Korozijske lastnosti cirkonija v umetni slini z dodatkom organskih in ortofosforne kisline

diplomsko delo visokošolskega strokovnega študijskega programa I. stopnje

Laura Kobe Stožinič (Avtor), Mojca Slemnik (Mentor), Matjaž Kristl (Komentor)

Povzetek

Zaradi vse pogostejše uporabe cirkonijevih implantatov, je bil namen diplomske naloge raziskati korozijske lastnosti cirkonija v umetni slini z dodatkom organskih in ortofosforne kisline. Osnovna raztopina, ki je služila kot agresivni medij, je bila umetna slina v prisotnosti najpogostejših kislin, ki jih vnašamo v ustno votlino s hrano in pijačo. Kisline, ki smo jih glede na priporočene dnevne vnose dodajali umetni slini, so bile različne organske: vinska, jabolčna in mlečna ter ortofosforna kislina. Eksperimentalni del smo izvedli z gravimetrično metodo, pri temperaturi 37 °C, kar je optimalna telesna temperatura človeka in pri atmosferskem tlaku 101,3 kPa, na ta način smo se čim bolj približali pogojem v ustni votlini. Pred samim postopkom gravimetrije smo pripravili raztopino umetne sline s preračunanimi količinami organskih in ortofosforne kisline. Sam postopek gravimetrije je vključeval naslednje korake: vzorce, ki smo jih termostatirali smo predhodno ustrezno pripravili, kar je zajemalo postopke brušenja, poliranja, razmastitve, ultrazvočnega čiščenja in sušenja s komprimiranim zrakom. Tako pripravljene vzorce smo stehtali in termostatirali v raztopinah 24, 48, 72 in 96 h. Po pretečenem času smo korodirane vzorce ponovno ustrezno očistili in stehtali. Na podlagi spremembe mase vzorca pred in po izpostavitvi raztopini smo izračunali korozijsko hitrost. Tako smo ugotovili, katera kislina povzroča največje korodiranje cirkonija oziroma v kateri kislini je cirkonij najbolj odporen in tvori stabilen pasivni film. Z vrstičnim elektronskim mikroskopiranjem smo posneli površine nekaterih vzorcev. Po 24, 48, 72 in 96 urni pasivaciji, so rezultati pokazali, da na spološno cirkonij tvori najbolj stabilen pasivni film v raztopini umetne sline z dodatkom jabolčne kisline. Najmanj odporen je v raztopini umetne sline z dodatkom mlečne kisline do 48 ur pasivacije, po 48 urah pa korozijske hitrosti cirkonija v raztopini umetne sline z dodatkom mlečne kisline padajo, medtem, ko v raztopini umetne sline z dodatkom vinske kisline naraščajo. Izračunane korozijske hitrosti so v splošnem nizke, kar pomeni, da je cirkonij v kovinski obliki glede korozije primeren material za medicinske vsadke.

Ključne besede

cirkonij;umetna slina;dentalni implantati;korozija;organske kisline;ortofosforna kislina;diplomske naloge;

Podatki

Jezik:	Slovenski jezik
Leto izida:	2024
Tipologija:	2.11 - Diplomsko delo
Organizacija:	UM FKKT - Fakulteta za kemijo in kemijsko tehnologijo
Založnik:	[L. Kobe Stožinič]
UDK:	620.193.47:669.296(043.2)
COBISS:	216343811
Št. ogledov:	63
Št. prenosov:	13
Ocena:	0 (0 glasov)
Metapodatki:

Ostali podatki

Sekundarni jezik:	Angleški jezik
Sekundarni naslov:	Corrosion properties of zirconium in artificial saliva with addition of organic and orthophosphoric acids
Sekundarni povzetek:	Due to the increasing use of zirconium implants, the aim of the thesis was to investigate the corrosion properties of zirconium in artificial saliva with the addition of organic and orthophosphoric acids. The basic solution used as corrosion medium was therefore artificial saliva in the presence of the most common acids introduced into the oral cavity by food and drink. The acids added to the artificial saliva according to the recommended daily intakes were various organic acids: tartaric, malic, lactic and orthophosphoric acids. The experimental part was carried out using the gravimetric method, at a temperature of 37 °C, which is the optimum body temperature for humans, and at an atmospheric pressure of 101,3 kPa, in order to approximate as closely as possible the conditions in the oral cavity. Prior to the gravimetric procedure, an artificial saliva solution was prepared with calculated amounts of organic and orthophosphoric acid. The gravimetric procedure itself involved the following steps: the samples to be thermostatted were properly prepared beforehand, which included grinding, polishing, degreasing, ultrasonic cleaning and compressed air drying. The samples thus prepared were weighed and thermostated in solutions for 24, 48, 72 and 96 h. After the elapsed time, the corroded samples were again cleaned and weighed accordingly. The corrosion rate was calculated from the change in mass of the sample before and after exposure to the solution. This allowed us to determine which acid causes the most corrosion of zirconium or in which acid zirconium is most resistant and forms a stable passive film. After 24, 48, 72 and 96 h of passivation, the results showed that, overall, zirconium forms the most stable passive film in the solution of artificial saliva with the addition of malic acid. It is the least resistant in a solution of artificial saliva with the addition of lactic acid up to 48 h of passivation. After 48 h of passivation, the corrosion rates of zirconium in a solution of artificial saliva with the addition of lactic acid decrease, while in a solution of artificial saliva with the addition of tartaric acid they increase. The calculated corrosion rates are generally low, which means that zirconium in metallic form is a suitable material for medical implants in terms of corrosion.
Sekundarne ključne besede:	zirconium;artificial saliva;dental implants;corrosion;organic acids;orthophosphoric acid;
Vrsta dela (COBISS):	Diplomsko delo/naloga
Komentar na gradivo:	Univ. v Mariboru, Fak. za kemijo in kemijsko tehnologijo
Strani:	1 spletni vir (1 datoteka PDF (VIII, 35 f.))
ID:	24778998