Mohamed Ansari, Suriyati (2014) Formation Of Zirconia Sheets with Nanotubular Structure Prepared by Anodization of Zirconium. Masters thesis, Universiti Sains Malaysia.
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Abstract
Dalam karya ini, proses anodik dilakukan untuk menghasilkan lapisan anodik yang terdiri daripada tiub nano ZrO2. Lapisan anodik kemudian dikeluarkan dari kepingan Zr untuk menghasilkan berdiri bebas lembaran ZrO2 tiub nano. Jenis-jenis karbonat, berbeza kepekatan karbonat, voltan penganodan dan juga masa penganodan telah dieksperimen bertujuan untuk membentuk lembaran ZNTs. Kehadiran karbonat, Na2CO3 dan K2CO3 sebagai penambah memainkan peranan yang penting dalam pembentukan kepingan tiub nano. Untuk membandingkan, dalam EG ditambah dengan 3 ml 1 M K2CO3 menunjukkan lebih pembentukan kepingan tiub nano berbanding EG dengan Na2CO3. Dalam pembentukan ZNTs, H+ dilepaskan dalam tiub nano dan apabila H+ bertindak balas dengan CO32-, gas CO2 dilepaskan. Pembentukan gas CO2 memberi kesan kepada lekatan filem ZrO2 dari foil. Kesan kepekatan K2CO3 yang berbeza menambah, jumlah kepingan tiub nano yang terbentuk. Bagi kesan voltan penganodan dan masa, didapati bahawa pada 40 V dan 60 V, jumlah ZNTs dibentuk dan pada 60 V, filem itu adalah lebih mudah untuk dikeluarkan daripada foil Zr. Bagi kesan masa penganodan, ia seolah-olah bahawa pada masa yang lebih lama, tindak balas lebih bagi CO32- dan H+ berlaku membentuk lebih CO2. Gas CO2 yang dihasilkan daripada tindak balas CO32- dan H+ terkumpul pada antara muka logam dan oksida dan membuat filem oksida anodik untuk menanggalkan dengan mudah dari Zr substrat tanpa memerlukan prarawatan. Lembaran tiub nano ZrO2 didapati amorfus, oleh itu ia telah disepuh lindap pada tiga suhu yang berbeza 200 ⁰C, 400 ⁰C dan 600 ⁰C. Pembentukan fasa dan perubahan pada setiap suhu diperhatikan dengan semua tetragon (T), padu (C), dan wujud bersama-monoklinik (M) fasa selepas penyepuhlindapan pada 400 ⁰C dan 600 ⁰C Aktiviti lembaran tiub nano ZrO2 anil adalah kajian oleh degradasi MO. Selepas 300 minit, kira-kira 37% daripada MO telah di hina oleh sampel disepuh lindap pada 600 ⁰C, 35% daripada MO dihina oleh sampel anil pada 400 ⁰C dan 22% daripada MO dihina oleh sampel disepuh lindap pada 200 ⁰C. Ini menunjukkan bahawa penghabluran adalah penting dalam fotopemangkinan. ________________________________________________________________________________________________________________________ In this work, anodic process was done to produce anodic layer of comprising of ZrO2 nanotubes. The anodic layer was then removed from the Zr foil to produce free standing ZrO2 nanotube sheets. Types of carbonates, different concentration of carbonates, anodization voltage and also anodization time were experimented aiming at forming ZNTs sheets. The presence of carbonates, K2CO3 and Na2CO3 as an additive plays an important role during the formation of the nanotube sheets. To compare, in EG added with 3 ml 1 M K2CO3 shows more nanotube sheets formation compared to EG with Na2CO3. In ZNTs formation, H+ is released in the nanotubes and when H+ reacts with CO32-, CO2 gas is released. The formation of CO2 gas effect the adhesion of ZrO2 film from the foil. Effect of different concentrations of K2CO3 added, the amount of nanotube sheets that formed was also increased. As for the effect of anodization voltage and time, it appears that at 40 V and 60 V, the amount of ZNTs were formed and at 60 V, the film was easier to be removed from Zr foil. As for the effect of anodization time, it seems that at longer time, more reaction between the CO32- and H+ occurs forming more CO2. The CO2 gas produced from the reaction of CO32- and H+ accumulated at the metal and oxide interface and makes the anodic oxide film to detach easily from Zr substrate without the need of pretreatment. The ZrO2 nanotube sheets were found to be amorphous, thus it were annealed at three different temperatures of 200 ⁰C, 400 ⁰C and 600 ⁰C. The phase formation and transformation at each temperature was observed with all tetragonal (T), cubic (C), and monoclinic (M) phase co-exist after annealing at 400 ⁰C and 600 ⁰C. The activity of the annealed ZrO2 nanotube sheets was study by degradation of MO. After 300 min, about 37 % of the MO was degraded by the annealed sample at 600 ⁰C, 35 % of MO degraded by sample annealed at 400 ⁰C and 22 % of MO degraded by sample annealed at 200 ⁰C. This indicates that crystallinity is important in photocatalysis
| Item Type: | Thesis (Masters) |
|---|---|
| Additional Information: | full text available at http://irplus.eng.usm.my:8080/ir_plus/institutionalPublicationPublicView.action?institutionalItemId=1922 |
| Subjects: | T Technology T Technology > TP Chemical Technology > TP1-1185 Chemical technology |
| Divisions: | Kampus Kejuruteraan (Engineering Campus) > Pusat Pengajian Kejuruteraan Bahan & Sumber Mineral (School of Material & Mineral Resource Engineering) > Thesis |
| Depositing User: | Mr Mohd Jasnizam Mohd Salleh |
| Date Deposited: | 05 Jun 2018 03:59 |
| Last Modified: | 05 Jun 2018 09:51 |
| URI: | http://eprints.usm.my/id/eprint/40693 |
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