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Ceramic-metal joining denotes the set of processes by which a monolithic ceramic or ceramic component is bonded to a metal or alloy component to produce a single, load-bearing assembly that combines the high-temperature strength, hardness, and chemical stability of the ceramic with the ductility and toughness of the metal ^[1]. The central scientific difficulty is that the two materials are chemically and thermally mismatched: the ceramic is generally non-wetting to conventional molten braze alloys, and its lower coefficient of thermal expansion generates residual stress on cooling from the joining temperature. This is overcome by active metal brazing, in which a reactive element—most commonly titanium, zirconium, or hafnium—is alloyed into an Ag–Cu or Au–Ni filler so that it segregates to the ceramic interface and chemically reduces or reacts with the ceramic surface, forming a thin reaction layer of oxides, nitrides, or carbides that permits wetting and metallurgical adhesion ^[2]. Diffusion bonding, brazing through a prior metallized layer, and interlayer insertion are alternative routes that control the interfacial reaction and redistribute thermal stress. The resulting joint is therefore defined by an engineered interfacial reaction zone between the ceramic and the filler rather than by simple fusion welding ^[3].