechanical properties of mullite–zirconia composites.
 
Usually, mullite zirconia composites can be obtained by various methods such as direct powder compact of mullite and zirconia, reaction sintering of alumina, silica and zirconia; reaction sintering of alumina and zircon. Similarly, various researchers have studied the effect of different additives on the formation and sintered characteristics of the mullite-zirconia composite. It was found that the addition of lanthanum oxide decreased the densification temperature and significantly improved the thermal shock resistance of the mullite–zirconia composites. In addition to the mullite zirconia composites studies containing La2O3 originality of our work is to observe the effect of La2O3 addition to kaolinite, alumina and zircon mixture synthesized from conventional raw materials and so to form a new reference and field of interest.

• Bulk nanostructured Co_1-xCu_xSbS paracostibite were synthesized by a new route.
• A reversible p- to n-type transition at 500 K was established in CoSbS.
• A maximum power factor of 0.3299 mW/mK² was obtained for un-doped CoSbS at 723 K.
• Co_0.06Cu_0.04SbS₄ solid solution showed a maximum ZT value of 0.12 at 723 K.

• A specific die design of spread extrusion process was used to fabricate AM60 Mg alloy dish-shaped samples.
• Dynamic recrystallization was observed as a result of processing at elevated temperature.
• Samples with a mean grain size of 14 µm were produced.
• Microhardness successfully increased to 70 Hv from an initial value of 51 Hv.

• Heat treatment improved the hardness at 750°C, 850°C and 950°C.
• The corrosion resistance increased with heat treatment in 0.1 N NaCl and 1% citric acid as compared to artificial saliva.
• Clinically, high hardness of Co-Cr leads to the early wearing of tooth structure under occlusal load.
• Corrosion rate significantly reduced at 650°C as compared to the as-cast condition making it favourable in clinical application.
• Cell viability of gingival fibroblasts is more than 90% at 650°C.

• Li₂TiO₃ nanocrystallites synthesized by hydrothermal method and subsequent heat treatment.
• Densification curves of the synthesized powder constructed by dilatometry.
• The activation energy value and dominant mechanism of sintering are determined.

• Zr-doped NiAl coatings were prepared by aluminizing and then Zr sputtering.
• Zr decreased Al outward diffusion during oxidation and resulted in less oxide layer thickness.
• The coating of 300 nm Zr-NiAl exhibits the best spallation resistance.