in this non-steady (transient)-state diffusion condition, determine the carburizing time necessary in hours to achieve a carbon (c) concentration of 0.45 wt% at a position 2 mm into an iron (fe)–c alloy that initially contains 0.20 wt% c. the surface concentration is to be maintained at 1.30 wt% c, and the treatment is to be conducted at 1000 c (i.e., 1273 k)
