DEFEKTI PVD-PREVLEK IN NJIHOV VPLIV NA FIZIKALNO-KEMIJSKE LASTNOSTI SISTEMA PREVLEKA/PODLAGA

Gselman, Peter

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Naslov:	DEFEKTI PVD-PREVLEK IN NJIHOV VPLIV NA FIZIKALNO-KEMIJSKE LASTNOSTI SISTEMA PREVLEKA/PODLAGA
Avtorji:	ID Gselman, Peter (Avtor) ID Zupanič, Franc (Mentor) Več o mentorju...
Datoteke:	DR_Gselman_Peter_2014.pdf (11,88 MB) MD5: BE5CF4595997CF33B66B582F0A3F18E0
Jezik:	Slovenski jezik
Vrsta gradiva:	Doktorska disertacija
Tipologija:	2.08 - Doktorska disertacija
Organizacija:	FS - Fakulteta za strojništvo
Opis:	Trde zaščitne prevleke, izdelane po postopku fizikalnega nanašanja iz parne faze (PVD – angl. physical vapor deposition), so se izkazale za enega izmed najučinkovitejših načinov povečanja produktivnosti odrezovalnih postopkov, vendar njihov potencial še ni popolnoma izkoriščen. Med nanašanjem v njih nastajajo defekti, ki poslabšajo oprijemljivost prevlek na podlago, zmanjšujejo korozijsko obstojnost itd. Kakovost trdih prevlek izboljšamo, če zmanjšamo koncentracijo defektov. To lahko naredimo le, če poznamo mehanizme njihovega nastanka. V disertaciji so opisani mehanizmi nastanka defektov v posameznih stopnjah priprave prevlek in njihov vpliv na fizikalno-kemijske lastnosti sistema prevleka/podlaga. Defekti so bili analizirani v nanoplastni prevleki TiAlN/CrN, ki je bila nanesena na štiri vrste jeklenih podlag (ASP30, M2, D2 in 316L) v naprševalniku s štirimi neuravnoteženimi magnetronskimi izviri. Za preučevanje izvorov, mehanizma nastanka in vpliva defektov PVD-prevlek na fizikalno-kemijske lastnosti sistema prevleka/podlaga so bile uporabljene naslednje tehnike: optični mikroskop (OM), mikroskop na atomsko silo (AFM), vrstični elektronski mikroskop (SEM), fokusiran ionski curek (FIB), presevni elektronski mikroskop (TEM), energijsko-disperzijska spektroskopija (EDS), tribometer, 3D-profilometer in 3D-rekonstrucija iz SEM-posnetkov. Ugotovljeno je bilo, da defekti v prevleki nastanejo predvsem zaradi geometrijskega senčenja, ki ga povzročajo topografske nepravilnosti na površini podlag, delci, ki so po čiščenju ostali na površini, ter delci, ki prispejo na površino podlag med pripravo prevlek (segrevanje, ionsko jedkanje, naprševanje). Kali defektov predstavljajo tudi sulfidni in oksidni nekovinski vključki. Na mestih sulfidnih vključkov v prevleki nastajajo kraterji in pore ne glede na vrsto jeklenih podlag in način jedkanja. Na intenzivno jedkanih oksidnih vključkih v prevleki nastanejo pore, medtem ko na blago jedkanih oksidnih vključkih prevleka raste nemoteno. Najpogostejše topografske nepravilnosti na površini trdih prevlek so nodularni defekti. Ti imajo tudi največji vpliv na povečanje površinske hrapavosti prevleke. Ugotovljeno je bilo tudi, da med tribološkim testom (angl. pin-on-disk) nastanejo prve poškodbe prevleke na mestih nodularnih defektov. Ti defekti so v začetni fazi tribološkega testa glavni vir abrazivnih delcev, ki povzročijo začetek obrabe prevleke. Izkazalo se je, da korozijsko obstojnost sistema prevleka/podlaga poslabšajo le tisti defekti, ki omogočajo elektrolitu prosto pot do podlage.
Ključne besede:	defekti, PVD-prevleka, jamičasta korozija, nekovinski vključki v jeklu
Kraj izida:	[Maribor
Založnik:	P. Gselman]
Leto izida:	2014
PID:	20.500.12556/DKUM-46080
UDK:	621.793:669.058.67:66.019(043.3)
COBISS.SI-ID:	276393984
NUK URN:	URN:SI:UM:DK:P9LG2FLM
Datum objave v DKUM:	30.10.2014
Število ogledov:	3177
Število prenosov:	469
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Področja:	KTFMB - FS
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Sekundarni jezik

Jezik:	Angleški jezik
Naslov:	PVD-DEFECTS AND THEIR INFLUENCE ON PHYSICOCHEMICAL PROPERTIES OF COATING/SUBSTRATE SYSTEM
Opis:	Hard protective coatings prepared by physical vapor deposition (PVD) are one of the most effective ways to increase the machining productivity, but their potential has still not been fully exploited. Growth defects which form in the coating during the deposition process deteriorate the adhesion of coatings to the substrate, reduce the corrosion resistance, etc. Hard coating quality can be improved if growth defects density is reduced. This can be performed by understanding the mechanisms of their origin. In this work, the formation mechanisms of growth defects in each step of coating preparation is described, and their influence on physicochemical properties of the coating/substrate system is evaluated. Growth defects were analysed in TiAlN/CrN nanolayered coating, deposited on four steel types (ASP 30, M2, D2 and 316L) using sputtering system with four unbalanced magnetron sources. To study the origins, the growth mechanisms and the influence of defects on the physicochemical properties of the coating/substrate system, the following analytical techniques were used: optical microscope (OM), atomic force microscope (AFM), scanning electron microscope (SEM), focused ion beam (FIB), transmission electron microscope (TEM), energy-dispersive spectroscopy (EDS), tribometer, 3D profilometer and 3D reconstruction of SEM images. It was found that the growth defects in the coating occur due to geometric shadowing caused by the following seeds: topographic irregularities on the substrate surface, particles which remained on the surface after cleaning, and particles deposited on the surface of substrates during heating, ion etching and sputtering. Sulphite and oxide non-metallic inclusions present in steel are also seeds for growth defects formation. On sulphide inclusion sites in the coating, craters and pores are formed irrespective of the type of steel substrate and plasma etching technique. On intensively etched oxide inclusions, pores form in the coating, while on mild etched oxide inclusions the coating growth is undisturbed. The most common topographic irregularities on the surface of hard coatings are nodular defects. They have the highest influence on the coating surface roughness. It was also found that during the tribological test (pin-on-disk) the first damage of the coating appears on nodular defects. In initial phase of the tribological test these growth defects are the main source of abrasive particles, which causes the beginning of coating wear. It has been shown that the corrosion resistance of the coating/substrate system deteriorates only those growth defects which allow solution to penetrate to the substrate surface.
Ključne besede:	growth defects, PVD-coatings, pitting corrosion, non-metallic inclusion in steels

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