Layer-structured Cr/Cr_xN coating via electroplating-based nitridation achieving high deuterium resistance as the hydrogen permeation barrier

Hydrogen isotope permeation through structural materials is a key issue for developing nuclear fusion energy, which will cause fuel loss and radioactive pollution. Developing ceramic coatings with high thermal shock and hydrogen resistance is an effective strategy to solve this issue. In this work, a layer-structured Cr/Cr_xN coating was successfully fabricated by a facile electroplating-based nitridation technique, which is easy, facile, and applicable to coating complex-shaped substrates. The Cr/Cr_xN coating, composed of a bottom Fe/Cr interdiffusion zone, a middle Cr layer, and a top Cr_xN layer, exhibits high bonding strength, high anti-thermal-shock ability, and high deuterium permeation resistance. Its bonding strength achieves 43.6 MPa. The Cr/Cr_xN coating remains intact even after suffering 300 thermal shock cycles under a 600 ℃–water condition. Through optimizing the nitridation temperature, the Cr/Cr_xN coating achieves a deuterium permeation reduction factor (PRF) as high as 3599 at 500 ℃. Considering its scalable fabrication technique and considerable properties, the developed Cr/Cr_xN coating may serve as a novel high-performance hydrogen permeation barrier in various fields.