Analiza emajliranega nerjavnega jekla

magistrsko delo

Mitja Bukovec (Avtor), Matjaž Finšgar (Mentor), Andreja Goršek (Komentor), Tadej Lešer (Komentor)

Povzetek

Magistrsko delo temelji na analizi nerjavnega jekla, ki smo ga prevlekli s štirimi fritami A1, A2, B1 in B2, ki se razlikujejo po svoji sestavi. Kljub temu, da je jeklo nerjavno, lahko v ekstremnih pogojih podleže koroziji, zato smo z elektrokemijskimi metodami dokazali boljšo kemijsko in mehansko odpornost prevlečenega nerjavnega jekla v 5‒odstotni raztopini NaCl pri sobni temperaturi. Pred samim nanašanjem frit smo morali nerjavno jeklo zbrusit, da smo ustvarili pogoje za dobro vezavo emajla na njegovo površino. Brez dobre vezave lahko pride do napak, kot so razpoke, praske, nečistoče, odletavanje emajla itd. Za posamezno frito smo poiskali optimalne pogoje časa in temperaturo žganja. Z talilnim mikroskopom smo ob spreminjanju temperature vizualno spremljali spremembe posamezne frite, kjer so nas zanimale točke sintranja, zmehčanja, polkrogle in stekanja. S postopkom dilatometrije smo merili razteznostni koeficient posameznega emajla, ter ga primerjali z razteznostnim koeficientom nerjavnega jekla, ker mora biti razteznostni koeficient emajla prilagojen koeficientu podlage, drugače pride do napak. Pri posamezni friti smo izbrali najboljši in najslabši vzorec, ter ga primerjali z vzorcem brez prevleke. Za elektrokemijsko testiranje smo uporabili različne tehnike, kot so kronopotenciometrija, impedančna spektroskopija in ciklična polarizacija. Ugotovili smo, da je vzorec brez prevleke napadla korozija in tak vzorec več nima možnosti repasivacije. Na drugi strani pa smo za vse štiri frite dobili odlične rezultate. Ugotovili smo, da noben vzorec nerjavnega jekla, ki je bil prevlečen s frito, ni podlegel koroziji. Najbolj odporna od vseh, pa je frita A1.

Ključne besede

frite;emajl;nerjavno jeklo;emajliranje;elektrokemija;magistrske naloge;

Podatki

Jezik:	Slovenski jezik
Leto izida:	2016
Tipologija:	2.09 - Magistrsko delo
Organizacija:	UM FKKT - Fakulteta za kemijo in kemijsko tehnologijo
Založnik:	[M. Bukovec]
UDK:	669.14.018.8(043.2)
COBISS:	20334102
Št. ogledov:	1716
Št. prenosov:	134
Ocena:	0 (0 glasov)
Metapodatki:

Ostali podatki

Sekundarni jezik:	Angleški jezik
Sekundarni naslov:	ANALYSIS OF THE ENAMELED STAINLESS STEEL
Sekundarni povzetek:	Master's thesis is based on an analysis of the stainless steel. We coated the steel with four frits A1, A2, B1 and B2, that differed in their composition. Despite the fact that the steel is stainless, in extreme conditions it can succumb to corrosion, therefore electrochemical methods demonstrated better chemical and mechanical resistance of the coated stainless steel to give a 5 percent solution of NaCl at room temperature. Prior to applying frit we have stainless steel whet so that the conditions for good adhesion to the enamel surface were met. Without good bonding errors such as cracks, scratches, dirt, breaking away of the enamel, etc. Could occur. For each frit we found the optimal conditions of time and temperature spirits. With a melt microscope we changed the temperature of the visual track changes in individual frits where we were interested in points of sintering, softening, hemispherical and depositing. The procedure of dilatometry measured expansion coefficient of each enamel, and compared it with the expansion coefficient of stainless steel, whereas the coefficient of expansion coefficient must be abjusted tp the enamel adjusted basis, otherwise errors may occur. In each frit we chose the best and worst sample and compared it with the model without the cover. For electrochemical testing, we used a variety of techniques such as chronopotentiometry, impedance spectroscopy and cyclic polarization. We found that the uncoated pattern was attacked by corrosion and such a pattern did not have more rapidity opportunity. On the other hand, we got excellent results for all four frits tested. We have found that each sample of stainless steel that has been coated with a plate, did not succumb to corrosion. The most resistant of all was the frit A1.
Sekundarne ključne besede:	frits;enamel;stainless steel;enamelling;electrochemistry;
URN:	URN:SI:UM:
Vrsta dela (COBISS):	Magistrsko delo/naloga
Komentar na gradivo:	Univ. v Mariboru, Fak. za kemijo in kemijsko tehnologijo
Strani:	X, 68 f.
ID:	9160747