Ceramic—metal interfaces

Wu R and Freeman A J 1994 Magnetism at metal-ceramic interfaces effects of a Au overlayer on the magnetic properties of Fe/MgO(001) J. Magn. Magn. Mater. 137 127-33... 

Metal-ceramic interface interactions wetting and interfacial energies... 

The phenomena which occur in metal-ceramic interface interactions are of great importance in catalysis. There are two types of interactions those which depend on the epitaxy between the metal and the support and those which are independent of it. Strong metal-support interactions are described by the term SMSI. 

Detailed HRTEM characterization of the specimens showed that all metal-ceramic interfaces in the two different nanocomposites had thin ( 1 nm thick) amorphous films (see Fig. 11.5). In addition, occluded particles were found inside the alumina grains which also had thin amorphous films at their interfaces with alumina. Analytical microscopy showed the films to contain Ca, Si, and Al.41 Hamaker coefficients were calculated for metal-ceramic interfaces in the presence of a Si02-based film, which indicated that a stronger attractive force is expected for intergranular films at metal-alumina interfaces,... 

The ability to modify the metal-ceramic interface in nanocomposites by the formation of intergranular films holds exciting prospects. From a thermodynamic point of view, the existence of a film at equilibrium indicates a lower interface energy than an interface without a film. This indicates the potential to increase the adhesion of interfaces, although experimental investigations are required to fully evaluate this effect. However, the promotion of particle occlusion due to the presence of the films has been shown,28 and this means that a new method to modify and control the microstructural evolution of nanocomposites is available, as discussed in the next section. 

Some reports have cited bridging across the relatively ductile metal particles as mechanisms which contribute to the increase in fracture strength.54 Other reports demonstrate cracks propagating at the metal-ceramic interfaces,... 

Avishai, A., Scheu, C. and Kaplan, W.D., Amorphous films at metal-ceramic interfaces , Zeitschrift fur Metallkunde, 2003 94 272-276. 

By definition, brazes have a different composition from the components they are used to join and hence interdiffusion will occur during and after interface creation. Reference has been made already to the detrimental effects of the growth of thick reaction products at metal-ceramic interfaces and similar effects can occur with metal-metal systems. Thus it is not good practice to use A1 brazes for the joining of steel or Cu components or to use Ni brazes containing Si for the joining of refractory metal components because of the rapid formation of fragile layers of intermetallic compounds. 

E.D. Hondros, Bonding of Metal/Ceramic Interfaces, International Conference Science Hard Materials, Institute of Physics ConferenceSer, Vol.75(No.2), 1986,p.l21. 

ATOMIC-LEVEL PROPERTIES OF THERMAL BARRIER COATINGS CHARACTERIZATION OF METAL-CERAMIC INTERFACES... 

Theoretical methods offer the opportunity to explore structure-property relationships in ideal metal-ceramic interfaces. Ultimately, improved understanding of the causal sequence leading to a particular interface structure and set of properties would enable further optimization of manufacturing parameters. Atomistic modeling constitutes the perfect laboratory in this respect. Within the limits of the specific approximations used for interatomic interactions, physical properties may be resolved to arbitrary accuracy and competing effects may be separated. 

P. Bliichl, G. P. Das, H. F. Fischmeister and U. Schonberger, in Metal-Ceramic Interfaces, Acta-Scripta MetaJlurgica Proceedings, Series 4, Eds. 

Metal-Ceramic Interfaces, Acta-Scripta Metall. Proc. 4 (edited by M. Riihle, A. G. Evans, M. F. Ashby, J. P. Hirth, Pergamon Press, 1990). 

Proceedings of the International Symposium on Metal-Ceramic Interfaces, Acta. Metall. Mater. S40 (1992). 

Chandra N, Li H, Shet C, Ghonem H, Some issues in the application of cohesive zone models for metal-ceramic interfaces, Int. J. Solids Structures 39, 2002, 2827-55. 

Suo Z. and Shih C. R, Models for Metal/Ceramic Interface Fracture, chap. 12 of Fundamentals of Metal-Matrix Composites, edited by S. Suresh, A. Mortensen and A. Needleman, Butterworth-Heinemann, Oxford England, 1993. 

The morphology of the metal-ceramic interface depends upon the type of interaction that has occurred. If only physical interaction has occurred, the structure of the metal and ceramic is unchanged. However, if a chanical reaction occurs, the morphology is affected depending upon whether solid-solid or solid-liquid reactions occur and if new interfacial phases are formed. The formation of new interfacial phases alters not only the microstructure but also the physical and mechanical properties. These interfacial phases or reaction product layers are a consequence of the reactions needed to cause wetting of the ceramic. One can consider the reaction product layers as chemical bridges between the metal and ceramic. 

The metal-ceramic interface constitutes a class of materials with extremely relevant properties which are crucial to a large series of technological applications such as anticorrosion protection, microelectronics and also in the chemical industry where they are commonly employed as catalysts. For obvious reasons, the preparation for these different applications depends on the final use of the material and both metals on oxides or oxides on metals can be prepared. 

A. Passerone and M.L. Muolo, Metal-ceramic interfaces wetting and joining processes. International Journal of Materials and Product Technology, 20(5-6), 420-439 (2004). 

Wetting/dewetting is also a concern for nonoxides (especially when you want to join them to other materials) and for metal/ceramic interfaces such as the metal/Si, metal/Si02, and metal/Si3N4 interfaces in the electronics industry and systems such as AI/AI2O3, which is important in protecting metals against corrosion. 

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 ... 

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