A thermodynamic criterion has been applied to determine the reliabilit
y of contact metals such as silver, aluminium, gold, chromium, and tit
anium on bismuth and yttrium based high temperature superconductors (H
TSC). The chemical stability is presumed for positive heat of reaction
s, i.e., DELTAH(reaction) > 0, when a metal reacts with all the possib
le oxides present in the superconducting material. Based on these calc
ulations, metals for reliable contacts to HTSCs are proposed.