  The phase diagram of the t-J-V model is discussed using a 1/N expansion in
terms of X operators. It is shown that a flux phase of d-wave symmetry is
stabilized by the Coulomb interaction V at intermediate dopings and competes
with d-wave superconductivity. Since the flux wave instability is stronger than
the superconducting one optimal doping is essentially determined by the onset
of the flux phase. Below optimal doping the flux phase coexists with
superconductivity at low and exists as a pseudo gap phase at higher
temperatures. It is also found that the flux phase boundary is much less
sensitive to impurity scattering than the boundary for superconductivity in
agreement with experiments in Zn doped La-214 and (Y,Ca)-123.
