Si3N4 ceramics were joined with a Si3N4–Al2O3–RE2O3–Si O2(RE=Y or Lu) powder mixture via in-situ formed RE-Si-Al oxynitride glass interlayer. The effects of bonding temperature, holding time and rare-earth element type on the microstructure and properties of the joints were investigated. The oxidation behavior of the joints was analyzed. The densification and uniformity of the seam as well as the diffusion between Y-Si-Al-O-N glass as a solder and Si3N4 matrix are improved when the holding time is increased...