Utjecaj pH-vrijednosti na koroziju nehrđajućeg čelika za ortopedske pločice

undergraduate thesis

• Title (english): The effect of pH value on stainless steel corrosion for orthopedic plates
• Author: Nikola Kordić
• Mentor: Vera Rede (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2021-09-29, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering

Abstract

Cilj ovog završnog rada bio je analizirati utjecaj pH-vrijednosti na koroziju nehrđajućeg čelika za ortopedske pločice. U teorijskom dijelu rada opisani su biomaterijali s posebnim naglaskom na materijale koji se koriste za izradu ortopedskih implantata.
U eksperimentalnom dijelu rada provedena je analiza kemijskog sastava i analiza mikrostrukture ortopedske pločice od nehrđajućeg čelika. Ispitan je utjecaj pH-vrijednosti 0,9% otopine natrijevog klorida (NaCl) na promjenu mase i na korozijsku postojanost analiziranog čelika.
Analizirana pločica napravljena je od austenitnog nehrđajućeg čelika oznake X2CrNiMo17-12-2, koji u mikrostrukturi sadrži i malu količinu d-ferita. Na rubu poprečnog presjeka pločice izmjerena je mikrotvrdoća od 188 HV0,1, a u sredini 172 HV0,1. Promjena mase pri 60-dnevnom tretiranju uzoraka u otopinama jako varira s promjenom pH-vrijednosti, od prirasta mase kod viših pH-vrijednosti, do gubitka mase kod nižih pH-vrijednosti. Metodom spektrometrije masa uz induktivno spregnutu plazmu (ICP-MS) utvrđeno je da promjena pH-vrijednosti otopine utječe na koncentraciju iona otpuštenih iz čelika. Izmjerena je najveća koncentracija iona željeza, nikla, kroma i molibdena, a nešto manja koncentracija bakra i sumpora. Nije bilo otpuštanja iona Si, P i V.

Abstract (english)

The main aim of the study was to investigate the influence of the pH value on the corrosion of
stainless steel for orthopedic plates. The theoretical part describes biomaterials with special
emphasis on the material used to make orthopedic implants. In the experiment the analysis of
the chemical composition and the analysis of the microstructure of the stainless steel
orthopedic plate was performed. The influence of the pH value of the 0.9% NaCl solution on
the change in mass and on the corrosion resistance of the analyzed steel was explored. The
analyzed plate is made of austenitic stainless steel marked X2CrNiMo17-12-2, which contains
a small amount of d-ferrite in the microstructure. The microhardness of 188 HV0,1 was
measured at the edge of the cross section of the plate, and 172 HV0,1 in the middle. The
change in mass during the 60-day treatment of samples in solution varies greatly with the
change in pH from weight gain at higher pH values to weight loss at lower pH values.
Inductively coupled plasma mass spectrometry (ICP-MS) showed that the change in pH of the
solution affects the concentration of ions released from the steel. The highest concentration of
iron, nickel, chromium, and molybdenum ions, and the slightly lower concentration of copper
and sulfur were measured. There was no release of Si, P, and V ions.

• Keywords: ortopedska pločica; austenitni nehrđajući čelik; pH-vrijednost; masena spektrometrija
• Keywords (english): ortopedic plate; austenitic stainless steel; pH value; mass spectrometry
• Language: croatian
• URN:NBN: urn:nbn:hr:235:129741
• Study programme: Title: Mechanical Engineering; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/ prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka strojarstva (sveučilišni/a prvostupnik/ prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka strojarstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2021-09-27 10:08:46