Patent Number: 053176103
Section: claims

1. A protective coating for steel in at least part of a system constituting at least one of a wet steam system, a feedwater and condensate system, and a drain system of thermal and nuclear power plants, said system being exposed to a fluid flowing therein, said coating comprising: a a film layer of a material selected from the group consisting of a metal comprising a major component other than Fe and a ceramic, said material being formed on a surface of the system to be protected by a spraying technique selected from the group consisting of atmospheric plasma thermal spraying and high energy plasma thermal spraying so that said film layer is a boundary film chemically stable against said fluid flowing through said system and resistant against the efflux of Fe.sup.2+ to prevent erosion-corrosion of said coated part of said system.  a lower layer coating on said steel of Ni--Cr; and  an upper layer coating of WC+(Ni--Cr), said coatings being formed by atmospheric plasma thermal spraying.  a single layer of elements selected from the group consisting of WC+Co and WC+(Ni--Cr) formed by means of jet kote plasma thermal spraying.  said fluid flowing in said system is deaerated pure water.  said fluid flowing in said system is deaerated pure water.  said fluid flowing in said system is deaerated pure water.  said fluid flowing in said system is deaerated pure water. 2. A coating as claimed in claim 1 comprising: 3. A coating as claimed in claim 1 comprising: 4. A coating as claimed in claim 1 wherein: 5. A coating as claimed in claim 2 wherein: 6. A coating as claimed in claim 3 wherein: 7. A coating as claimed in claim 1 wherein: