text: One important consideration deriving from Kirkendall's work is the presence of pores formed during diffusion. These voids act as sinks for vacancies, and when enough accumulate they can become substantial and expand in an attempt to restore equilibrium. Porosity occurs due to the difference in diffusion rate of the two species.
  Pores in metals have ramifications for mechanical, thermal, and electrical properties, and thus control over their formation is often desired. The equation 
  where  is the distance moved by a marker,  is a coefficient determined by intrinsic diffusivities of the materials, and  is a concentration difference between components, has proven to be an effective model for mitigating Kirkendall porosity. Controlling annealing temperature is another method of reducing or eliminating porosity. Kirkendall porosity typically occurs at a set temperature in a system, so annealing can be performed at lower temperatures for longer times to avoid formation of pores.