Synthesis of polycrystalline γ-AlON powders by novel wet chemical processing

Ethanol‐Water‐Derived Sucrose‐Coated‐Al2O3 for Submicrometer AlON Powder Synthesis

“…Otherwise, AlN impurity shows up with more sucrose. According to the weight loss after decarbonization #bib23.2 wt% sucrose in precursor corresponds to 5.1 wt% carbon in derived C/Al 2 O 3 mixture, which is within the optimal value of 5.0–6.0 wt% widely employed by other investigators …”

“…Single‐phase AlON is obtained at 1700°C, a temperature at which AlON, Al 2 O 3 and AlN coexists for S 23 E 100 . Our synthesis temperature for single‐phase AlON with sucrose‐coated‐Al 2 O 3 structured S 23 E 85 is lower than those with mechanical AlN/Al 2 O 3 , C/Al 2 O 3 , Al/Al 2 O 3 mixtures (generally 1750°C–1850°C), and even our own mechanical sucrose/Al 2 O 3 mixture of S 23 E 100 .…”

“…As is known, the carbon content in C/Al 2 O 3 mixture impacts the phase composition of the final product in carbothermal synthesis of AlON, such that insufficient carbon leads to Al 2 O 3 impurity and excessive carbon results in residual AlN. 7,8,11 To validate such sucrose-coated-Al 2 O 3 precursor was applicable to AlON synthesis, a series of precursors of S 17 E 85 to S 26 E 85 with increasing sucrose content, which corresponds to increasing carbon content in pyrolyzed C/Al 2 O 3 mixtures, were attempted. Figure 6 shows the XRD patterns of the products synthesized at 1550°C for 2 h and 1720°C for another 1.5 h. Al 2 O 3 impurity decreases with sucrose increasing.…”

“…At present, widely employed methods for AlON powder synthesis include solid-state reaction, 3,4 carbothermal reduction and nitridation (CRN), [5][6][7][8][9][10][11][12] and direct nitridation. 13 Among them, CRN receives the most extensive investigations because of the low cost of the starting materials and the high quality of the final products.…”

“…Similar to them, a series of wet methods have been developed for homogeneous C/Al 2 O 3 precursor preparation, and subsequent AlON powder synthesis. [10][11][12] In the past few years, it has been reported that many organics with polar groups can disperse as a monolayer onto the surface of supports. This process is thermodynamically spontaneous, because the dispersion depresses the free energy of the system.…”