{{Short description|Aggressive solution used to test the resistance of metals to corrosion}} {{refimprove|date=October 2008}} {{use dmy dates|date=May 2025}} {{For|the Doctor Who serial|The Green Death}}

'''Green death''' is a solution used to test the resistance of metals and alloys to corrosion. It consists of a mixture of sulfuric acid, hydrochloric acid, iron(III) chloride and copper(II) chloride and its boiling point is at approximately 103&nbsp;°C. Its typical chemical composition is given in the table hereafter:<ref name="Corrosionpedia">{{Cite web |title=What is Green Death? – Definition from Corrosionpedia |author=Corrosionpedia |work=Corrosionpedia |date=14 November 2016 |access-date=10 September 2021 |url= https://www.corrosionpedia.com/definition/1344/green-death}}</ref><ref name="Haynes">{{Cite web |title=Resistance to pitting and crevice corrosion of Hastelloy C-276 |author=Haynes International |work=Haynesintl.com |date= |access-date=10 September 2021 |url= https://www.haynesintl.com/alloys/alloy-portfolio_/Corrosion-resistant-Alloys/HASTELLOY-C-276-Alloy/resistance-to-pitting-and-crevice-corrosion}}</ref><ref name="Specialmetals">{{Cite web |title=Inconel alloy C-276 |author=Specialmetals.com |work=Specialmetals.com |date= |access-date=10 September 2021 |url= https://www.specialmetals.com/documents/technical-bulletins/inconel/inconel-alloy-c-276.pdf}}</ref><ref name="Mottu">Mottu, Nathalie (2016). URTM66, 02/2016, Industeel ArcelorMittal.</ref> {| class="wikitable" style="text-align:center" |+Chemical composition of the green death solution ! Reagent ! Formula (—) ! Usually (wt.{{nbs}}%) ! Min (wt.{{nbs}}%) ! Max (wt.{{nbs}}%) |- |Sulfuric acid |{{Chem2|H2SO4}} |11.9 |11.5 |11.9 |- |Hydrochloric acid |HCl |1.3 |1.2 |1.3 |- |Iron(III) chloride |{{Chem2|FeCl3}} |1.0 |1.0 |1.0 |- |Copper(II) chloride |{{Chem2|CuCl2}} |1.0 |1.0 |1.0 |}

== Uses == The chemical composition of the green death solution allows it to achieve a particularly aggressive oxidizing chloride solution.<ref name="Corrosionpedia" /> Indeed, among the four reagents, all are oxidizing species ({{Chem2|H2SO4}}, {{Chem2|Fe(3+)}}, {{Chem2|Cu(2+)}}) except hydrochloric acid (HCl) in which the chlorine atom is present in its lowest oxidation state as {{Chem2|Cl-}} anion. The chloride anions, also added to the solution as counter-ions of iron(III) and copper(II) species, are very aggressive for the localized corrosion of metals and alloys as they induce severe pitting corrosion problems. The green death solution is also used to determine the critical pitting temperature (CPT) and the critical crevice temperature (CCT) of metals and alloys.{{cn|date=December 2024}}

== See also == * {{Annotated link|Aqua regia}} * {{Annotated link|Piranha solution}}

==References== {{Reflist}}

Category:Corrosion Category:Oxidizing mixtures Category:Oxidizing acids

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