  We present a time series of 8 - 13 $\mu$m spectra and photometry for SN 2014J
obtained 57, 81, 108, and 137 d after the explosion using CanariCam on the Gran
Telescopio Canarias. This is the first mid-IR time series ever obtained for a
Type Ia supernova. These observations can be understood within the framework of
the delayed detonation model and the production of $\sim$0.6 $\rm M_\odot$ of
$^{56}$Ni, consistent with the observed brightness, the brightness decline
relation, and the $\gamma$-ray fluxes. The [Co III] line at 11.888 $\mu$m is
particularly useful for evaluating the time evolution of the photosphere and
measuring the amount of $^{56}$Ni and thus the mass of the ejecta. Late-time
line profiles of SN 2014J are rather symmetric and not shifted in the rest
frame. We see Argon emission, which provides a unique probe of mixing in the
transition layer between incomplete burning and nuclear statistical
equilibrium. We may see [Fe III] and [Ni IV] emission, both of which are
observed to be substantially stronger than indicated by our models. If the
latter identification is correct, then we are likely observing stable Ni, which
might imply central mixing. In addition, electron capture, also required for
stable Ni, requires densities larger than $\sim$$1 \times 10^9$ g cm$^{-3}$,
which are expected to be present only in white dwarfs close to the
Chandrasekhar limit. This study demonstrates that mid-IR studies of Type Ia
supernovae are feasible from the ground and provide unique information, but it
also indicates the need for better atomic data.
