Chromium-free, low-zinc, corrosion-inhibiting pigment mixture (A) comprising (a1) 30% to 60% by weight of at least one calcium hydrogen phosphate pigment, (a2) 15% to 45% by weight of at least one amorphous, calcium-modified silicon dioxide, (a3) 5% to 25% by weight of at least one calcium borosilicate pigment, and (a4) 1% to 15% by weight of at least one zinc salt of an organic nitro compound with the proviso that the zinc content of (A) does not exceed 10% by weight; process for preparing it, and its use.