Experimental methods and procedures

Abstract

This chapter is devoted to the quantitative evaluation of D and its variation with temperature. By such measurements, two very important parameters are determined, namely, the pre-exponential factor (or ‘frequency factor’), D 0, and the activation energy, Q, which is also denoted by various symbols, such as E, H, etc. The most accurate and popular method for diffusion measurement has always been and still is the radioactive-tracer method, regardless if the solid is metallic or ceramic; however, modern techniques, specifically adapted to diffusion measurements in ceramics are SIMS, NMR, conductivity, etc. The methods of radio-active tracer, SIMS and conductivity are described in detail. The relevant equations for diffusion by these techniques comprises the topic of this chapter.