Efficient Optimum Design of Metal with Strong Adhesion to Ceramics with a Combination of Orthogonal Array and Response-Surface Method

Abstract

A technology for efficiently designing an appropriate metal material with strong adhesion to a ceramic material was developed by using a combination of an orthogonal array and a response-surface method, and it was applied to the interface adhesion between metals and an example ceramic, alumina (Al2O3) in nanoscale thin-film devices. In this optimum-design technology, at the first step, important factors that significantly influence the adhesion strength were selected from various factors that characterize metal materials by using an orthogonal array with molecular simulations. As a result, the short-side and long-side lattice constants a and b were selected from four metal-material factors (a, b, the electronegativity, E, and the surface energy density, S). At the second step, the adhesion strength was described as a function of the selected important factors by using a response-surface method. From this function, the ideally most appropriate values for a and b that made the adhesion strength maximum were obtained. The obtained optimum values for a and b agreed well with the lattice constants of the ceramic (alumina). At the third step, the most appropriate metal material whose lattice constants were close to the optimum values, which were the lattice constants of the ceramic (alumina), was selected by use of the molecular simulation results of lattice constants. As a result, a Pd alloy with Ni, whose lattice constants were almost the same as the optimum values, was selected as the most appropriate metal material with the strongest adhesion to the ceramic (alumina).

Materials Optimization Technology for Efficiently Designing Strong-Adhesion Interfaces by Use of Orthogonal Array and Response-Surface Method

“…In this case, the author could not determine the optimal lattice constants that made the adhesion to alumina only by using orthogonal arrays. So, the author developed a technology for optimizing the lattice constants of metals by using a response-surface method 3) as well as orthogonal arrays. The basic idea of material design in the author's technology shown in Fig.…”

“…In the sensitivity analysis, the results of molecular simulations of the objective material property that is paid attention to are used as input data. At the second step, the objective material property, which is the adhesion in this paper, is described as a function of the selected important factors by using a response-surface method 3) with the molecular-simulation results that are also used at the first step. By using this function, the most appropriate values of the factors that optimize the objective material property, which is adhesion strength in this paper, are determined.…”

“…In this case, the author could not determine the optimal lattice constants that made the adhesion to alumina only by using orthogonal arrays. For this reason, the author developed a technology for optimizing the lattice constants of metals by using a response-surface method 3) as well as orthogonal arrays. This response-surface technology combined with orthogonal arrays was applied to select metals with strong adhesion to alumina (Al2O3) 3) , as described in Chapter 3.…”