Amorphous Silicon Oxynitride-Based Powders Produced by Spray Pyrolysis from Liquid Organosilicon Compounds

Abstract

Silicon oxynitrides (SiOxNy) have many advantageous properties for modern ceramic applications that justify a development of their new and efficient preparation methods. In the paper, we show the possibility of preparing amorphous SiOxNy-based materials from selected liquid organosilicon compounds, methyltrimethoxysilane CH3Si(OCH3)3 and methyltriethoxysilane CH3Si(OC2H5)3, by a convenient spray pyrolysis method. The precursor mist is transported with an inert gas or a mixture of reactive gases through a preheated tube reactor to undergo complex decomposition changes, and the resulting powders are collected in the exhaust filter. The powders are produced in the tube at temperatures of 1200, 1400, and 1600 °C under various gas atmosphere conditions. In the first option, argon Ar gas is used for mist transportation and ammonia NH3 gas serves as a reactive medium, while in the second option nitrogen N2 is exclusively applied. Powder X-Ray Diffraction (XRD) results confirm the highly amorphous nature of all products except those made at 1600 °C in nitrogen. SEM examination shows the spheroidal particle morphology of powders, which is typical for this method. Fourier Transform Infrared (FT-IR) spectroscopy reveals the presence of Si–N and Si–O bonds in the powders prepared under Ar/NH3, whereas those produced under N2 additionally contain Si–C bonds. Raman spectroscopy measurements also support some turbostratic free carbon C in the products prepared under nitrogen. The directly determined O- and N-contents provide additional data linking the process conditions with specific powder composition, especially from the point of view of oxygen replacement in the Si–O moieties formed upon initial precursor decomposition reactions by nitrogen (from NH3 or N2) or carbon (from the carbonization of the organic groups).

Experimental Investigations into the Pyrolysis Mechanism and Composition of Ceramic Precursors Containing Boron and Nitrides with Different Boron Contents

“…The structural evolutions of the pyrolysis products were characterized by FTIR, and the results are shown in Figure 5 . There are a series of characteristic absorption peaks in the products of 15 M-400 °C, in which 3408 cm −1 belongs to the stretching vibration of N-H [ 30 ], 2960 cm −1 and 2900 cm −1 belong to the C-H bond of (Si-CH 3 ) silyl methyl [ 31 ], 2135 cm −1 belongs to the Si-H [ 32 ] bond, the broad peak near 1400 cm −1 belongs to the B-N structure [ 33 ], 1261 cm −1 belongs to the characteristic bending vibration of silyl methyl, and the wide peak near 900 cm −1 belongs to the Si-N structure [ 34 ]. During the heating up to 600 °C, the N-H signal increased and broadened obviously, while the silyl-methyl-related signal nearly disappeared, indicating that the ammonolysis process and decarbonization reaction occurred during heat treatment.…”

Hierarchical microstructure growth in a precursor‐derived SiOC thin film prepared on silicon substrate

“…The formation of Si 3 N 4 is reasonable and is a consequence of the reaction of N 2 gas with the in situ formed SiO 4-x C x . The reaction has a minimal contribution during the thermal decomposition of SiOC/Si/SiC and is more favored at temperature between 1400 and 1600 • C. 47 It is obvious from the SAED patterns that multiple crystalline phases exist in the segregation. On the TEM image, it is apparent that 4H-SiC and β-Si 3 N 4 exist as fragments distributed in the area of the segregation.…”

Fabrication and Characterization of Narrow-Wavelength Phosphors of Tb-Doped Yttrium-Silicon-Aluminum Oxynitride Using Spray Pyrolysis

“…Among phosphor materials, the oxynitridosilicates class matrix is superior to other materials owing to its good mechanical and chemical stability [20,21], high thermal quenching stability [17], prolonged luminescence half-life [12,22], and ability to adjust the wavelength [4,20]. Green phosphor materials are predominantly synthesized using various methods, including solid-state [17], sol-gel [23], and spray pyrolysis (SP) [24]. The conventional approach for solid-state reactions is simple, easy to implement, and has a wide range of chemical compatibilities [25].…”

“…However, it has the disadvantages of a long reaction time and high energy loss during calcination to remove the residue, which can hinder the enhancement of the luminescent properties of the phosphor particles [23,26]. The SP method has been used to circumvent these issues [24,27]. Compared with the aforementioned techniques, SP offers several advantages, including less contamination [24], compatibility with the continuous process [28], fast processing time (∼1 h) [27], and morphological flexibility [29,30].…”

“…The SP method has been used to circumvent these issues [24,27]. Compared with the aforementioned techniques, SP offers several advantages, including less contamination [24], compatibility with the continuous process [28], fast processing time (∼1 h) [27], and morphological flexibility [29,30]. Furthermore, several high-purity micron-sized phosphor materials of various morphology were successfully synthesized using this method.…”