Toplotne lastnosti emajlov in emajlirane pločevine

Ferčak, Žan (author), Karpe, Blaž (mentor)

V sklopu diplomskega dela smo z metodo tranzientnega planarnega toplotnega vira (Hot Disk TPS 2200) v skladu z mednarodnim standardom ISO 22007 opravili meritve toplotnih lastnosti dveh vrst emajlov, ki se uporabljata v industriji bele tehnike. Ker direktnih meritev toplotnih lastnosti emajlirane jeklene pločevine nismo mogli izvesti, smo vzorce emajlov pripravili tudi v obliki debelih plasti. Rezultati, ki smo jih pridobili z meritvami toplotnih lastnosti debelih plasti, so v okviru pričakovanih vrednosti za toplotne lastnosti emajlov, ugotavljamo pa, da ima velik vpliv na toplotne lastnosti dosežena gostota emajlirane plasti. Vzorce emajlirane pločevine smo metalografsko pripravili in analizirali z vrstično elektronsko mikroskopijo (SEM) in optično mikroskopijo (OM). Ugotavljamo, da je plast analiziranih emajlov večfazna, saj je sestavljena iz amorfnih področji z različno kemično sestavo, kristalnih faz in por. Iz mikrokemične analize (SEM-EDS) prahov emajlov pa je razvidno, da določene kristalne faze v plasti emajla na jekleni pločevini izvirajo že iz samega postopka priprave prahov emajlov. Iz mikrokemične analize (SEM-EDS) fazne meje jeklo - emajl je razvidno, da potekajo med žganjem emajla na določenih mestih fazne meje tudi kemične reakcije, pri čemer kobalt difundira v jeklo. Izvedli smo tudi oceno vpliva toplotne prevodnosti emajlirane plasti na toplotno prehodnost emajlirane jeklene pločevine.

• Language: Slovenian
• Keywords: Toplotne lastnosti, metoda TPS, Hot Disk, Emajli, Emajlirana pločevina
• Work type: Bachelor thesis/paper
• Organization: NTF - Faculty of Natural Sciences and Engineering
• Year: 2018
• PID: 20.500.12556/RUL-100616
• COBISS.SI-ID: 1716831
• Publication date in RUL: 01.04.2018

FERČAK, Žan, 2018, Toplotne lastnosti emajlov in emajlirane pločevine [online]. Bachelor’s thesis. [Accessed 2 April 2025]. Retrieved from: https://repozitorij.uni-lj.si/IzpisGradiva.php?lang=eng&id=100616

Secondary language

• Language: English
• Title: Thermal properties of enamels and enamelled metal sheets

Abstract

In the course of the diploma work we performed measurements of the thermal properties of two enamel grades, used for kitchen appliances, by transient plane heat source method (Hot Disk TPS 2200) in accordance with the international standard ISO 22007. Since we could not perform direct measurements of the thermal properties of enameled steel sheets, samples of enamels were also prepared in the form of thick layers. The results obtained from the measurements of the thick layers are within the expected values of the enamels thermal properties. However, it has been established, that the density of the enamel layer has a significant effect on the thermal properties. The samples of the enameled steel sheet were metallographically prepared and analyzed by scanning electron microscopy (SEM-EDS) and optical microscopy (OM). We found out that the layer of analyzed enamels has multiphase structure, consisting of amorphous regions with different chemical composition, crystalline phases and pores. From the microchemical analysis results of the enamel powders it can be seen, that certain crystalline phases in the enameled layer originate from the process of preparing enamel powders. From the microchemical analysis (SEM-EDS) of the steel – enamel phase boundary, it is evident that chemical reactions occur during the firing of the enamel at certain points on the phase boundary, whereby the cobalt diffuses into the steel. An assessment of the influence of enamel layer thermal conductivity on the thermal transmittance of enameled steel sheet is also calculated.

• Keywords: Thermal properties, TPS method, Hot disk, enamels, enameled steel sheet