PURPOSE: To extend the effective range of rust preventives and to improve the initial corrosion inhibiting power by mixing cyclohexylammonium carbonate (CHC) with benzotriazole (BTA) or tolyltriazole (TTA) in a prescribed ratio.

CONSTITUTION: CHC is mixed with BTA or TTA in (99W80):(1W20) ratio to obtain a volatile rust inhibitor for zinc, etc. The rust inhibitor has a rust inhibiting effect on copper, copper alloys, zinc, other nonferrous metals and alloys thereof as well as iron and iron alloys, so the rust of an assembly composed of different kinds of metals such as iron and copper is inhibited without carrying out disassembly.