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 Dy 2 Zr 2 O 7 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 ZrO 2 and Dy 2 O 3 powders. The influence of pre-calcining temperature on the content of phases, the particle sizes, on the sinterability of the mixture of Dy 2 O 3 and ZrO 2 powders has been investigated. It was found that when the pre-calcination was conducted at 1200°C for 2 h, the powder contains 4 mol% Dy 2 Zr 2 O 7 , 18 mol% m-ZrO 2 , 30 mol% Dy 2 O 3 , and about 50 mol% t/c-ZrO 2 which is beneficial for the sintering of pore-free Dy 2 Zr 2 O 7 ceramics. The mechanism is discussed in the paper. The transparency of the sintered Dy 2 Zr 2 O 7 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.