Abstract
Two cases are presented on improvement in corrosion resistance by alloying design for equipments related to energy systems. Metal dusting, which is often encountered in CO containing gas environments, is a prominent corrosion problem for the equipment of GTL (gas to liquid) process.The resistance to the metal dusting is remarkably increased by Cu addition to a Ni-base alloy in addition to the high Cr content for the formation of the protective oxide film which acts as a barrier against the CO gas, because the added Cu, which is prone to segregate on the alloy surface, prevents dissociation of the adsorbed CO molecule and therefore the C entry at the defect sites of the oxide film.
Highly pressurized hydrogen is one of the most effective media for storage and transport of hydrogen for fuel cells. However, the pressurized hydrogen causes various materials to suffer hydrogen environment embrittlement (HEE). The susceptibility to the HEE of 300 series of austenitic stainless steels largely depends on the degree of deformation-induced martensitic transformation at the crack tip. Therefore, the high resitance to the HEE is obtained by the alloying design which minimizes its transformation in the austenitic stainless steels.
