$GdBa_2Cu_3Ox$ superconductor disks and Y-Bi-Ba-Cu-O superconductors in thick film-form have been prepared by conventional ceramic powder compacting method and by screen printing and sintering method. X-ray powder diffraction patterns and SEM microphotographs were taken to analyse phase and microstructure, and electrical and magnetic prorerties have been investigated by 4-point probe and levitation methods. The rates of calcination and formation of the superconducting phase is larger in nitrogen atmosphere than in air. Sintering atmosphere does affect the values of electrical resistivity above the temperature (Tc) but its effect on Tc itself is negligible. The microstructure of the $GdBa_2Cu_3Ox$ were similar to those of $YBa_2Cu_3Ox$. The effect of the magnetic Gd atom is to make the superconductor weak on magnetic field.
$YBa_2Cu_3Ox$ films coated on magnesia substrates, sintered at 890°C in air or oxtgen atmosphere do not exhibit superconducting properties whereas it shows Tc of 75K when sintered in nitrogen atmosphere. Electrical characteristics of normal state (above Tc) changed from semiconductor to metallic type as the sintering temperature increased from 890°C to 925°C.
The effects of 2w/o $Bi_2O_3$ in $YBa_2Cu_3Ox$ films is to enhance sintering without changing Tc but to increase the electrical resistivity above Tc probably by the formation of residual $Bi_2O_3$ film in the grain boundary. The substitution of Bi into the $YBa_2Cu_3Ox$ enhances the sinterability and reduces the electrical resistivity by increasing the contact area between grains. Thus $Y_{0.85}Bi_{0.15}Ba_2Cu_3Ox$ films on magnesia substrate with Tc 80K could be obtained by a screen printing and sintering method.
