Utjecaj inhibitora na korozijsko ponašanje X37CrMoV5-1 alatnog čelika za topli rad u mediju 3,5 % NaCl

master's thesis

• Title (english): The effect of the inhibitor on the corrosion behavior of X37CrMoV5-1 hot work tool steel in a medium OF 3,5 % NaCl
• Author: Marija Pernar
• Mentor: Anita Begić Hadžipašić (mentor)
• Mentor: Sandra Brajčinović (komentor)
• Committee member: Ljerka Slokar Benić (predsjednik povjerenstva)
• Committee member: Stjepan Kožuh (član povjerenstva)
• Committee member: Natalija Dolić (član povjerenstva)
• Committee member: Anita Begić Hadžipašić (član povjerenstva)
• Committee member: Sandra Brajčinović (član povjerenstva)
• Granter: University of Zagreb; Faculty of Metallurgy; Sisak
• Defense date and country: 2024-09-30, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Metallurgy

Abstract

U ovom radu provedena su elektrokemijska i metalografska ispitivanja X37CrMoV5-1 alatnog čelika za topli rad interne oznake UTOPMO1 s ciljem procjene njegove otpornosti na koroziju u kloridnom mediju s i bez dodatka inhibitora. Tafelovom ekstrapolacijom polarizacijskih krivulja dobivena je manja brzina korozije ispitanog alatnog čelika u 3,5 % otopini NaCl s dodatkom inhibitora, što potvrđuje učinkovitost inhibitora VCI 379/611 u smanjenju brzine korozije. Elektrokemijskom impedancijskom spektroskopijom dobiveni su parametri impedancije, pri čemu je registriran veći otpor prijenosu naboja alatnog čelika u 3,5 % otopini NaCl s dodatkom inhibitora, što upućuje na činjenicu da se adsorbiranjem inhibitora na površini uzorka stvorio deblji oksidni sloj, koji štiti čelik od daljnjeg prodiranja agresivnih kloridnih iona iz otopine. Mikrostruktura ispitanog čelika je sitnozrnata te u osnovi martenzitna s jednolikom raspodjelom karbida, čime se postiže bolja korozijska otpornost. Metalografska ispitivanja su potvrdila navedene rezultate elektrokemijskih ispitivanja, jer su registrirani izraženiji korozijski produkti na uzorku izloženom 3,5 % otopini NaCl bez dodatka inhibitora.

Abstract (english)

In this work, electrochemical and metallographic tests of X37CrMoV5-1 hot work tool steel designated as UTOPMO1 were carried out with the aim of evaluating its corrosion resistance in a chloride medium with and without the addition of inhibitor. By Tafel extrapolation of the polarization curves, a lower corrosion rate of the tested tool steel was obtained in a 3,5 % NaCl solution with the addition of an inhibitor, which confirms the effectiveness of the VCI 379/611 inhibitor in reducing the corrosion rate. Impedance parameters were obtained by electrochemical impedance spectroscopy, where a higher charge transfer resistance of the tool steel was registered in a 3.5% NaCl with the addition of an inhibitor, which points to the fact that adsorbing the inhibitor created a thicker oxide layer on the surface of the sample, which protects the steel from further penetration of aggressive chloride ions from the solution. The microstructure of the tested steel is fine-grained and basically martensitic with a uniform distribution of carbides, which achieves better corrosion resistance. Metallographic tests confirmed the stated results of electrochemical tests, as more pronounced corrosion products were registered on the sample exposed to a 3,5 % NaCl solution without the addition of inhibitors.

• Keywords: alatni čelik za topli rad; 3; 5 % NaCl; inhibitor; brzina korozije; impedancija; mikrostruktura
• Keywords (english): hot work tool steel; 3.5 % NaCl; inhibitor; corrosion rate; impedance; microstructure
• Language: croatian
• URN:NBN: urn:nbn:hr:115:982120
• Study programme: Title: University graduate study program Metallurgy; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka metalurgije (magistar/magistra inženjer/inženjerka metalurgije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2024-09-20 09:54:22