Solubility Limits of La and Y in Aluminum Oxynitride at 1870°C

Abstract

The solubility limits of important dopants (La and Y) in aluminum oxynitride (AlON) were measured using wavelength-dispersive spectroscopy (WDS) mounted on a scanning electron microscope, from samples quickly cooled from 18701C. To provide saturated AlON, samples were prepared with dopant concentrations well above the solubility limit, which was confirmed by the appearance of secondary phases using X-ray diffraction, backscattered electron micrographs, and WDS. Measurements were conducted on polished samples without thermal or chemical etching. The results indicate solubility limits of 498782 and 17757128 ppm for La and Y in AlON at 18701C, respectively. The solubility limit of Mg in AlON at 18701C was found to be 44000 ppm. The relation between solubility limit and cation size is briefly discussed.

Highly Transparent AlON Pressurelessly Sintered from Powder Synthesized by a Novel Carbothermal Nitridation Method

“…The AlON powder prepared above was mixed simultaneously with suitable amounts of Mg(NO 3 ) 2 , Y(NO 3 ) 3 and La(NO 3 ) 3 , followed by forming into pellets of 20 mm in diameter and 5 mm in thickness through cold isostatic pressing at 200 MPa. The amount of Mg(NO 3 ) 2 , Y(NO 3 ) 3 , and La(NO 3 ) 3 additives was strictly controlled to give MgO, Y 2 O 3 , and La 2 O 3 dopant levels of 0.1, 0.08, and 0.025 wt%, respectively, according to the solubility limits of Mg, Y, and La in AlON reported by Miller . The pellet was embedded in a powder bed of the same chemical composition as its own, and pressurelessly sintered in a graphite furnace at 1920°C–1950°C for 8 h under nitrogen atmosphere at a heating rate of 8°C/min.…”

“…The amount of Mg(NO 3 ) 2 , Y(NO 3 ) 3 , and La (NO 3 ) 3 additives was strictly controlled to give MgO, Y 2 O 3 , and La 2 O 3 dopant levels of 0.1, 0.08, and 0.025 wt%, respectively, according to the solubility limits of Mg, Y, and La in AlON reported by Miller. 17 The pellet was embedded in a powder bed of the same chemical composition as its own, and pressurelessly sintered in a graphite furnace at 1920°C-1950°C for 8 h under nitrogen atmosphere at a heating rate of 8°C/min. The sintered samples were ground and mirror polished on both sides to a thickness of 1 mm for optical property measurement.…”

First‐Principles Insight into the Composition‐Dependent Structure and Properties of γ‐Alon

“…Although the processing, elastic strength, optical transparent properties, and thermodynamic of alon ceramics have been considered extensively in the previous investigations, relatively little work directed toward the evaluation of composition‐dependent structure and properties. A slight dependence of properties on the composition is observed when the experimental variance is not too large.…”

Water‐Based Method for Processing Aluminum Oxynitride (AlON)

“…Fang et al 21 published a structural model based on ab initio calculations that supports the constant anion model. High temperature (1870°C) solubility limits of important sintering additives (Y and La) in AlON have recently been measured 22 …”