Prospects of the room temperature fabrication method for electroceramics:feasibility for printing techniques and integration with temperature-sensitive materials

Abstract The room temperature fabrication method for electroceramics allows manufacturing of relatively dense ceramic bodies with competent microwave dielectric properties. It is based on the use of water-soluble ceramic materials and pressure as the driving force for consolidation. Previously with this method, forming of the ceramic body has been done with uniaxial pressing in a mould. This work presents the applicability of 3D printing with extrusion and 2D printing through a stencil as alternative forming techniques for Li2MoO4-based all-ceramic samples. Successful printing was achieved through experimental optimization of the paste formulations. Compared to uniaxial pressing, the printed samples showed decreased relative densities due to the lower pressures available in the forming. As a result, the dielectric properties of the samples reached somewhat lower values, but still showed feasibility for microwave applications. In addition, the benefit of simultaneous processing and direct integration of Li2MoO4-based ceramics with temperature-sensitive materials offered by the low processing temperature was verified in this thesis. The results pave the way for fabrication of electronics and telecommunication devices with significant time, cost, and energy savings due to the applicability of room temperature fabricable Li2MoO4-based ceramics to different printing techniques and to integration with temperature-sensitive materials.Tiivistelmä Sähkökeraamien huoneenlämpötilan valmistusmenetelmällä on mahdollista valmistaa verrattain tiheitä keraamisia kappaleita, joilla on kilpailukykyiset dielektriset ominaisuudet mikroaaltoalueella. Menetelmä perustuu vesiliukoisten keraamisten materiaalien hyödyntämiseen ja paineen käyttöön tiivistymistä ajavana voimana. Aikaisemmin tällä menetelmällä keraaminen kappale on valmistettu puristamalla muotissa. Tässä työssä esitetään ekstruusioon perustuvan 3D-tulostuksen ja stensiilillä tehtävän 2D-painatuksen sovellettavuus vaihtoehtoisina valmistustekniikoina näille täysin keraamisille Li2MoO4-pohjaisille keraaminäytteille. Pastojen koostumusten optimoinnin ansiosta näytteiden valmistaminen onnistui toivotulla tavalla. Verrattuna puristamalla valmistettuihin näytteisiin, tulostetuilla ja painetuilla näytteillä oli pienempi suhteellinen tiheys johtuen näiden tekniikoiden käyttämistä alhaisemmista paineista. Siksi näytteiden dielektristen ominaisuuksien arvot olivat matalammat mutta ne olivat silti käyttökelpoisia mikroaaltoalueen sovelluksissa. Lisäksi tässä työssä osoitettiin, että Li2MoO4-pohjaisten keraamien samanaikainen prosessointi ja niiden yhdistäminen lämpöherkkien materiaalien kanssa on mahdollista. Tulokset viitoittavat tietä elektroniikan ja tietoliikennetekniikan komponenttien uusille aikaa, kustannuksia ja energiaa säästäville valmistusmenetelmille. Tämä johtuu huoneenlämpötilan valmistusmenetelmällä tehtävien Li2MoO4-pohjaisten keraamien soveltuvuudesta tulostus- ja painotekniikoihin ja niiden yhdistettävyydestä lämpötilaherkkien materiaalien kanssa

Li₂MoO₄-based composite ceramics fabricated from temperature- and atmosphere-sensitive MnZn ferrite at room temperature

Abstract The first magnetic ceramic composites manufactured, using the room-temperature densification method are reported. The samples were prepared at room temperature using Li₂MoO₄ as a matrix and MnZn ferrite with loading levels of 10–30 vol-% followed by postprocessing at 120°C. The method utilizes the water solubility of the dielectric Li₂MoO₄ and compression pressure instead of high temperatures typical of conventional solid-state sintering. Hence, composite manufacturing using temperature- and atmosphere-sensitive materials is possible without special conditions. This was demonstrated with MnZn ferrite, which is prone to oxidation when heat treated in air. Samples manufactured with room-temperature densification showed no signs of reactivity during processing, whereas reference samples sintered at 685°C suffered from oxidation and formation of an additional reaction phase. The densities achieved with different loading levels of MnZn ferrite with both methods were very similar. Measurements up to 1 GHz showed relatively high values of relative permittivity (21.7 at 1 GHz) and permeability (2.6 at 1 GHz) with 30 vol-% loading of MnZn ferrite in the samples manufactured by room-temperature densification. In addition, pre-granulation is proposed to improve the processability of the composite powders in room-temperature densification

Usage Data Analytics for Human-Machine Interactions with Flexible Manufacturing Systems: Opportunities and Challenges

Analyzing data from complex production systems and processes can be used in improving existing products, processes, and services, and innovating novel offerings. We report the findings from a six-month case study with a company developing flexible manufacturing systems. During a collaborative development process of a data analytics and visualization tool, our goal was to identify potential metrics, business opportunities, and challenges when utilizing logged data of end-users' human-machine interactions in development activities. Our key contributions include a characterization of the potential usage data metrics to be logged and visualized, identification of opportunities this data entails for business, and discussion about the challenges related to usage data logging in the studied context. Finally, we propose topics that should be considered in the organization before investing in usage data logging in the context of flexible manufacturing systems.acceptedVersionPeer reviewe

Becoming With : Towards the Inclusion of Animals as Participants in Design Processes

In this exploratory paper, we advocate for a way to mitigate the anthropocentrism inherent in interaction-design methodologies. We propose to involve animals that live in anthropic environments as participants in design processes. The current relationships between animals and technology have an inevitable impact on their well-being and raise fundamental ethical questions concerning our design policies. Drawing from the work of Bruno Latour and Donna Haraway, we argue for a situated approach in which we reflect upon concrete design contexts. We explore the notion of becoming with as a conceptual framework for the intuitive and bodily understanding that takes place between humans and animals when they encounter one-another in shared contexts. Adopting a research through design approach, we further explore this notion by reflecting upon two different participatory design projects with two dogs. We found these reflections to offer valuable perspectives for designers to analyse and discuss their iterative processes

Direct integration of dielectric all-ceramic thick films on a polymer substrate using room temperature fabrication

Abstract Direct integration of all-ceramic thick films and a polymer substrate has been realized for the first time without high temperature processing using the Room Temperature Fabrication method. Printable Li2MoO4-BaTiO3 composite pastes with 0, 10, and 20 vol.% of BaTiO3 were fabricated from the respective ceramic powders and water without organic additives or vehicles. The pastes were stencil printed on a polyimide substrate and dried at 120 °C without pressing or lamination. Using scanning electron microscopy, the films were observed to be in seamless contact with the substrate and to have a uniform microstructure. Relative permittivities of the ceramic films increased from 4.2 to 7.2 (at 2.5 GHz) and 4.5 to 7.5 (at 9.9 GHz) according to the vol.% content of the added BaTiO3, with corresponding dielectric losses from 10−3 to 10-2. The results show that the room temperature fabrication method enables 2D printing of all-ceramic thick films on temperature-sensitive substrates

3D printed dielectric ceramic without a sintering stage

Abstract This paper presents for the first time the fabrication of dielectric ceramic parts by 3D printing without sintering. The printable paste was prepared by mixing a carefully selected amount of water-soluble Li₂MoO₄ powder with water. A viscous mixture of solid ceramic particles and saturated aqueous phase was formed with a solid content of 60.0 vol.%. Printing of the sample discs was conducted with material extrusion using a low-cost syringe-style 3D printer. The consolidation and densification of the printed parts occurred during both printing and drying of the paste due to extrusion pressure, capillary forces, and recrystallization of the dissolved Li₂MoO₄. Complete drying of the paste was ensured by heating at 120 °C. The microstructure showed no delamination of the printed layers. Relatively high densities and good dielectric properties were obtained, especially when considering that no sintering and only pressure from the extrusion was employed. This approach is expected to be feasible for similar ceramics and ceramic composites

Solid air-low temperature manufacturing of ultra-low permittivity composite materials for future telecommunication systems

Abstract The frequency spectrum to be used by future wireless telecommunication systems such as 5G and beyond requires novel materials which are environment-friendly, are low cost and, most importantly, have low dielectric loss and permittivity when approaching higher frequencies. In this work, the development of all-inorganic composites with a relative permittivity of ~1.2 and loss tangents in the range of 10−3 is presented. The composites were fabricated at the exceptionally low temperature of 120°C and were based on lithium molybdate (Li2MoO4) ceramic as a water-soluble binder reinforced by quartz fibers. The relative permittivity was further decreased by the addition of hollow micron-sized glass spheres having very low dielectric loss. A simple manufacturing method through filtration, stencil printing and drying is presented. The microstructure of the composites was investigated with FESEM microscopy and the dielectric properties by SPDR. Printing tests were carried out in order to evaluate the possibility of using the proposed composites in, for example, printed antenna applications

Characterization of Li₂MoO₄/BaTiO₃ all-ceramic films on organic substrate printed capacitors at 45 MHz–10 GHz

Abstract This article presents novel all-ceramic composite films used as a screen-printed capacitors on polymer surface and their characterization at 45-MHz to 10-GHz frequency range. All-ceramic composite paste is based on lithium molybdate (Li₂MoO₄), barium titanate (BaTiO₃), and water manufactured by the room temperature fabrication (RTF) method. For the determination of the permittivity and the loss tangent of the materials, ceramic thick films are printed on the top of an interdigital-shaped microwave capacitors using pastes with 0, 10, and 20 vol.% of BaTiO₃ filler in Li₂MoO₄ followed by a drying process at 120 °C. The electrical properties of the capacitors, capacitance, and quality value are derived from measured S-parameter results, whereas the electrical properties of the ceramic thick-film materials, real, and imaginary values of permittivity are derived from the measured results through computer simulations. The electrical properties of the ceramic material, such as moderate permittivity and moderately low-loss tangent, could be adjusted by changing the volume fraction of the BaTiO₃ filler to match the demands of different areas of applications. The obtained results are verified with five samples of each ceramic composition. The results show the capacitance values of 0.30 pF for an uncoated capacitor and 0.55, 0.67, and 0.95 pF with coatings of Li₂MoO₄ with 0, 10, and 20 vol.% of BaTiO₃ composites, respectively, at 2.5-GHz frequency. The calculated relative permittivity (εr) values for the same materials are 3.70, 5.23, and 6.43, and loss tangent values are 0.035, 0.027, and 0.036 at 2.5 GHz. These novel all-ceramic capacitor composite materials are applicable for the RF components used in telecommunication applications in the frequency range of 45 MHz–10 GHz, thus widening the technology roadmap in terms of material choices for different applications, especially high thermal resistant materials

The 'Hedonic' in Human-Computer Interaction – History, Contributions, and Future Research Directions

Over the recent years, the notion of a non-instrumental, hedonic quality of interactive products received growing interest. Based on a review of 151 publications, we summarize more than ten years research on the hedonic to provide an overview of definitions, assessment tools, antecedents, consequences, and correlates. We highlight a number of contributions, such as introducing experiential value to the practice of technology design and a better prediction of overall quality judgments and product acceptance. In addition, we suggest a number of areas for future research, such as providing richer, more nuanced models and tools for quantitative and qualitative analysis, more research on the consequences of using hedonic products and a better understanding of when the hedonic plays a role and when not