Metal ceramic interfacial strength

In principle, an equality between the thermodynamic work of adhesion of liquid-solid systems and the work needed to separate an interface might be expected for simple systems and this has been observed for failure of adhesive-polymer interfaces bonded by van der Waals forces, (Kinloch 1987). Similarly, empirical correlations of interfacial strengths and work of adhesion values of solidified interfaces have been reported for some nominally non-reactive pure metal/ceramic systems. However, mechanical separation of such interfaces is a complex process that usually involves plastic deformation of the lattices, and hence their works of fracture are often at least ten and sometimes one hundred times larger than the works of adhesion, (Howe 1993). Nevertheless, for non-reactive metal/ceramic couples, it is now widely recognised that the energy dissipated by plasticity (and as a result the fracture energy of the interface) scales with the thermodynamic work of adhesion (Reimanis et al. 1991, Howe 1993, Tomsiaet al. 1995). 

In Section 15.14 we note that dislocations can be present at metal/ceramic interfaces. When is this most likely when is it least likely How will the interfacial energies and strengths differ ... 

Materials science associated with fracture mechanics has mainly been confined to composite materials such as concrete, ceramics and metals. Much of the emphasis of the research has been on preventing fatigue and failure rather than designing for it to occur. The way a structure deforms and breaks under stress is crucial for properties such as flow and fracture behaviour, sensory perception of structure, water release and the mobility and release of active compounds. In the case of foods, the ability to break down and interact with the mouth surfaces provides texture and taste attributes. The crack propagation in a complex supramolecular structure is highly dependent on the continuous matrix, interfacial properties and defects and the heterogeneity of the structure. Previous structure-fracture work has dealt with cellular plant foods, and it has been demonstrated that the fracture path differs between fresh and boiled carrots due to cellular adhesion and cell wall strength as well as cell wall porosity and fluid transport (Thiel and Donald 1998 Stoke and Donald 2000 Lillford 2000). 

K. Otsuka, T. Usami, and M. Sekihara, Interfacial Bond Strength in Alumina Ceramics Metallized and Cofired with Tungsten, Ceramic Bull., Vol. 60, No. 5, (1981), pp. 540-545. 

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