Dual Current Density (DCD) Example Calculations:

There are several configurations that can occur while solving curves where the Dual Current Density Method and these all had to be programmed into the software.  However, calculations are provided here for solving for the most typical configuration and that shown in Figures 16 and 17, namely, where there is a cuprous inflection point before the transition and a cupric inflection point afterward. 

            Cuprous Thickness  = ε_cuprous  *  K_cuprous  * t_cuprous * CD_initial

            Cupric Thickness  =  ε_cupric  *  K_cupric  ((t_transition  -  t_cuprous) CD_initial 

+  (t_cupric  -  t_transition) CD_final)

            Total Thickness =  CD_initial  (ε_cuprous  *  K_cuprous  * t_cuprous  

+  ε_cupric  * K_cupric  * (t_transition  -  t_cuprous) )  

+ CD_final * ε_cupric  * K_cupric  (t_cupric  -  t_transition)                  [5]

where CD_initial  and CD_final are the initial and final current densities, respectively and t_transition is the time at which the transition occurs during the test. 

(Basic details about our Surface Oxide Tester are found at this link.)