An article of manufacture useful as the base for an electronic circuit board is a substrate with an enamel layer having a heterogeneous structure containing at least two different phases obtained by applying a homogeneous, alkali-containing enamel powder to the substrate followed by heating at 850 DEG C. to 1,000 DEG C. wherein the enamel power has the composition as follows: -SiO2 40-50% by weight -Al2O3 8-15% by weight -Na2O + K2O 4-16% by weight -CaO + BaO 25-35% by weight -MgO 0-3% by weight -B2O3 0-10% by weight. -
