Zn-　and　Pb-rich　deposits　have　been　observed　on　the　waterwall　at　fireside　in　three　tangentially　coal-fired　boilers.　This　work　aims　to　clarify　the　influence　of　ZnS　or　PbS　deposits　on　sulfide　corrosion　behavior　with　the　help　of　field　and　corrosion　testing　analyses.　The　characterization　of　field　samples　shows　that　the　enrichment　of　various　metal　elements　(Pb,　Zn,　Ga,　Se,　etc.)　in　the　corroded　layer　is　mainly　attributed　to　vaporization-condensation　of　metal　vapors,　and　gaseous　migration　of　metal　elements　remained　in　unburnt　char.　In　laboratory　12Cr1MoVG　specimens　were　exposed　to　ZnS　or　PbS　deposits　in　a　mixed　gas　of　0.1%H2S-0.1%O2–5%CO-N2　at　400　or　500　°C　for　120　h.　The　results　show　that　pyrite　is　identified　only　at　400　°C　while　marcasite　appeared　at　500　°C　needs　a　longer　exposure　time.　Iron　can　be　oxidized　in　the　regions　in　which　PbOx　is　stable,　while　in　the　regions　where　PbS　is　stable　iron　can　only　be　sulfided.　PbS　and　ZnS　deposits　could　decrease　the　corrosion　rate　of　specimens.　But　the　capacity　of　PbS　for　hindering　corrosion　attacks　is　slightly　weaker　than　ZnS,　due　to　the　generation　of　Pb(g)　and　more　active　S　migrating　into　corrosion　side.　©　2021　Elsevier　B.V.