Low‐pressure fabrication of IR‐transparent Y ₂ O ₃ via spark plasma sintering

Abstract

Different pressures of 80 and 90 MPa were applied to produce Y 2 O 3 ceramics by spark plasma sintering in this work. Effects of pressure were investigated on densification, microstructure, infrared (IR) transmission and mechanical properties. It was found that applying higher pressure led to finer microstructure and consequently higher hardness and fracture toughness. An IR-transparent Y 2 O 3 ceramic with 60% transmission at wavelength of 5 µm was obtained by sintering at 1300°C under uniaxial pressure of 90 MPa. This sample had an average grain size of 0.76 µm and hardness and fracture toughness of 9.37 GPa and 1.60 MPa.m 1/2 , respectively.

An Improving Densification in Spark Plasma Sintering Ultrafine-grained Y2O3 Transparent Ceramic by Particle Fracture and Rearrangement

“…However, when the nanorod powders were used in the present work, transparent ceramic with a transmittance of more than 80% in the infrared band was obtained at only 1300 °C. Moreover, the transmittance of Y 2 O 3 transparent ceramic obtained at 1300 °C as reported in other work is only 62.1% in the infrared band [39]. Although a higher thickness of the sample will reduce the transparency, it has no transmittance in the visible light band.…”

“…It can be seen from Table 1 that the transmittances of Y 2 O 3 transparent ceramics via SPS method in the visible light band are di cult to exceed 80%, which are generally lower than the transmittances in the infrared range. The sintering temperatures to prepare Y 2 O 3 transparent ceramics with good optical properties in most cases need to exceed 1400 °C [36][37][38][39]. However, when the nanorod powders were used in the present work, transparent ceramic with a transmittance of more than 80% in the infrared band was obtained at only 1300 °C.…”

An effective strategy for preparing transparent ceramics using nanorod powders based on pressure-assisted particle fracture and rearrangement

“…As a comparison, the transmittance of the Y 2 O 3 transparent ceramics sintered at the same temperature by the SPS, as reported in Ref. [46], is only 62.1% in the IR band. Besides, although the aforementioned sample (3.5 mm) is thicker than that in this study (1.0 mm), it has no transmittance in the visible light band.…”

“…It can be seen in Table 1 that, the transmittance of the Y 2 O 3 transparent ceramics via the SPS method in the visible light band is difficult to exceed 80%, which is generally lower than the transmittance in the IR range. The fabrication of the Y 2 O 3 transparent ceramics with good optical properties needs high sintering temperatures or sintering aids to promote the densification [35,[43][44][45][46]. However, when the nanorod powders were used in the present work, the transparent ceramics with a transmittance of more than 80% in the IR band were obtained without any sintering aids.…”