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https://ptsldigital.ukm.my/jspui/handle/123456789/499657Full metadata record
| DC Field | Value | Language |
|---|---|---|
| dc.contributor.advisor | Roslan Abd Shukor, Prof. Dato Dr. | - |
| dc.contributor.author | Nur Helmi @ Nur Jannah Azman (P58214) | - |
| dc.date.accessioned | 2023-10-13T09:33:31Z | - |
| dc.date.available | 2023-10-13T09:33:31Z | - |
| dc.date.issued | 2014-09-10 | - |
| dc.identifier.other | ukmvital:80693 | - |
| dc.identifier.uri | https://ptsldigital.ukm.my/jspui/handle/123456789/499657 | - |
| dc.description | Kesan penambahan nanozarah Co3O4 dengan saiz berlainan terhadap sifat superkonduktor Bi1.6Pb0.4Sr2Ca2Cu3O10 dalam bentuk pukal dan pita telah dikaji. Teknik sepemendakan digunakan untuk menyediakan serbuk superkonduktor Bi1.6Pb0.4Sr2Ca2Cu3O10 (Bi-2223). Tiga saiz purata Co3O4 (10±2, 30±4 dan 50±4 nm) dengan komposisi 0.00 hingga 0.05% berat telah ditambah ke dalam serbuk pukal. Kesan penambahan nanozarah Co3O4 ke atas pembentukan fasa, mikrostruktur dan morfologi sampel, suhu genting dan ketumpatan arus genting (Jc) tanpa medan magnet dan di dalam medan magnet telah dikaji. Hasil kiraan pecahan isipadu fasa, menunjukkan sampel dengan amaun penambahan x=0.01% berat (10 nm), x=0.02% berat (30 nm), dan x=0.01% berat (50 nm) nanozarah Co3O4 menunjukkan peratus fasa Bi-2223 yang tertinggi iaitu 72, 74 and 72 %, masing-masing. Pecahan isipadu fasa Bi-2223 mulai menurun apabila kuantiti nano Co3O4 semakin meningkat. Suhu genting sifar (Tc-sifar) dan suhu genting mula (Tc-mula) bagi sampel tulen adalah 100 K dan 110 K masing-masing. Bagi sampel yang ditambah Co3O4 (10 nm), sampel x=0.01% berat menunjukkan Tc-sifar tertinggi (102 K) dan menurun dengan penambahan seterusnya. Walau bagaimanapun suhu genting sifar (Tc(R=0)) didapati menurun dengan penambahan Co3O4 (30 nm) pada 0.01 hingga 0.05% berat dan berada di antara 91 K hingga 98 K selari dengan penurunan pecahan isipadu fasa Bi-2223. Suhu genting sifar (Tc-sifar) bagi semua sampel dengan penambahan Co3O4 (50 nm) juga berkurangan dengan pertambahan berat Co3O4. Ketumpatan arus genting pada 30 dan 77 K bagi sampel dengan penambahan nanozarah adalah lebih tinggi daripada sampel tanpa Co3O4. Pita disediakan melalui kaedah serbuk dalam tiub (PIT). Pita Bi1.6Pb0.4Sr2Ca2Cu3O10 telah disediakan berdasarkan keputusan Jc tertinggi sampel pukal. Tiga saiz purata nanozarah Co3O4 telah ditambah masing-masing dengan komposisi x=0.03, 0.02 dan 0.01% berat. Kebanyakan sampel pita dengan penambahan nanozarah Co3O4 memberi nilai Jc yang lebih tinggi daripada sampel pita tanpa Co3O4. Ini menunjukkan nanozarah Co3O4 membantu dalam peningkatan ketumpatan arus genting. Walau bagaimanapun peningkatan tempoh pensinteran dari 50 jam ke 150 jam tidak memberi kesan pada pita dengan Co3O4 (10 dan 30 nm). Jc tertinggi diperolehi dalam pita dengan Co3O4 (50 nm dan 150 jam) dengan Jc = 8780 A/cm2 pada 30 K dan 5030 A/cm2 pada 77 K. Arus genting, Jc melawan medan magnet, B bagi semua sampel pita (10, 30, 50 nm) yang disinter selama 50, 100 dan 150 jam didapati bertambah berbanding dengan sampel pita tanpa Co3O4. Kesemua sampel pita menunjukkan fasa Bi-2223 sebagai fasa dominan dengan sedikit kehadiran fasa Bi-2212 sebagai fasa sekunder. Pensinteran 150 jam tidak meningkatkan kualiti sampel tetapi menunjukkan sedikit penurunan pecahan isipadu fasa Bi-2223. Kajian ini menunjukkan bahawa zarah Co3O4 bersaiz nanometer telah memperbaiki sifat angkutan arus pita Bi-2223 dan bertindak sebagai pusat pengepin fluks yang berkesan. Kesan pusat pengepinan adalah yang terbaik dan berkesan apabila saiz nanozarah mendekati panjang koheren, ξ. Sifat-sifat superkonduktor Bi-2223 menjadi bertambah baik setelah nanozarah Co3O4 ditambah dan ini dikaitkan dengan peningkatan dalam ikatan antara butiran dan pusat-pusat pengepinan fluks yang menyebabkan Jc meningkat dalam sampel pukal dan pita.,The effects of different nanosized Co3O4 addition on the superconducting properties of Bi1.6Pb0.4Sr2Ca2Cu3O10 (Bi-2223) superconductor in bulk and tape form were investigated. The co-precipitation technique was used in the preparation of Bi1.6Pb0.4Sr2Ca2Cu3O10 (Bi-2223) superconductor powder. Three average sizes of Co3O4 (10±2, 30±4 dan 50±4) with nominal composition ranging from 0.00 to 0.05 wt. % were added. The effects of nano Co3O4 addition on the phase formation, microstructure and morphology, critical temperature and transport critical current density (Jc) in zero and applied magnetic field, were also studied. Samples with x=0.01 wt. % (10 nm), x=0.02 wt. % (30 nm) and x=0.01 wt. % (50 nm) of nanosized Co3O4 showed the highest percentage of Bi-2223 phase with 72, 74 and 72 % respectively. However, the volume fraction of Bi-2223 phase decreased with further increase in nano Co3O4. The zero-resistance temperature (Tc(R=0)) and onset transition temperature (Tc-onset) for non-added sample is 100 K and 110 K, respectively. For samples with Co3O4 addition (10 nm), the x=0.01 wt. % showed the highest critical temperature (102 K) and it decreased with further addition. However, Tc(R=0) decreased with the addition of Co3O4 (30 nm) of 0.01 to 0.05 wt% and is between 91 K and 98 K in parallel with the decrease in the volume fraction of Bi-2223 phase. Tc-zero for all samples with the addition of Co3O4 (50 nm) also decreased with increasing weight of Co3O4. The critical current density at 30 and 77 K for all samples with the addition of nano-particles was higher than the non-added sample. The tapes were prepared by the powder in tube (PIT) method. Bi1.6Pb0.4Sr2Ca2Cu3O10 tapes were prepared based on the results of the highest Jc of the bulk samples. Three average sizes of nanosized Co3O4 were added with x = 0.03, 0.02 and 0.01 wt. %. All of the added tapes have higher Jc than the non-added tape. This result showed that nano Co3O4 particles help in the improvement of the critical current density. However, increasing the sintering time from 50 to 150 h did not affect the tape with Co3O4 (10 and 30 nm). The highest Jc was obtained in tape with Co3O4 50 nm sintered for 150 h with Jc=8800 A/cm2 at 30 K and 5030 A/cm2 at 77 K. The critical current density, Jc versus magnetic field B for all tape samples (10, 30, 50 nm) sintered for 50, 100 and 150 h increased compared with the non-added tape. All tape showed Bi-2223 phase as the dominant phase and Bi-2212 as the secondary phase. The extension of the sintering time to 150 h does not improve the quality of sample, but showed a slight decrease in the volume fraction of Bi-2223 phase. This study showed that nanosized Co3O4 particles improved the transport current properties of Bi-2223 tape and act as effective flux pinning center. The effect of pinning center is at its best when their sizes are closer to the coherence length, ξ. The overall superconducting properties of Bi-2223 have been improved after the addition of Co3O4 nanoparticles attributed to an increase in the intergrain connectivity and flux pinning centers which result in enhanced Jc in Co3O4 added bulk and tape samples.,Ph.D. | - |
| dc.language.iso | may | - |
| dc.publisher | UKM, Bangi | - |
| dc.relation | Faculty of Science and Technology / Fakulti Sains dan Teknologi | - |
| dc.rights | UKM | - |
| dc.subject | Superkonduktor | - |
| dc.subject | Nanozarah | - |
| dc.subject | Flux pinning | - |
| dc.subject | Dissertations, Academic -- Malaysia | - |
| dc.subject | Universiti Kebangsaan Malaysia -- Dissertations | - |
| dc.title | Ketumpatan arus genting angkutan superkonduktor (Bi1.6pb0.4)Sr2Ca2Cu3o10 pukal dan pita dengan penambahan nanozarah co3o4 berlainan saiz sebagai pusat pengepinan fluks | - |
| dc.type | Theses | - |
| dc.format.pages | 175 | - |
| dc.identifier.callno | QC611.96.N846 2014 tesis | - |
| dc.identifier.barcode | 001344 | - |
| Appears in Collections: | Faculty of Science and Technology / Fakulti Sains dan Teknologi | |
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| File | Description | Size | Format | |
|---|---|---|---|---|
| ukmvital_80693+SOURCE1+SOURCE1.0.PDF Restricted Access | 11.18 MB | Adobe PDF |  View/Open |
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