Fabrication of near‐infrared transparent Dy ₂ Zr ₂ O ₇ ceramic by controlled pre‐calcination of powders

Abstract 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.