Ispitivanje elastičnih svojstava tinjaca

undergraduate thesis

• Title (english): Examination of elastic properties of micas
• Author: Marko Bermanec
• Mentor: Marijana Đaković (mentor)
• Mentor: Nenad Tomašić (komentor)
• Committee member: Nenad Tomašić (predsjednik povjerenstva)
• Committee member: Marijana Đaković (član povjerenstva)
• Committee member: Jasenka Sremac (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Geology); Zagreb
• Defense date and country: 2021-09-28, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Geology

Abstract

Elastičnost tri minerala iz grupe pravih tinjaca ispitivana je metodom čistog savijanja. Kako bi se eliminirao utjecaj dimenzije ispitivanih listića na rezultate, rezultati elastičnosti izraženi su u bezdimenzijskoj veličini stupnja savitljivosti (ε). Najveći utjecaj na mehanička svojstva pravih tinjaca ima međuslojni kation, koji je u svim ispitivanim uzorcima bio K+ pa su ostale kristalokemijske razlike između muskovita, biotita i lepidolita rezultirale i različitom elastičnosti. Muskovit se kao dioktaedrijski tinjac pokazao najmanje elastičnim što se može objasniti većim naprezanjima tetraedrijskog sloja zbog prisutnih vakancija u oktaedrijskom sloju. Kod lepidolita i biotita glavni parametar zbog kojeg je lepidolit elastičniji mogao bi biti anionski sastav. U lepidolitu je prisutno znatno više fluora koji tvori jače vodikove veze u apikalnoj ravnini tetraedrijskih slojeva te tako bolje stabilizira kristalnu strukturu.

Abstract (english)

The elasticity of three minerals from the group of true mica was investigated by the method of pure bending. In order to eliminate the influence of the dimension of the examined mica crystals on the results, the elasticity results are expressed in the dimensionless form of the degree of flexibility (ε). The interlayer cation has the greatest influence on the mechanical properties of true mica. The dominant interlayer cation in all tested samples was K+, so other crystal-chemical differences between muscovite, biotite and lepidolite resulted in different elasticity. Muscovite as a dioctahedral mica proved to be the least elastic which can be explained by higher strain of the tetrahedral layer due to the present vacancies in the octahedral layer. In lepidolite and biotite, the main parameter that makes lepidolite more elastic could be the anionic composition. Significantly more fluorine is present in lepidolite, which forms stronger hydrogen bonds in the apical plane of the tetrahedral layers and thus better stabilizes the crystal structure.

• Keywords: elastičnost; pravi tinjci; čisto savijanje; kristalna struktura
• Keywords (english): elasticity; true mica; pure bending crystal structure
• Language: croatian
• URN:NBN: urn:nbn:hr:217:318169
• Study programme: Title: Geology; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) geologije (sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) geologije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2025-02-10 08:33:35