In addition to atmospheric corrosion resistance, brass also withstands exposure to a wide range of water compositions, including automotive coolant solutions. Brass is generally inert to organic liquids and gases, although it should not be used in mineral acids or acid salts. Alkaline salts are less objectionable. Brass is susceptible to three types of corrosion. These include stress-corrosion cracking, which can arise in ammoniacal environments, amines, mercury compounds and nitrite solutions.
Brasses are perhaps the least susceptible copper alloys to sulfide pitting.
Also, road salt solutions contaminated with sulfide-laden exhaust emissions do not appear to affect brass. Brass can, immersed in acidic and mildly basic waters, corrode by dezincification, but this also has not been a problem in automotive applications. For additional information on corrosion and copper alloys see the Copper Alloy Corrosion Database . Automotive screw machine parts of steel are normally plated with either zinc or cadmium. Chromate conversion coatings, over the electroplate, are also common.