Effects of Sintering and Annealing Temperature on Fabrication of Transparent Lu₂Ti₂O₇ by Spark Plasma Sintering

Abstract

Transparent lutetium titanate (Lu2Ti2O7) was fabricated by reactive spark plasma sintering. Effects of sintering and annealing temperature on the microstructure, optical and mechanical properties of Lu2Ti2O7 bodies were investigated. Pyrochlore Lu2Ti2O7 was obtained at above 1273 K and a full dense specimen was obtained above 1373 K. The average grain size increased from 0.22 to 10.85 μm up to 1773 K and abnormal grain growth occurred at 1823 K. The Lu2Ti2O7 body obtained at 1723 K for 2.7 ks for sintering and 1023 K for 21.6 ks for annealing shows the maximum transmittance with a thickness of 1 mm of 74% at a wavelength of 2000 nm. The hardness was dependent on the relative density and the grain size, while the fracture toughness slightly decreased with increasing annealing and sintering temperatures.

Nd3+-doped Lu2O3 transparent sesquioxide ceramics elaborated by the Spark Plasma Sintering (SPS) method. Part 1: Structural, thermal conductivity and spectroscopic characterization

“…Our main goal by choosing SPS method is to take benefit of poly-crystal made during a short time sintering, to avoid strong segregation of rare earth dopants due to lower sintering temperature than crystals, to find strong mechanical properties with small grains at a low cost [12,13]. Commercial Lu 2 O 3 (Shin-Etsu Rare Earth, Tokyo, Japan; 99.99% purity), Nd 2 O 3 (Wako Pure Chemical Co. Inc., Tokyo, Japan; 99.9% purity) and LiF (Wako Pure Chemical Co. Inc., Tokyo, Japan; 99.9% purity) powders were used as the starting materials.…”

“…At first, we have chosen to synthesize Nd 3+ -doped Lu 2 O 3 transparent ceramics by the Spark Plasma Sintering (SPS) method, a new and non-conventional one [12][13][14] as compared with conventional vacuum sintering or hot pressing methods. This new technique is comparatively simple and consumes less time than other conventional sintering methods.…”

Field‐Assisted Sintering Technology/Spark Plasma Sintering: Mechanisms, Materials, and Technology Developments

“…When using intermediate pressures and standard graphite tools, a two-step pressure schedule might be advantageous to homogenize the microstructure. [144,150] However, possible contamination by carbon at least at the contact surface with graphite parts [151] and the creation of light-absorbing oxygen vacancies due to reducing conditions [152] both lower the in-line transmission. Usually, a postsintering annealing step in air improves the transparency.…”

The influences of possible factors on preparation and characterization of Lu2Ti2O7 nano-wires

“…Pure Lu 2 Ti 2 O 7 phase is virtually impossible at a temperature o1000 1C [11]. In our studies, the calcinations temperature is only 1000 1C.…”