The exploration towards cost-effective filler metal for ceramics joining has always been the key issues for ceramics joining. Herein, we reveal that the Al metal prefers to spread on the ZrO₂ based ceramic under the air heating condition, due to the geometric limit effects by in-situ formed dense Al₂O₃ surface. Inspired by this, the joining of ZrO₂ based ceramics was realized in air with Al metal as filler, through the diffusion of Al towards ceramic side. The Al element can induce obvious interfacial bonding effect on Al₂O₃ layer and ZrO₂ ceramic, where the hybridization among the Al-p, Zr-d and O-p orbitals plays a key role. The in-situ formed Al₂O₃ layer on Al filler surface is vital for forming the fine interface (shear strength of ∼36 MPa), which results in the relief of lattice mismatch and peak stress at ceramic-filler metal transition interface.

探索高性价比的陶瓷连接填充金属一直是陶瓷连接的关键问题。在此，我们揭示了在空气加热条件下，由于原位形成的致密Al ₂ O ₃表面的几何极限效应，Al 金属更倾向于在ZrO _{2基陶瓷上扩散。}受此启发，ZrO ₂基陶瓷的接合是在空气中以铝金属为填料，通过铝向陶瓷侧扩散实现的。Al元素可以对Al ₂ O ₃层和ZrO ₂陶瓷产生明显的界面结合作用，其中Al-p、Zr-d和Op轨道之间的杂化起关键作用。这在Al填料表面原位形成的Al ₂ O ₃层对于形成精细界面（剪切强度约为36 MPa）至关重要，这导致了陶瓷-填料金属过渡界面处的晶格失配和峰值应力的消除。