but.committee	prof. Ing. Jiří Švejcar, CSc. (předseda) prof. RNDr. Jaroslav Cihlář, CSc. (člen) Ing. Peter Tatarko, Ph.D. (člen) Ing. Lukáš Řehořek, Ph.D. (člen) prof. RNDr. Miroslav Liška, DrSc. (člen)	cs
but.defence	DDP přináší řadu původních a významných poznatků o přípravě a vlastnostech kompozitů na bázi skla, armovaného nanotrubičkami a nanoplátky nitridu bóru. Oba oponenti hodnotí kvalitu dosažených výsledků velmi vysoko, což ostatně dokládá i vysoký počet citací dosavadních publikací doktorandky.	cs
but.jazyk	angličtina (English)
but.program	Fyzikální a materiálové inženýrství	cs
but.result	práce byla úspěšně obhájena	cs
dc.contributor.advisor	Dlouhý, Ivo	en
dc.contributor.author	Saggar, Richa	en
dc.contributor.referee	Cihlář, Jaroslav	en
dc.contributor.referee	Tatarko, Peter	en
dc.date.accessioned	2019-06-14T11:05:36Z
dc.date.available	2019-06-14T11:05:36Z
dc.date.created	2016	cs
dc.description.abstract	Glasses and ceramics offer several unique characteristics over polymers or metals. However, they suffer from a shortcoming due to their brittle nature, falling short in terms of fracture toughness and mechanical strength. The aim of this work is to reinforce borosilicate glass matrix with reinforcements to increase the fracture toughness and strength of the glass. Boron nitride nanomaterials, i.e. nanotubes and nanosheets have been used as possible reinforcements for the borosilicate glass matrix. The tasks of the thesis are many fold which include: 1. Reinforcement of commercially derived and morphologically different (bamboo like and cylinder like) boron nitride nanotubes in borosilicate glass with the concentration of 0 wt%, 2.5 wt% and 5 wt% by ball milling process. Same process was repeated with reinforcing cleaned boron nitride nanotubes (after acid purification) into the borosilicate glass with similar concentrations. 2. Production of boron nitride nanosheets using liquid exfoliation technique to produce high quality and high aspect ratio nanosheets. These boron nitride nanosheets were reinforced in the borosilicate glass matrix with concentrations of 0 wt%, 2.5 wt% and 5 wt% by ball milling process. The samples were consolidated using spark plasma sintering. These composites were studied in details in terms of material analysis like thermo-gravimetric analysis, detailed scanning electron microscopy and transmission electron microscopy for the quality of reinforcements etc.; microstructure analysis which include the detailed study of the composite powder samples, the densities of bulk composite samples etc; mechanical properties which include fracture toughness, flexural strength, micro-hardness, Young’s modulus etc. and; tribological properties like scratch resistance and wear resistance. Cleaning process of boron nitride nanotubes lead to reduction in the Fe content (present in boron nitride nanotubes during their production as a catalyst) by ~54%. This leads to an improvement of ~30% of fracture toughness measured by chevron notch technique for 5 wt% boron nitride nanotubes reinforced borosilicate glass. It also contributed to the improvement of scratch resistance by ~26% for the 5 wt% boron nitride nanotubes reinforced borosilicate glass matrix. On the other hand, boron nitride nanosheets were successfully produced using liquid exfoliation technique with average length was ~0.5 µm and thickness of the nanosheets was between 4-30 layers. It accounted to an improvement of ~45% for both fracture toughness and flexural strength by reinforcing 5 wt% of boron nitride nanosheets. The wear rates reduced by ~3 times while the coefficient of friction was reduced by ~23% for 5 wt% boron nitride nanosheets reinforcements. Resulting improvements in fracture toughness and flexural strength in the composite materials were observed due to high interfacial bonding between the boron nitride nanomaterials and borosilicate glass matrix resulting in efficient load transfer. Several toughening and strengthening mechanisms like crack bridging, crack deflection and significant pull-out were observed in the matrix. It was also observed that the 2D reinforcement served as more promising candidate for reinforcements compared to 1D reinforcements. It was due to several geometrical advantages like high surface area, rougher surface morphology, and better hindrance in two dimensions rather than just one dimension in nanotubes.	en
dc.description.abstract	Glasses and ceramics offer several unique characteristics over polymers or metals. However, they suffer from a shortcoming due to their brittle nature, falling short in terms of fracture toughness and mechanical strength. The aim of this work is to reinforce borosilicate glass matrix with reinforcements to increase the fracture toughness and strength of the glass. Boron nitride nanomaterials, i.e. nanotubes and nanosheets have been used as possible reinforcements for the borosilicate glass matrix. The tasks of the thesis are many fold which include: 1. Reinforcement of commercially derived and morphologically different (bamboo like and cylinder like) boron nitride nanotubes in borosilicate glass with the concentration of 0 wt%, 2.5 wt% and 5 wt% by ball milling process. Same process was repeated with reinforcing cleaned boron nitride nanotubes (after acid purification) into the borosilicate glass with similar concentrations. 2. Production of boron nitride nanosheets using liquid exfoliation technique to produce high quality and high aspect ratio nanosheets. These boron nitride nanosheets were reinforced in the borosilicate glass matrix with concentrations of 0 wt%, 2.5 wt% and 5 wt% by ball milling process. The samples were consolidated using spark plasma sintering. These composites were studied in details in terms of material analysis like thermo-gravimetric analysis, detailed scanning electron microscopy and transmission electron microscopy for the quality of reinforcements etc.; microstructure analysis which include the detailed study of the composite powder samples, the densities of bulk composite samples etc; mechanical properties which include fracture toughness, flexural strength, micro-hardness, Young’s modulus etc. and; tribological properties like scratch resistance and wear resistance. Cleaning process of boron nitride nanotubes lead to reduction in the Fe content (present in boron nitride nanotubes during their production as a catalyst) by ~54%. This leads to an improvement of ~30% of fracture toughness measured by chevron notch technique for 5 wt% boron nitride nanotubes reinforced borosilicate glass. It also contributed to the improvement of scratch resistance by ~26% for the 5 wt% boron nitride nanotubes reinforced borosilicate glass matrix. On the other hand, boron nitride nanosheets were successfully produced using liquid exfoliation technique with average length was ~0.5 µm and thickness of the nanosheets was between 4-30 layers. It accounted to an improvement of ~45% for both fracture toughness and flexural strength by reinforcing 5 wt% of boron nitride nanosheets. The wear rates reduced by ~3 times while the coefficient of friction was reduced by ~23% for 5 wt% boron nitride nanosheets reinforcements. Resulting improvements in fracture toughness and flexural strength in the composite materials were observed due to high interfacial bonding between the boron nitride nanomaterials and borosilicate glass matrix resulting in efficient load transfer. Several toughening and strengthening mechanisms like crack bridging, crack deflection and significant pull-out were observed in the matrix. It was also observed that the 2D reinforcement served as more promising candidate for reinforcements compared to 1D reinforcements. It was due to several geometrical advantages like high surface area, rougher surface morphology, and better hindrance in two dimensions rather than just one dimension in nanotubes.	cs
dc.description.mark	P	cs
dc.identifier.citation	SAGGAR, R. Processing and Properties of 1D and 2D Boron Nitride Nanomaterials Reinforced Glass Composites [online]. Brno: Vysoké učení technické v Brně. Fakulta strojního inženýrství. 2016.	cs
dc.identifier.other	98141	cs
dc.identifier.uri	http://hdl.handle.net/11012/63681
dc.language.iso	en	cs
dc.publisher	Vysoké učení technické v Brně. Fakulta strojního inženýrství	cs
dc.rights	Standardní licenční smlouva - přístup k plnému textu bez omezení	cs
dc.subject	Keywords: Boron nitride nanosheets	en
dc.subject	Boron nitride nanotubes	en
dc.subject	Borosilicate glass	en
dc.subject	Nanocomposite	en
dc.subject	Mechanical properties	en
dc.subject	Tribological properties.	en
dc.subject	Keywords: Boron nitride nanosheets	cs
dc.subject	Boron nitride nanotubes	cs
dc.subject	Borosilicate glass	cs
dc.subject	Nanocomposite	cs
dc.subject	Mechanical properties	cs
dc.subject	Tribological properties.	cs
dc.title	Processing and Properties of 1D and 2D Boron Nitride Nanomaterials Reinforced Glass Composites	en
dc.title.alternative	Processing and Properties of 1D and 2D Boron Nitride Nanomaterials Reinforced Glass Composites	cs
dc.type	Text	cs
dc.type.driver	doctoralThesis	en
dc.type.evskp	dizertační práce	cs
dcterms.dateAccepted	2016-12-15	cs
dcterms.modified	2016-12-19-09:26:54	cs
eprints.affiliatedInstitution.faculty	Fakulta strojního inženýrství	cs
sync.item.dbid	98141	en
sync.item.dbtype	ZP	en
sync.item.insts	2021.11.12 13:23:47	en
sync.item.modts	2021.11.12 12:34:11	en
thesis.discipline	Fyzikální a materiálové inženýrství	cs
thesis.grantor	Vysoké učení technické v Brně. Fakulta strojního inženýrství. Ústav materiálových věd a inženýrství	cs
thesis.level	Doktorský	cs
thesis.name	Ph.D.	cs

Processing and Properties of 1D and 2D Boron Nitride Nanomaterials Reinforced Glass Composites

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