Nitrate stress corrosion, metals

LEAD DICHLORIDE (7758-95-4) CljPb Noncombustible solid. A reducing agent. Reacts, possibly violently, with strong oxidizers. Contact with acids or acid fumes produces highly toxic chloride fumes. Incompatible with calcium (mixture is explosive in presence of heat). Forms heat-or shock-sensitive explosive mixtures with ammonium nitrate. Attacks metals in the presence of moisture and may cause pitting and stress corrosion in austenitic stainless steels. 

Flis J. (1991). Stress corrosion cracking of structural steels in nitrate solutions. In Corrosion of Metals and Hydrogen-Related Phenomena. Materials Science Monograph, Vol. 59 (ed. J Flis). Amsterdam Elsevier, pp. 57-94. 

Stress corrosion cracking in alkali-metal hydroxide solutions shows a number of variations. Whereas in nitrate solntions the grain bonndary breakthrough potential only means a restriction of... 

In addition to the known corrosive effects of alkali-metal hydroxide and nitrate solutions, intergranular stress corrosion cracking in unalloyed and low-alloy steels in contact with ammonium carbonate and crude methanol (methanol with low concentration of impurities) has also been observed (Matsukura and Sato 1977 Wendler-Kalsch 1983). When this group of materials comes into contact with various othCT aggressive substances, stress corrosion cracking occurs, primarily with transgranular characteristics. 

Embrittlement embrittlement and for improperly heat treated steel, both of which give intergranular cracks. (Intercrystalline penetration by molten metals is also considered SCC). Other steels in caustic nitrates and some chloride solutions. Brass in aqueous ammonia and sulfur dioxide. physical environments. bases of small corrosion pits, and cracks form with vicious circle of additional corrosion and further crack propagation until failure occurs. Stresses may be dynamic, static, or residual. stress relieve susceptible materials. Consider the new superaustenitic stainless steels. 

HalicteSCC of Ti-811 in methanol accelerates with halo-gen/halide additions. Water additions have an in-hibitive effect, and numerous species have been found that inhibit transgrantilar (Stage II) stress cracking in methanol depending on halide level. These include nitrate and sulfate ions, NaF, and O.IM concentrations of Al, Zr" ", Cd , and Sn" " metallic ions Corrosion, Vol 27,1971, p 46-48). Investigators have also demonstrated that titanium alloy SCC in neutral methanol/halide solutions can be fully arrested by appHed cathodic potentials of—1.0 to —1.5 V (SCE). 

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