  We use high resolution collisionless $N$-body simulations to study the
secular evolution of disk galaxies and in particular the final properties of
disks that suffer a bar and perhaps a bar-buckling instability. Although we
find that bars are not destroyed by the buckling instability, when we decompose
the radial density profiles of the secularly-evolved disks into inner S\'ersic
and outer exponential components, for favorable viewing angles, the resulting
structural parameters, scaling relations and global kinematics of the bar
components are in good agreement with those obtained for bulges of late-type
galaxies. Round bulges may require a different formation channel or
dissipational processes.
