{"id":6309,"date":"2026-10-19T09:48:45","date_gmt":"2026-10-19T09:48:45","guid":{"rendered":"https:\/\/phd.hi.is\/doktorsvorn\/doktorsvorn-i-velaverkfraedi-gifty-oppong\/"},"modified":"2026-10-19T09:48:45","modified_gmt":"2026-10-19T09:48:45","slug":"doktorsvorn-i-velaverkfraedi-gifty-oppong","status":"publish","type":"phd_defence","link":"https:\/\/phd.hi.is\/en\/doktorsvorn\/doktorsvorn-i-velaverkfraedi-gifty-oppong\/","title":{"rendered":"Doktorsv\u00f6rn \u00ed v\u00e9laverkfr\u00e6\u00f0i &#8211; Gifty Oppong"},"content":{"rendered":"<div class=\"field-items\">\n<div class=\"field-item even\" property=\"content:encoded\">\n<p><a href=\"https:\/\/livestream.com\/hi\/doktorsvorngiftyoppongboakye\"><strong>Streymi<\/strong><\/a><\/p>\n<p><strong>Doktorsefni:<\/strong>\u00a0Gifty Oppong<\/p>\n<p><strong>Heiti ritger\u00f0ar:<\/strong>\u00a0Slit-og n\u00faningseiginleikar og t\u00e6ringarheg\u00f0un h\u00fa\u00f0unarefna fyrir jar\u00f0hitan\u00fdtingu. Tribological Properties and Corrosion Behavior of Coatings for Geothermal Applications<\/p>\n<p><strong>Andm\u00e6lendur: <br \/> <\/strong>Dr. Ralph B\u00e4ssler, fagstj\u00f3ri vi\u00f0 Department of Safety of Structures vi\u00f0\u00a0Bundesanstalt f\u00fcr Materialforschung und -pr\u00fcfung (BAM), \u00de\u00fdskalandi<br \/>Dr. Roy Johnsen, pr\u00f3fessor vi\u00f0 Norwegian University of Science and Technology (NTNU)<\/p>\n<p><strong>Lei\u00f0beinandi:<\/strong>\u00a0Dr. Sigr\u00fan Nanna Karlsd\u00f3ttir<strong>, <\/strong>pr\u00f3fessor vi\u00f0 I\u00f0na\u00f0arverkfr\u00e6\u00f0i-, v\u00e9laverkfr\u00e6\u00f0i- og t\u00f6lvunarfr\u00e6\u00f0ideild H\u00cd<\/p>\n<p><strong>Einnig \u00ed doktorsnefnd: <br \/> <\/strong>Dr. Danyil Kovalov, v\u00edsindama\u00f0ur hj\u00e1 Alsym Energy, Bandar\u00edkjunum<br \/> Dr. Andri Stefansson, pr\u00f3fessor og deildarforseti Jar\u00f0v\u00edsindadeildar H\u00cd<\/p>\n<p><strong>Doktorsv\u00f6rn st\u00fdrir:<\/strong>\u00a0Dr. R\u00fanar Unn\u00fe\u00f3rsson, pr\u00f3fessor og deildarforseti I\u00f0na\u00f0arverkfr\u00e6\u00f0i-, v\u00e9laverkfr\u00e6\u00f0i- og t\u00f6lvunarfr\u00e6\u00f0ideildar H\u00cd<\/p>\n<p><strong>\u00c1grip<\/strong><\/p>\n<p>Aukin eftirspurn \u00e1 heimsv\u00edsu eftir endurn\u00fdjanlegri orku hefur leitt til aukinnar n\u00fdtingar \u00e1 jar\u00f0varmaau\u00f0lindum, sem hefur \u00ed f\u00f6r me\u00f0 s\u00e9r \u00e1skoranir um t\u00e6ringu og slit efna sem notu\u00f0 eru \u00ed n\u00fdtingu jar\u00f0varmans. Markmi\u00f0 doktorsverkefnisins er a\u00f0 rannsaka n\u00faning, slit og t\u00e6ringarheg\u00f0un f\u00e1anlegra og n\u00fdrra h\u00fa\u00f0unarefna sem h\u00f6nnu\u00f0 eru til a\u00f0 b\u00e6ta slit og t\u00e6ringar\u00feol st\u00e1ls sem n\u00fa er nota\u00f0 \u00ed n\u00fdtingu jar\u00f0hita. H\u00fa\u00f0unarefnin sem voru ranns\u00f6ku\u00f0 eru wolframkarb\u00ed\u00f0 (WC) keram\u00edksamsetningar, nikkelmelmi, myndlaust j\u00e1rn-melmi, fj\u00f6lli\u00f0usamsetningur me\u00f0 graf\u00edn-ox\u00ed\u00f0, nikkel-fosf\u00f3r samsetningar og h\u00e1-\u00f3rei\u00f0u-m\u00e1lmbl\u00f6ndur (e. High Entropy Alloys (HEA)). Ni\u00f0urst\u00f6\u00f0urnar s\u00fdndu fram \u00e1 a\u00f0 harka h\u00fa\u00f0unarefnanna haf\u00f0i mikil \u00e1hrif \u00e1 n\u00faning og slit\u00feol, en hr\u00fdfi yfirbor\u00f0sins fl\u00e6kti n\u00faning og renni-heg\u00f0un. Frekari tilraunir \u00ed h\u00e1hita og \u00fer\u00fdstik\u00fat (e. autoclave) leiddi \u00ed lj\u00f3s a\u00f0 slit\u00feolnu h\u00fa\u00f0unarefnin virku\u00f0u sem hindrun gegn t\u00e6ringu \u00ed tilraunaumhverfinu og komu \u00ed veg fyrir t\u00e6ringu \u00e1 undirliggjandi st\u00e1li. Hins vegar voru fr\u00e1vik h\u00e1\u00f0 \u00f6rbyggingu h\u00fa\u00f0unarefnanna, e\u00f0liseiginleikum og efnafr\u00e6\u00f0i tilrauna umhverfisins, sem stu\u00f0la\u00f0i a\u00f0 sta\u00f0bundnum t\u00e6ringar\u00e1hrifum. \u00cd tilraunum vi\u00f0 120\u00b0C \u00ed vatni vi\u00f0 50 bar voru \u00f6ll h\u00fa\u00f0unarefnin verndandi me\u00f0 \u00fev\u00ed a\u00f0 verja undirliggjandi st\u00e1li\u00f0 gegn t\u00e6ringu. En \u00ed tilraunum \u00ed v\u00f6kva-\/gufufasa \u00ed h\u00e6rri hita og auknu t\u00e6randi umhverfi (250 \u00b0C me\u00f0 CO2\/H2S gasi) ur\u00f0u meirihluti h\u00fa\u00f0unarefnanna fyrir anna\u00f0hvort t\u00e6ringarskemmdum \u00ed innri l\u00f6gum, yfirbor\u00f0s\u00fatfellingum e\u00f0a t\u00e6ringu \u00e1 undirliggjandi st\u00e1li. \u00deessi ranns\u00f3kn leiddi einnig \u00ed lj\u00f3s gott t\u00e6ringar\u00feol n\u00fdlegra \u00fer\u00f3a\u00f0s slit\u00feolins HEA h\u00fa\u00f0unarefnis \u00ed \u00f6llum tilraunarumhverfum ranns\u00f3knarinnar og sem hvetur til m\u00f6gulegrar n\u00fdtingar \u00e1 h\u00fa\u00f0unarefninu \u00ed CO2\/H2S-innihaldandi jar\u00f0hitaumverfi. Ni\u00f0urst\u00f6\u00f0urnar gefa g\u00f3\u00f0an grunn sem h\u00e6gt er a\u00f0 byggja \u00e1 til \u00fer\u00f3unar og framlei\u00f0slu \u00ed framt\u00ed\u00f0inni \u00e1 vi\u00f0eigandi t\u00e6ringar- og slit\u00feolnum h\u00fa\u00f0unarefnum fyrir notkun \u00ed jar\u00f0hitaumhverfi vi\u00f0 n\u00fdtingu jar\u00f0hita.<\/p>\n<p><strong>Um doktorsefni\u00f0<\/strong><\/p>\n<p>Gifty Oppong\u00a0 er f\u00e6dd og uppalin \u00ed Ghana. H\u00fan brautskr\u00e1\u00f0ist me\u00f0 BS-gr\u00e1\u00f0u \u00ed efnisverkfr\u00e6\u00f0i fr\u00e1 University of Science and Technology \u00ed Ghana. A\u00f0 n\u00e1mi loknu hlaut h\u00fan Erasmus-sk\u00f3lastyrk til a\u00f0 hefja sameiginlegt meistaran\u00e1m \u00ed yfirbor\u00f0sverkfr\u00e6\u00f0i (surface engineering) vi\u00f0 H\u00e1sk\u00f3lana \u00ed Leeds, Ljubljana, Lule\u00e5 og Coimbra. Gifty h\u00f3f doktorsn\u00e1m sitt vi\u00f0 H\u00cd \u00e1ri\u00f0 2018.<\/p>\n<\/div><\/div>","protected":false},"featured_media":5409,"template":"","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"_phd_date_start":"2022-12-09T13:00:00+00:00","_phd_date_end":"2022-12-09T15:00:00+00:00","_phd_location":"H\u00e1t\u00ed\u00f0arsalur","_phd_admission":"A\u00f0gangur \u00f3keypis","_phd_thesis_title":"Slit-og n\u00faningseiginleikar og t\u00e6ringarheg\u00f0un h\u00fa\u00f0unarefna fyrir jar\u00f0hitan\u00fdtingu. 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