Visokotemperaturne tribološke lastnosti večplastnih zaščitnih prevlek iz (Cr,V)N : magistrsko delo

Korbar, Domen (author), Nagode, Aleš (mentor), Drnovšek, Aljaž (comentor)

V magistrskem delu smo raziskovali večplastne trde zaščitne prevleke CrN/(Cr,V)N/VN, ki smo jih pripravili s postopkom fizikalnega nanašanja iz parne faze. Namen magistrskega dela je bil analizirati vpliv deleža vanadija na mikrostrukturo, mehanske lastnosti ter visokotemperaturno tribološko obnašanje nanešenih večplastnih prevlek. Večplastne prevleke smo pripravili z magnetronskim naprševanjem, pri čemer smo uporabili dve segmentni tarči Cr/V ter po eno tarčo iz kroma in vanadija. Z uporabo segmentnih tarč ter namestitvijo vzorcev na različne višine v vakuumski komori je bilo mogoče v enem samem procesu pripraviti prevleke z različnimi deleži vanadija in kroma. Po nanosu smo debelino prevleke določili z uporabo krogelnega obrusa, medtem ko smo za karakterizacijo topografije uporabili kontaktni profilometer in mikroskop na atomsko silo. Mehanske lastnosti po nanosu smo določili z nanoindentacijo, tribološke lastnosti pa smo analizirali pri sobni temperaturi ter pri povišanih temperaturah 300, 600 in 700 °C. Kristalno strukturo prevleke smo preučili z rentgensko uklonsko analizo tako po nanosu, kot tudi po visokotemperaturnih triboloških preizkusih. Rezultati so pokazali, da se delež vanadija v prevleki linearno zmanjšuje z višino vzorca na nosilcu v vakuumski komori. Deleža vanadija v prevleki je pomembno vplival na skupno debelino nanešene večplastne prevleke, ki se je z višanjem vsebnosti vanadija zmanjševala, pri čemer so se sočasno spreminjale tudi njene topografske značilnosti. Višji delež vanadija je tudi vplival na povečanje mrežnega parametra in na kristalografsko orientacijo prevleke. Prav tako pa so se z dodatkom vanadija izboljšale mehanske lastnosti prevleke. Tribološki preizkusi so pokazali, da se je z višanjem temperature koeficient trenja zmanjšal, predvsem zaradi tvorbe mazalne Magnélijeve faze V2O5. Čeprav se je izkazalo, da delež vanadija sam po sebi nima odločilnega vpliva na koeficienta trenja, pa ima pomemben vpliv na stabilnost prevleke pri visokotemperaturni tribologiji.

• Language: Slovenian
• Keywords: Trde zaščitne prevleke, PVD, (Cr, V)N, večslojne prevleke, visokotemperaturna tribologija
• Work type: Master's thesis/paper
• Organization: NTF - Faculty of Natural Sciences and Engineering
• Year: 2025
• PID: 20.500.12556/RUL-172069
• COBISS.SI-ID: 255958019
• Publication date in RUL: 05.09.2025

Secondary language

• Language: English
• Title: High-temperature tribology of multilayered (Cr,V)N protective coatings : master's thesis

Abstract

In this master's thesis, we investigated multilayer hard protective coatings of the type CrN/(Cr,V)N/VN, deposited using the physical vapor deposition technique. The aim of the thesis was to analyse the effect of vanadium content on the microstructure, mechanical properties, and high-temperature tribological behaviour of the deposited multilayer coatings. The multilayer coatings were prepared by magnetron sputtering, using two segmented Cr/V targets and one target each of chromium and vanadium. By employing segmented targets and placing the samples at different heights within the vacuum chamber, it was possible to produce coatings with varying vanadium and chromium contents within a single deposition process. After deposition, the coating thickness was determined using a ball cratering method, while surface topography was characterized using a contact profilometer and an atomic force microscope. The mechanical properties after deposition were evaluated by nanoindentation, while the tribological properties were analysed at room temperature and at elevated temperatures of 300, 600, and 700 °C. The crystal structure of the coatings was examined using X-ray diffraction, both after deposition and following high-temperature tribological testing. The results showed that the vanadium content in the coating decreases linearly with the sample height on the holder in the vacuum chamber. The vanadium content in the coating significantly affected the overall thickness of the multilayer coating, which decreased with increasing vanadium content, accompanied by simultaneous changes in its topographical features. A higher vanadium content also contributed to an increase in the lattice parameter and influenced the crystallographic orientation of the coating. Furthermore, the addition of vanadium improved the mechanical properties of the coating. Tribological tests demonstrated that the coefficient of friction decreased with increasing temperature, primarily due to the formation of the lubricious Magnéli phase V2O5. Although it was found that the vanadium content itself does not have a decisive effect on the coefficient of friction, it plays an important role in enhancing the coating’s stability under high-temperature tribological conditions.

• Keywords: Hard protective coatings, PVD, (Cr, V)N, multilayer coatings, high temperature tribology