Abstract: An anti-corrosive composition, comprising a combination of at least two of the following materials: vanadates, molybdates, tungstates, silicates, phosphates, borates, Ce cations, Y cations, La cations, Eu cations, Gd cations, Nd cations, and reaction products thereof.

Abstract: The invention provides chromate-free coating mixtures, and coatings formed from these mixtures, that protect an underlying aluminum or aluminum alloy substrate from corrosion. The coating mixtures include a continuous phase selected from organic polymeric compositions, or sol-gels, and a distributed phase, dispersed or dissolved throughout the continuous phase. The distributed phase includes the corrosion-inhibiting chromate-free salts. In accordance with the invention, the mixture of salts includes (1) a first salt selected from (a) the esters of rare earth metals, such as cerium and lanthanum oxalates and acetates, and (b) the vanadate salts of alkali and alkali earth metals, such as sodium metavanadate and calcium metavanadate; and (2) a second salt that is a borate salt of alkali earth metals, such as barium metaborate. In certain embodiments, the coatings of the invention include both (a), and (b), in conjunction with the borate salt (2).

Abstract: An in situ sensor for monitoring the degree of corrosion of rebar in a concrete structure relies on a four-point resistance measure of a test wire embedded in the concrete structure. The resistance across the wire is compared with the resistance of a reference wire, which is corrosion resistant. As corrosion advances, the cross-sectional area of the wire decreases, effectively increasing the resistance measured. The sensor may be used to measure corrosion inhibitor performance, and the effect of dilution.

Abstract: The invention provides chromate-free coating mixtures, and coatings formed from these mixtures, that protect an underlying aluminum or aluminum alloy substrate from corrosion. The coating mixtures include a continuous phase selected from organic polymeric compositions, or sol-gels, and a distributed phase, dispersed or dissolved throughout the continuous phase. The distributed phase includes the corrosion-inhibiting chromate-free salts. In accordance with the invention, the mixture of salts includes (1) a first salt selected from (a) the esters of rare earth metals, such as cerium and lanthanum oxalates and acetates, and (b) the vanadate salts of alkali and alkali earth metals, such as sodium metavanadate and calcium metavanadate; and (2) a second salt that is a borate salt of alkali earth metals, such as barium metaborate. In certain embodiments, the coatings of the invention include both (a), and (b), in conjunction with the borate salt (2).