Fabrication of near-infrared transparent Dy2Zr2O7 ceramic by controlled pre-calcination of powders

Fabrication of transparent or pore-free oxide ceramics usually requires sintering in a vacuum or reducing atmosphere. In the present paper, a near-infrared transparent Dy2Zr2O7 ceramic was prepared by ordinary pressureless sintering under the air atmosphere, with a controlled pre-calcining of raw powders process. The key point of the process is to control the content of the phases by pre-calcination of the starting mixture of ZrO2 and Dy2O3 powders. The influence of pre-calcining temperature on the content of phases, the particle sizes, on the sinterability of the mixture of Dy2O3 and ZrO2 powders has been investigated. It was found that when the pre-calcination was conducted at 1200 degrees C for 2 h, the powder contains 4 mol% Dy2Zr2O7, 18 mol% m-ZrO2, 30 mol% Dy2O3, and about 50 mol% t/c-ZrO2 which is beneficial for the sintering of pore-free Dy2Zr2O7 ceramics. The mechanism is discussed in the paper. The transparency of the sintered Dy2Zr2O7 ceramic was measured, and their transmittance is about 63% at 1450 nm and 73% at 1900 nm. This work provides a simple and convenient way to prepare the near-infrared transparency ceramic without special sintering facilities.