Woo Y. Lee

Bio: Woo Y. Lee is an academic researcher from Stevens Institute of Technology. The author has contributed to research in topics: Coating & Chemical vapor deposition. The author has an hindex of 29, co-authored 135 publications receiving 3621 citations. Previous affiliations of Woo Y. Lee include Max Planck Society & Reaction Design.

Substrate and bond coat compositions: factors affecting alumina scale adhesion

Abstract: Thermally grown oxide scales that form beneath ZrO 2 top coats play an important role in determining the performance of thermal barrier coatings. Numerous factors, including the composition of both the alloy substrate and the bond coat, affect adhesion of the α -Al 2 O 3 scale. Three areas of focus in the formation of an `ideal', adherent scale encompass: (1) migration of Al and other elements in the metal substrate, (2) segregation of elements to the metal–scale interface and the scale grain boundaries, and (3) generation of stresses in the scale. Examples of the effects of reactive elements, Pt, indigenous S, and reaction temperature on scale adhesion are discussed.

Temperature-Dependent Electrical Properties of Graphene Inkjet-Printed on Flexible Materials

Abstract: Graphene electrode was fabricated by inkjet printing, as a new means of directly writing and micropatterning the electrode onto flexible polymeric materials. Graphene oxide sheets were dispersed in water and subsequently reduced using an infrared heat lamp at a temperature of ~200 °C in 10 min. Spacing between adjacent ink droplets and the number of printing layers were used to tailor the electrode's electrical sheet resistance as low as 0.3 MΩ/□ and optical transparency as high as 86%. The graphene electrode was found to be stable under mechanical flexing and behave as a negative temperature coefficient (NTC) material, exhibiting rapid electrical resistance decrease with temperature increase. Temperature sensitivity of the graphene electrode was similar to that of conventional NTC materials, but with faster response time by an order of magnitude. This finding suggests the potential use of the inkjet-printed graphene electrode as a writable, very thin, mechanically flexible, and transparent temperature sensor.

Concept of Functionally Graded Materials for Advanced Thermal Barrier Coating Applications

Abstract: This feature article explores the concept of creating functionally graded metal-ceramic composite microstructures for thermal barrier coatings used in gas-turbine applications. From a thermomechanical perspective, this concept offers the possibility of significantly improving the life and reliability of thermal barrier coatings. However, prior research reveals that progress has been somewhat limited because of the oxidative instability exhibited by some metal-ceramic composite microstructures. The present study addresses some of the materials criteria and research issues associated with preparing chemically stable, yet mechanically durable, graded metal-ceramic microstructures for realistic application environments.

Towards an in vivo biologically inspired nanofactory

Abstract: Nanotechnology is having a major impact on medicine and the treatment of disease, notably in imaging and targeted drug delivery. It may, however, be possible to go even further and design 'pseudo-cell' nanofactories that work with molecules already in the body to fight disease.

The Superalloys: Fundamentals and Applications

Abstract: 1. Introduction 2. The physical metallurgy of nickel and its alloys 3. Single crystal superalloys for blade applications 4. Superalloys for turbine disc applications 5. Environmental degradation: the role of coatings 6. Summary and future trends.

Silicon Nitride and Related Materials

Abstract: Silicon nitride has been researched intensively, largely in response to the challenge to develop internal combustion engines with hot-zone components made entirely from ceramics. The ceramic engine programs have had only partial success, but this research effort has succeeded in generating a degree of understanding of silicon nitride and of its processing and properties, which in many respects is more advanced than of more widely used technical ceramics. This review examines from the historical standpoint the development of silicon nitride and of its processing into a range of high-grade ceramic materials. The development of understanding of microstructure–property relationships in the silicon nitride materials is also surveyed. Because silicon nitride has close relationships with the SiAlON group of materials, it is impossible to discuss the one without some reference to the other, and a brief mention of the development of the SiAlONs is included for completeness.

Towards flexible solid-state supercapacitors for smart and wearable electronics

Abstract: Flexible solid-state supercapacitors (FSSCs) are frontrunners in energy storage device technology and have attracted extensive attention owing to recent significant breakthroughs in modern wearable electronics In this study, we review the state-of-the-art advancements in FSSCs to provide new insights on mechanisms, emerging electrode materials, flexible gel electrolytes and novel cell designs The review begins with a brief introduction on the fundamental understanding of charge storage mechanisms based on the structural properties of electrode materials The next sections briefly summarise the latest progress in flexible electrodes (ie, freestanding and substrate-supported, including textile, paper, metal foil/wire and polymer-based substrates) and flexible gel electrolytes (ie, aqueous, organic, ionic liquids and redox-active gels) Subsequently, a comprehensive summary of FSSC cell designs introduces some emerging electrode materials, including MXenes, metal nitrides, metal–organic frameworks (MOFs), polyoxometalates (POMs) and black phosphorus Some potential practical applications, such as the development of piezoelectric, photo-, shape-memory, self-healing, electrochromic and integrated sensor-supercapacitors are also discussed The final section highlights current challenges and future perspectives on research in this thriving field

An overview of the applications of graphene-based materials in supercapacitors.

Abstract: Due to their unique 2D structure and outstanding intrinsic physical properties, such as extraordinarily high electrical conductivity and large surface area, graphene-based materials exhibit great potential for application in supercapacitors. In this review, the progress made so far for their applications in supercapacitors is reviewed, including electrochemical double-layer capacitors, pseudo-capacitors, and asymmetric supercapacitors. Compared with traditional electrode materials, graphene-based materials show some novel characteristics and mechanisms in the process of energy storage and release. Several key issues for improving the structure of graphene-based materials and for achieving better capacitor performance, along with the current outlook for the field, are also discussed.

Capacitive energy storage in micro-scale devices: recent advances in design and fabrication of micro-supercapacitors

Abstract: Miniaturized energy storage is essential for the continuous development and further miniaturization of electronic devices. Electrochemical capacitors (ECs), also called supercapacitors, are energy storage devices with a high power density, fast charge and discharge rates, and long service life. Small-scale supercapacitors, or micro-supercapacitors, can be integrated with microelectronic devices to work as stand-alone power sources or as efficient energy storage units complementing batteries and energy harvesters, leading to wider use of these devices in many industries. In recent years, the research in this field has rapidly advanced and micro-supercapacitors with improved storage capacity and power density have been developed. The important factors affecting the performance of micro-supercapacitors are the intrinsic properties of electrode materials and electrolyte, architectural design of the device and the fabrication methods. This paper reviews the recent advances in fabrication of materials and devices and provides a critical analysis of reported performances of micro-supercapacitors.