Improvement in Magnetic Properties of Samarium-Cobalt (1:5) Alloy through Controlled Material Processing / (Record no. 610650)
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| 000 -LEADER | |
|---|---|
| fixed length control field | 03537nam a22001577a 4500 |
| 082 ## - DEWEY DECIMAL CLASSIFICATION NUMBER | |
| Classification number | 670 |
| 100 ## - MAIN ENTRY--PERSONAL NAME | |
| Personal name | Akhtar, Saleem |
| 245 ## - TITLE STATEMENT | |
| Title | Improvement in Magnetic Properties of Samarium-Cobalt (1:5) Alloy through Controlled Material Processing / |
| Statement of responsibility, etc. | Saleem Akhtar |
| 264 ## - PRODUCTION, PUBLICATION, DISTRIBUTION, MANUFACTURE, AND COPYRIGHT NOTICE | |
| Place of production, publication, distribution, manufacture | Islamabad : |
| Name of producer, publisher, distributor, manufacturer | SMME- NUST; |
| Date of production, publication, distribution, manufacture, or copyright notice | 2021. |
| 300 ## - PHYSICAL DESCRIPTION | |
| Extent | 195p. |
| Other physical details | Soft Copy |
| Dimensions | 30cm. |
| 500 ## - GENERAL NOTE | |
| General note | Permanent magnets are defined as solid materials that provide sufficiently high<br/>magnetic flux and offer resistance to demagnetizing fields. High magnetic flux can be<br/>controlled by changing the chemical composition of the permanent magnetic material but<br/>the demagnetizing field resistance called coercivity depends upon the shape or crystal<br/>anisotropies and the process in which microscopic regions of the material are further subdivided.<br/>Permanent magnetic materials include a variety of ceramics, intermetallics and<br/>alloys. Samarium-cobalt (SmCo) magnets are rare earth magnets and are known for their<br/>high coercivity and Curie temperature. In this class of magnets, SmCo5 has a potential to<br/>demonstrate highest coercivity due to its high magneto-crystalline anisotropy. However;<br/>only 4% of the theoretical coercivity values are achieved so far. One method of improving<br/>the coercivity is through alloying while the other is through process control. The latter<br/>technique is used to improve the microstructure of the magnet.<br/>In this research the improvement of coercivity of SmCo5 is focused through<br/>process control. The microstructure of SmCo5 has been controlled through processing at<br/>the stages of manufacturing i.e., casting and ball milling. In the first stage, the<br/>microstructure was controlled using conformal cooling channels in the mold i.e., through<br/>controlled solidification. The samples from this process were compared with the spin<br/>casting technique. It was observed that the formation of Sm2Co7 and Sm5CO19 are<br/>responsible for lowering the coercivity of the magnetic material. Therefore, the<br/>solidification temperature was controlled to achieve better microstructure. The results<br/>show that the casting produced at the lower temperatures had nano-sized peritectic<br/>lamellar structure. These nano structures are belived to improve the coercivity of SmCo5<br/>to 32.9 kOe, which is one of the highest reported value.<br/>In the second part of this thesis, the focus was on the optimization of the ball<br/>milling parameters i.e., the process by which fine powder is produced. Ball-milling affects<br/>the shape, size distribution and mean particle size and consequently the final magnetic<br/>properties. The Taguchi L9 experimentation was designed to determine the effect of<br/>different parameters on the magnetic properties of the final product. It was noted that the<br/>ball milling speed, ball to powder ratio and time are the most significant process<br/>parameters which affects the coercivity of the final magnet. Best combination of these<br/>parameters was time and ball to powder ratio.<br/>ix<br/>In this work novel mold design was introduced which can provide the casting with<br/>fine microstructure. The coercivity values upto 32.9 kOe were achieved with the same<br/>mold design. Further, the optimization of ball milling parameters through Taguchi was<br/>done for SmCo5. Novel nano-structures were observed in SmCo5 before and after sintering<br/>process. |
| 650 ## - SUBJECT ADDED ENTRY--TOPICAL TERM | |
| Topical term or geographic name entry element | PhD in Design and Manufacturing Engineering |
| 700 ## - ADDED ENTRY--PERSONAL NAME | |
| Personal name | Supervisor : Dr. Mushtaq Khan |
| 856 ## - ELECTRONIC LOCATION AND ACCESS | |
| Uniform Resource Identifier | <a href="http://10.250.8.41:8080/xmlui/handle/123456789/28208">http://10.250.8.41:8080/xmlui/handle/123456789/28208</a> |
| 942 ## - ADDED ENTRY ELEMENTS (KOHA) | |
| Source of classification or shelving scheme | |
| Koha item type | Thesis |
| Withdrawn status | Permanent Location | Current Location | Shelving location | Date acquired | Full call number | Barcode | Koha item type |
|---|---|---|---|---|---|---|---|
| School of Mechanical & Manufacturing Engineering (SMME) | School of Mechanical & Manufacturing Engineering (SMME) | E-Books | 07/30/2024 | 670 | SMME-Phd-13 | Thesis |