High Reactive MgO‐Y₂O₃ Nanopowders via Microwave Combustion Method and Sintering Behavior

Abstract

To decrease the sintering temperature of MgO-Y 2 O 3 composites to avoid undesired grain coarsening, high reactive MgO-Y 2 O 3 nanopowders were synthesized via microwave combustion method. The degree of combustion was enhanced effectively by adding an extra oxidant ammonium nitrate. The as-synthesized MgO-Y 2 O 3 nanopowders,~18 nm in size, showed high specific surface area of 64.55 m 2 /g and low agglomeration. Relative density of 98% was obtained when sintered at a low sintering temperature of 1350°C. The high reactivity can be attributed to the lower activation energy Q (131.13 kJ/mol), compared with samples without extra oxidant (192.97 kJ/mol).

Electromagnetic and wave absorbing properties of Fe-doped polymer-derived SiCN ceramics

“…The transformation of nano-Fe 2 O 3 to a-Fe could be attributed to the formation of inner reductive atmosphere of hydrocarbons and hydrogen (C x H y , H 2 ) during the pyrolysis process. [14][15][16] According to the Scherrer equation, 17 the size of a-Fe crystallites and graphite could be calculated to be about 35 nm and 20 nm, indicating the simultaneous formation of a-Fe and graphite crystallite in the Fe-doped SiCN ceramics. Fig.…”

Scalable and tunable Y2O3‐MgO composite for infrared transparency applications

“…For the preparation of YM composite, ball milling has been used as a combination with other routes (above‐mentioned methods) but not as a single primary method 28–31 . Fabrication of YM composite using commercial powders by using only ball‐milling method eliminates an extra step in the synthesis process, saving time and reducing costs.…”

“…For the preparation of YM composite, ball milling has been used as a combination with other routes (above-mentioned methods) but not as a single primary method. [28][29][30][31] Fabrication of YM composite using commercial powders by using only ball-milling method eliminates an extra step in the synthesis process, saving time and reducing costs. The variations in ball milling parameters are mostly constrained to the milling speed and time, ballto-powder weight ratio, milling atmosphere, and temperature.…”