Phase formation and superconductivity in [Y1-xCax]SrBaCu2.80(BO3)(0.20)O-ywith 0.10 <= x <= 0.50

We report the phase formation and superconductivity in [Y1-xCax]SrBaCu2.80( BO3)(0.20)O-y with 0.10 less than or equal tox less than or equal to0.50 pr epared at normal pressure and temperature. The X-ray diffraction pattern sh ows that all samples have a tetragonal P4/mmm structure, indicating that th e BO3 groups were incorporated in the structure. The ZFC magnetization vers us temperature measurements under an applied field of 10 Oe using a SQUID m agnetometer, show that the materials are superconductors, with T-c approxim ate to 77K, almost independently of the Ca content. The observed difference s are related to the volume fraction of Meissner effect. In the temperature range 100-300K all samples show a typical Curie - Weiss behavior, under an applied high field of 20 KOe.