共晶陶瓷中间层超快高温钎焊SiC陶瓷的工艺及机理研究

Ceramic brazing components have considerable application value in aerospace and nuclear energy fields. However, the high-temperature performance of ceramic brazed joints faces a bottleneck under service conditions above 1000°C. This study developed a novel ultrafast high-temperature brazing technology using Joule heating and successfully achieved brazing between eutectic ceramic interlayers and SiC ceramic substrates, with joint high-temperature resistance exceeding 1500°C. The fully ceramic brazed joint with a room temperature shear strength of 150 MPa is achieved by employing carbon fiber braided preform as a resistive heating element, which maintained temperature stabilization for 25 s under 40 A before power termination. In the Y₂O₃-Al₂O₃-ZrO₂ eutectic ceramic interlayer, the ZrO₂ component reacts with SiC at high temperatures to form a micrometer-thick zirconium-rich reaction layer at the interface. Simultaneously, the molten eutectic ceramic infiltrates the substrate to form an interpenetrating network under a pinning effect, thereby enhancing the mechanical properties of the joint. When the heat input exceeds the critical threshold, the SiC substrate undergoes severe decomposition, resulting in the excessive diffusion and migration of Si elements into the brazed region, reducing the shear strength to below 100 MPa. Compared with conventional slow high-temperature brazing methods, ultrafast high-temperature brazing helps avoid long-term atmospheric infiltration into the joint, resulting in dense and defect-free all-ceramic joints. Compared with conventional metal interlayer brazing methods, the all-ceramic joints help avoid stress concentration, with reduced peak residual stresses and a more uniform distribution. This study provides a full-ceramic joint solution for developing high-temperature-resistant ceramic brazed components.