[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"detail-sidebar-cat-0-en-105":3,"doc-seo-657117-105":59,"doc-detail-657117-en":124},{"code":4,"msg":5,"data":6},0,"success",[7,13,18,23,28,33,38,43,48,51,55],{"id":8,"doc_module":4,"doc_module_name":9,"category_name":10,"show_sort_weight":11,"slug":12},1,"Document","Story & Novel",90,"story-novel",{"id":14,"doc_module":4,"doc_module_name":9,"category_name":15,"show_sort_weight":16,"slug":17},2,"Literature",80,"literature",{"id":19,"doc_module":4,"doc_module_name":9,"category_name":20,"show_sort_weight":21,"slug":22},4,"Exam",70,"exam",{"id":24,"doc_module":4,"doc_module_name":9,"category_name":25,"show_sort_weight":26,"slug":27},5,"Comic",60,"comic",{"id":29,"doc_module":4,"doc_module_name":9,"category_name":30,"show_sort_weight":31,"slug":32},6,"Technology",50,"technology",{"id":34,"doc_module":4,"doc_module_name":9,"category_name":35,"show_sort_weight":36,"slug":37},7,"Healthcare",40,"healthcare",{"id":39,"doc_module":4,"doc_module_name":9,"category_name":40,"show_sort_weight":41,"slug":42},8,"Research & Report",30,"research-report",{"id":44,"doc_module":4,"doc_module_name":9,"category_name":45,"show_sort_weight":46,"slug":47},9,"Religion & Spirituality",20,"religion-spirituality",{"id":46,"doc_module":4,"doc_module_name":9,"category_name":49,"show_sort_weight":46,"slug":50},"World Cup","world-cup",{"id":52,"doc_module":4,"doc_module_name":9,"category_name":53,"show_sort_weight":52,"slug":54},10,"Lifestyle","lifestyle",{"id":56,"doc_module":4,"doc_module_name":9,"category_name":57,"show_sort_weight":24,"slug":58},19,"General","general",{"code":4,"msg":60,"data":61},"ok",{"site_id":62,"language":63,"slug":64,"title":65,"keywords":66,"description":67,"schema_data":68,"social_meta":117,"head_meta":119,"extra_data":121,"updated_unix":123},105,"en","pourbaix-diagram-corrosion-states-and-diagram-interpretation","Pourbaix diagram - Corrosion states and diagram interpretation","","Pourbaix (potential–pH) diagrams describe how the thermodynamic stability of a metal depends on electrode potential and pH. They plot redox potential versus pH and distinguish equilibrium regions for immunity, corrosion (active state), and passivity (formation of inhibiting passive layers). Constructed from Nernst-equation and solubility calculations, they support assessing reaction directions and corrosion-product compositions, and they show environmental pH–potential changes that reduce or prevent corrosion. Rates are not directly determined from the diagrams.",{"@graph":69,"@context":116},[70,84,99],{"@type":71,"itemListElement":72},"BreadcrumbList",[73,77,79,82],{"item":74,"name":75,"@type":76,"position":8},"https://docshare.wps.com","Home","ListItem",{"item":78,"name":9,"@type":76,"position":14},"https://docshare.wps.com/document/",{"item":80,"name":35,"@type":76,"position":81},"https://docshare.wps.com/document/healthcare/",3,{"item":83,"name":65,"@type":76,"position":19},"https://docshare.wps.com/document/pourbaix-diagram-corrosion-states-and-diagram-interpretation/657117/",{"url":83,"name":65,"@type":85,"author":86,"headline":65,"publisher":89,"fileFormat":92,"inLanguage":63,"description":67,"dateModified":93,"datePublished":93,"encodingFormat":92,"isAccessibleForFree":94,"interactionStatistic":95},"DigitalDocument",{"name":87,"@type":88},"vwvw","Person",{"url":74,"name":90,"@type":91},"DocShare","Organization","application/pdf","2026-10-26",true,{"@type":96,"interactionType":97,"userInteractionCount":4},"InteractionCounter",{"@type":98},"ViewAction",{"@type":100,"mainEntity":101},"FAQPage",[102,108,112],{"name":103,"@type":104,"acceptedAnswer":105},"What do Pourbaix diagrams represent in corrosion analysis?","Question",{"text":106,"@type":107},"They represent the thermodynamic stability of a metal as a function of electrode potential and pH, allowing identification of stability regions.","Answer",{"name":109,"@type":104,"acceptedAnswer":110},"What are the three metal states described for aggressive media?",{"text":111,"@type":107},"Corrosion (active state), passivity (formation of passive layers that inhibit corrosion), and immunity (thermodynamic stability).",{"name":113,"@type":104,"acceptedAnswer":114},"Can corrosion rates be derived directly from Pourbaix diagrams?",{"text":115,"@type":107},"No. The diagrams indicate stability regions, but actual corrosion rates cannot be derived from them.","https://schema.org",{"og:url":83,"og:type":118,"og:title":65,"og:site_name":90,"og:description":67},"article",{"robots":120,"canonical":83},"index,follow",{"doc_id":122,"site_id":62},657117,1792974442,{"code":4,"msg":5,"data":125},{"doc_id":122,"user_id":126,"nickname":87,"user_avatar":127,"doc_module":4,"category_id":34,"category_name":35,"doc_title":65,"doc_description":67,"doc_content":128,"file_id":129,"file_url":130,"file_type":131,"file_size":132,"view_count":4,"is_deleted":4,"is_public":8,"is_downloadable":8,"audit_status":8,"page_count":24,"language":133,"language_code":63,"site_id":62,"html_lang":63,"table_of_contents":134,"faqs":135,"seo_title":136,"seo_description":67,"update_tm":123,"read_time":137},3985747874149,"https://ap-avatar.wpscdn.com/avatar/3a001161165b4dc3d9e?x-image-process=image/resize,m_fixed,w_180,h_180&k=1790129441039064114","Pourbaix diagram (stability diagram)  \nPotential-pH diagrams are also called Pourbaix diagrams after the name of their originator, Pourbaix (1963), a Belgium electrochemist and corrosion scientist. These diagrams represent the stability of a metal as a function of potential and [pH. at](pH. at) a particular combination of pH and potential, a stable phase can be determined from the Pourbaix diagram. In such diagrams, the redox potential of the corroding system is plotted on a vertical axis and the pH on a horizontal axis. These diagrams are constructed from calculations based on Nernst equations and solubility data for metal and its species, such as Fe, Fe 2 O 3 , Fe(OH) 2 , Fe 3 O4 , etc in equilibrium. And we can identify the stability region (immunity, corrosion, and passivity), however these are only indications ;actual rates cannot be derived from the diagrams.  \nThe information in the diagrams can be beneficially used to control corrosion of pure metals in the aqueous environment. By altering the pH and potential to the regions of immunity and passivation, corrosion can be controlled.  \nThus, Pourbaix diagrams introduce the concept of the following three states of metals, depending on the potential in the given aggressive medium and the determination of its corrosion behavior: corrosion (active state), passivity (forming passive layers inhibiting the corrosion process on the surface of the metal, including thermodynamically active metals) and immunity (thermodynamic stability) of the metals. Further, it will be shown that these three metal states in aggressive media have a special value when corrosion action by an external current on the metal is considered and when methods and means of protection from electrocorrosion are developed.  \nCharacteristics of a Pourbaix Diagram  \n1-pH is plotted on the horizontal axis and redox potential E vs. SHE on the horizontal axis.  \n2-The horizontal lines represent electron transfer reactions. They are pH-independent, but potential-dependent.  \n3-The vertical lines are potential-independent but pH-dependent and not accompanied by any electron transfer.  \n4-The sloping, straight lines give the redox potentials of a solution in equilibrium with hydrogen and oxygen, respectively. This equilibrium indicates electron transfer as well as pH.  \n5-The concentration of all metal ions is assumed to be 10-6 mol per liter of solution. At lower concentration, corrosion should not occur.  \n6-The diagram is computed for the equilibrium conditions at 25°C.  \n7-The upper end of the redox potential axis is the noble end and the lower end, the active end, meaning that the oxidizing power increase with increasing potential.  \n8-The hydrogen and oxygen lines are indicated in Pourbaix diagrams by dotted line.  \nThe main objectives ofthe Pourbaix diagrams are:  \n1. To show the directions ofthe various reactions at given pH and potential.  \n2. To make a basis for estimation of the corrosion product compositions at various pH and potential combinations.  \n3. To show which environmental pH and potential changes will reduce or prevent corrosion.  \nPourbaix for water  \nEach line of a Pourbaix diagram represents conditions of thermodynamic equilibrium for some reaction. The Pourbaix diagram for water is presented in below figure, above line b, oxygen is evolved in accord with the reaction  \n12 O2 􀀎 2H 􀀎 􀀎 2e 􀀐 􀁯 H2 O  \nBy use the Nernst equation we can write relationship between potential and pH as below  \nE 􀀠 E 􀀤 􀀐 2.303 ~~ ~~RTzF~~ ~~ log ~~ 􀀾~~H~~ 􀁀~~2~~ ~~  \nWith E○=1 .299 volt, T=298 ○K, R=8 . 134 J/ ○K. mol and F=96500 C/ mol we have  \nE 􀀠 1.299 􀀐 0.0592 pH  \nAbove line b, defined by this equation, oxygen is evolved at the surface of an immersed electrode. Below this line, water is stable. Below line a, hydrogen is evolved in accord with the reaction : 2H 􀀎 􀀎 2e 􀀐 􀁯 H2  \nUsing the Nernst equation for this equilibrium, the relationship between potential and pH is  \nE 􀀠 E 􀀤 􀀐 2.303 ~~ ~~RTzF~~ ~~ log ~~ 􀀾~~H~~ ","cbCaiqsGb1x9Wwl0","https://ap.wps.com/l/cbCaiqsGb1x9Wwl0","pdf",272064,"English","# Characteristics of a Pourbaix Diagram\n## Pourbaix for water\n## Pourbaix for iron","[{\"question\":\"What do Pourbaix diagrams represent in corrosion analysis?\",\"answer\":\"They represent the thermodynamic stability of a metal as a function of electrode potential and pH, allowing identification of stability regions.\"},{\"question\":\"What are the three metal states described for aggressive media?\",\"answer\":\"Corrosion (active state), passivity (formation of passive layers that inhibit corrosion), and immunity (thermodynamic stability).\"},{\"question\":\"Can corrosion rates be derived directly from Pourbaix diagrams?\",\"answer\":\"No. The diagrams indicate stability regions, but actual corrosion rates cannot be derived from them.\"}]","Pourbaix diagram - Corrosion states and diagram interpretation | PDF",13]