Abstract
The initial objective of the present PhD Thesis has been the study of the viability of inkjet printing systems for the manufacturing of layered and patterned ceramic functional coatings. For this purpose, two model systems were studied: the copper, barium and yttrium mixed oxide (YBa2Cu3O7-x), with application in the production of superconducting tapes, and the lanthanum, strontium and manganese mixed oxide (La0.7Sr0.3MnO3), having properties of colossal magnetoresistance and metal-insulator transition.The present Thesis is divided in seven chapters, being the first an introduction to functional ceramic oxides and their manufacturing by means of Chemical Solution Deposition (CSD) methodology and the inkjet deposition systems currently used, pointing out the added value which offers the implementation of the inkjet printing technology with the CSD methodology.
In chapter 2, the ¿state of the art¿ of inkjet printing is reviewed, together with the different existing printing technologies and ink requirements. All the ink development and characterization, and the thermal treatments performed for the various ceramic oxide systems object of this work are presented in Chapter 3, with special emphasis to the morphological, structural and magnetic characterization techniques.
Chapter 4 begins with an historical overview of drop formation process and the influence of the relevant ink physicochemical properties and the actuation parameters of the printhead on this process. Particularly, the dependence of drop characteristics such as drop speed and drop volume with the ink rheological characteristics and the driving waveform parameters of the printhead were analyzed in order to obtain a reliable drop ejection process.
In chapters 5 and 6, the application of inkjet printing technology to the previous cited ceramic oxide systems is presented. In Chapter 5, the superconducting ceramic material YBa2Cu3O7-x was obtained in continuous layers and also in form of tracks and drawings. It has been shown that by modifying drop volume and the number of drops per unit area, film thickness may be tuned.
Chapter 6 exhibits the formation of the magnetoresistive material (La0.7Sr0.3MnO3) also in continuous coatings and patterns. As an example, it has been demonstrated the manufacturing of a magnetoresistive device with high reproducibility by means of a predetermined design.
Finally, in chapter 7, preliminary results in the upscaling of ceramic coated tapes are presented. These results represent the starting point for further technological development to longer lengths, demonstrating the enormous feasibility to implement the CSD methodology with the inkjet printing technology to produce long lengths functional ceramic oxides on metallic tapes in continuous reel to reel systems.
At last, general conclusions are presented and an appendix is also included with a glossary of the different concepts of fluid dynamics mentioned throughout the text.
During this PhD Thesis, it has been demonstrated for the first time, the possibility of using the inkjet printing technology as a deposition technique for the manufacturing of functional ceramic oxides. Moreover, the coatings obtained exhibit properties which are comparable with the more conventional deposition techniques such as spin coating, with the added value which offers the inkjet printing technology to produce patterned coatings in a single pass of different thickness and shapes.
| Date of Award | 8 May 2014 |
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| Original language | English |
| Supervisor | Javier Alberto Jose Granados Garcia (Director), Susagna Ricart (Director) & Ramon Yáñez Lopez (Tutor) |