Thermo-mechanical Durability Research Articles

Integration of metal co-dopted cysteine builted in porous covalent organic framework (COF) decorated 2D hexagonal boron nitride (h-BN) for multi-functional smart coatings

Advanced multi-functional epoxy coating with physical barrier/shielding against corrosive species, self-repairing-capability/active anti-corrosive behavior, abrasion resistance, and thermomechanical durability was established in this study. For this purpose, zinc/l-cysteine (ZC) inbuilt pH-sensitive covalent organic framework (COF) decorated two dimensional (2D) layered amino-functionalized (Si) oxidized hexagonal boron nitride (ZC-COF-Si-Oh-BN) container was prepared. Different analyses such as FT-IR, XRD, BET, XPS, TGA, TEM, and FE-SEM were utilized to evaluate the synthesized containers and pristine materials. To figure out the function of entry of the ZC-COF-Si-Oh-BN container into the epoxy coating (EC/ZC-COF-Si-Oh-BN), the EIS, salt spray (SS), cathodic disbondement (CD), pull-off adhesion, Taber abrasion, and dynamic mechanical thermal analysis (DMTA) tests were employed. The results revealed that the introduction of the ZC-COF-Si-Oh-BN container into the neat epoxy polyamide coating (EC) improved the physical barrier protection with a value of log |Z| 10mHz equal to 10.22 even after too long soaking time of 112 days in the saline solution (3.5 wt% of sodium chloride), and recovery-capability/active anti-corrosive behavior with 20.6 % healing degree after 7 h of soaking time. The abrasion weight loss for the EC and EC/ZC-COF-Si-Oh-BN coatings after 2000 abrasion cycles was about 4.8, and 4.1 mg, respectively, with 14.5 % improvement in abrasion resistance.

Simulating Combustion-Induced Noise from a Gas-Fired Water Heater

Residential and commercial gas water heaters are designed for optimal performance for different operating conditions. These differences could arise from regional changes in fuel, local regulations for emissions, and the temperature preferences of the customer. From an engineering perspective apart from performance, other issues such as fire safety, longevity (thermo-mechanical durability) and though rarely, noise and vibration (N & V) need to be addressed. Unlike other appliances, there are almost no moving mechanical parts in an atmospheric gas water heater. This makes the N & V problem an interesting engineering challenge to diagnose and fix. In this paper, the authors consider different hypotheses for understanding the origins of combustion-induced noise. They propose a hybrid simulation methodology to predict noise and finally present the sound pressure level comparison with the physical test.

Study on ZrSi2 as a Candidate Material for Extreme Ultraviolet Pellicles.

An extreme ultraviolet (EUV) pellicle is an ultrathin membrane at a stand-off distance from the reticle surface that protects the EUV mask from contamination during the exposure process. EUV pellicles must exhibit high EUV transmittance, low EUV reflectivity, and superior thermomechanical durability that can withstand the gradually increasing EUV source power. This study proposes an optimal range of optical constants to satisfy the EUV pellicle requirements based on the optical simulation results. Based on this, zirconium disilicide (ZrSi2), which is expected to satisfy the optical and thermomechanical requirements, was selected as the EUV pellicle candidate material. An EUV pellicle composite comprising a ZrSi2 thin film deposited via co-sputtering was fabricated, and its thermal, optical, and mechanical properties were evaluated. The emissivity increased with an increase in the thickness of the ZrSi2 thin film. The measured EUV transmittance (92.7%) and reflectivity (0.033%) of the fabricated pellicle satisfied the EUV pellicle requirements. The ultimate tensile strength of the pellicle was 3.5 GPa. Thus, the applicability of the ZrSi2 thin film as an EUV pellicle material was verified.

Development of highly efficient and durable large-area solid oxide fuel cell by a direct-ink-writing three-dimensional printer

The commercialization of efficient and durable solid oxide fuel cells is hugely hindered due to the expensive and complex fabrication process. In this regard, the additive manufacturing technique, i.e., three-dimensional printing (3-D printing), has gained tremendous attention because of its ability to fabricate tunable functional ceramic layers with cost-effectiveness and mass customization. Therefore, in this work, the anode (NiO-ScSZ) and cathode (LSM) of the large-area SOFC (5 × 5 cm2) are printed using a direct-ink-writing (DIW) printer. The anode-functional and electrolyte layers are coated by spray and spin coating. The viscosity of the optimized anode and cathode inks are 5.85 Pa s and 0.97 Pa s, respectively. The electrochemical impedance and the performance of 3D-SOFC are investigated by supplying hydrogen and air. The maximum power density of the cell is 368 mW cm−2 at 800 °C. However, by inserting a hybrid scandia stabilized zirconia layer by spraying followed by magnetron sputtering onto the AFL, the electrochemical performance of the cell is significantly (21%) enhanced; the peak power density is 442 mW cm−2, and the corresponding polarization resistance is 0.267 Ω cm2 at 800 °C. Furthermore, the long-term cell test under galvanostatic mode (j = 0.5 A cm−2) at 700 °C for 100 h and thermal cycling between 400 and 700 °C concludes that the 3D-SOFC exhibits exceptional stability with a voltage loss of 0.845% h−1 and thermomechanical durability.

Evaluation of Three-Dimensional Placement of Built-in Catalytic Partial Oxidation Catalyst in an Anode-Supported Honeycomb SOFC

Honeycomb solid oxide fuel cells (SOFCs) can achieve high power density with improved thermo-mechanical durability at high temperatures [1]. In this study, a compact SOFC with catalytic partial oxidation reforming catalyst embedded in the flow channels of a porous honeycomb anode support has been fabricated and evaluated. I-V measurements and gas chromatography for the outlet gas were carried out while methane/air mixture gas was fed as fuel. I-V measurements were performed to compare the performance of the two configurations: one with fuel supplied from the central channel and discharged from the surrounding four channels, and the other with fuel supplied from the four channels and discharged from the central channel. As a result, the effect of concentration overpotential was smaller in the latter case. The gas chromatograph detected hydrogen in the reformed gas for both cases.AcknowledgmentsThanks are offered to Professor Kohei Ito of Kyushu University for valuable discussions.References H. Nakajima, S. Murakami, S. Ikeda, and T. Kitahara, Heat Mass Transfer, 54, 2545 (2018).

Evaluation of Three-Dimensional Placement of Built-in Catalytic Partial Oxidation Catalyst in an Anode-Supported Honeycomb SOFC

Honeycomb solid oxide fuel cells (SOFCs) can achieve high volumetric power density with improved thermo-mechanical durability at high temperatures. In this study, a compact SOFC with catalytic partial oxidation reforming catalyst embedded in the flow channels of a porous honeycomb anode support has been fabricated and evaluated. Current-voltage (I-V) measurements and gas chromatography for the outlet gas were carried out while methane/air mixture gas was fed as fuel. I-V measurements were performed to compare the performance of two flow channel configurations: one with fuel fed to the central channel having a built-in reformer and discharged from surrounding four channels, and the other with fuel fed to the four channels with the reformer and discharged from the central channel. As a result, the concentration overpotential was smaller in the latter case. The gas chromatography detected hydrogen in the reformed gas at the outlets of both cases.

Fabrication and Evaluation of an Anode-Supported Honeycomb SOFC with Built-in Catalytic Partial Oxidation Micro-Reformer

Honeycomb solid oxide fuel cells (SOFCs) can achieve high power density with improved thermo-mechanical durability at high temperatures [1]. In this study, a compact SOFC with catalytic partial oxidation (CPOX) reforming catalyst [2, 3] embedded in the flow channels of the porous honeycomb anode support was fabricated and evaluated. I-V measurements and gas chromatography analyses for the outlet gas were carried out while methane/air mixture gas was fed as fuel. The gas chromatograph detected hydrogen in the reformed gas. Temperature distribution in the cell was also measured.AcknowledgmentsThe authors are indebted to Professor Kohei Ito of Kyushu University for valuable discussions. References H. Nakajima, S. Murakami, S. Ikeda, and T. Kitahara, Heat and Mass Transfer, 54, 2545 (2018). A. J. Santis-Alvarez, M. Nabavi, B. Jiang, T. Maeder, P. Muralt, and D. Poulikakos, Chemical Engineering Science 84, 469 (2012). W. Matsunaka, H. Nakajima, A. J. Santis-Alvarez, D. Poulikakos, and K. Ito, The Proceedings of Conference of Kyushu Branch, The Japan Society of Mechanical Engineers, 71, F21, 2018.

Fuel inventory and impurity deposition in castellated tungsten tiles in KSTAR: experiment and modelling

Plasma-facing components have castellated structure for thermo-mechanical durability and integrity under high heat flux loads. However, fuel co-deposition in the grooves of the castellation may enhance fuel retention. In KSTAR, castellated tungsten tiles were tested to investigate the impact of tile shaping and misalignment on the retention. The tiles with poloidal and toroidal gaps of 0.5 mm were exposed at the divertor during a whole campaign encompassing 4364 s of plasma operation. Surfaces inside the gaps were analysed by means of 3He-based micro-NRA, ERDA and PIXE. Modelling of carbon deposition was performed with the impurity transport code 3D-GAPS assuming impurity penetration along the magnetic field lines with plasma-wetted areas defined by simple geometrical shadowing. The main deposited element is carbon with different concentration at the entrance of the groove, dependent on the tile shaping: 6 × 1017 cm−2 for a chamfered and misaligned gap and up to 283 × 1017 cm−2 for a flat and aligned gap. The deposition patterns are exponentially decreased to 4–10 × 1016 cm−2 inside the gap. Deuterium concentration in the gaps described above ranges, respectively, from 2 × 1017 cm−2 to 50 × 1017 cm−2 at the top of the groove and decreases to 1–4 × 1016 cm−2 following the carbon deposition trends. The highest carbon and deuterium densities are measured at the plasma-exposed side of the flat tile and aligned gap. Modelled deposition profiles reproduce qualitatively the experimentally observed trends.

Integrated atomic quantum technologies in demanding environments: development and qualification of miniaturized optical setups and integration technologies for UHV and space operation

Employing quantum sensors in field or in space implies demanding requirements on the used components and integration technologies. Within our work on compact atomic sensors, we develop miniaturized, ultra-stable optical setups for optical cooling and trapping of cold atomic gases on atom chips. Besides challenging demands on alignment precision and thermo-mechanical durability, we specifically address ultra-high vacuum (UHV) compatibility of our adhesive integration technology and the assembled optical components. A prototype of an UHV-compatible, crossed beam optical dipole trap at 1064 nm for application within a cold rubidium atomic quantum sensor currently in development at the Joint Lab Integrated Quantum Sensors at Ferdinand-Braun-Institut, Leibniz-Institut fur Hochstfrequenztechnik is described. We describe the design and first qualification efforts on adhesive micro-integration technologies. These tests are conducted in application-relevant geometries and material combinations common for micro-integrated optical setups. Adhesive aging will be investigated by thermal cycling and radiation exposure. For vacuum compatibility testing, a versatile UHV testing system for samples up to $$65\times 65\,\text{mm}^2$$ footprint is currently being set up, enabling residual gas analysis, temperature cycling up to $$200\,^{\circ }\text{C}$$ and measurement of total gas rates down to expected $$5\times 10^{-10}\,\text{mbar}\,\text{l/s}$$ at a base pressure of $$10^{-11}\,\text{mbar}$$, exceeding the common ASTM E595 test.

Three-dimensional flow channel arrangements in an anode-supported honeycomb solid oxide fuel cell

An anode-supported honeycomb SOFC can achieve high volumetric power density and improve thermo-mechanical durability at high temperatures. We have so far fabricated a honeycomb cell with a cathode layer made of La0.7Sr0.3MnO3 (LSM) and an electrolyte layer of 8YSZ on a porous anode support in the honeycomb form of Ni/8YSZ. In the present study, current-voltage and volumetric power density characteristics of the cells having different anode/cathode flow channel arrangements are measured under different flow rates of fed hydrogen to show the effect of three-dimensional fuel transport and distribution in the porous anode support on the cell performance. Ohmic resistances of the cells varying with current is also evaluated to clarify the nickel re-oxidation of the anode support by fuel depletion depending on the anode flow channel arrangements. We thereby discuss the difference of the advantage between the flow channel arrangements depending on the flow rate of the fed fuel to choose more suitable operation mode.

Enhancement of fuel transfer in anode-supported honeycomb solid oxide fuel cells

An anode-supported honeycomb solid oxide fuel cell can achieve high volumetric power density and improve thermo-mechanical durability at high temperatures. We have so far shown the promising power densities and investigated the effect of flow channel configurations on the cell performance in terms of the hydrogen partial pressure distributions in the cell under operation. In the present study, current-voltage characteristics of the cell depending on thicknesses of the porous anode substrate and forced convection in the substrate are studied under different flow rates of fed hydrogen to clarify the effect of 3-dimensional fuel transport in the porous anode substrate on the cell performance.

Mass Transfer in an Anode-Supported Honeycomb Solid Oxide Fuel Cell

An anode-supported honeycomb SOFC can achieve high volumetric power density and improve thermo-mechanical durability at high temperatures. We have so far fabricated the honeycomb cell with a cathode layer made of La0.7Sr0.3MnO3 (LSM) and an electrolyte layer of 8YSZ on a porous anode substrate in honeycomb form of Ni/8YSZ. In the present study, current-voltage characteristics of the cells having different porous substrate thicknesses and anode/cathode flow channel configurations are studied under different flow rates of fed hydrogen to clarify the effect of 3-dimensional fuel transport in the anode porous substrate on the cell performance. We also estimate the hydrogen mole fraction distributions in the honeycomb cell with different anode substrate thicknesses using the finite element method, and discuss appropriate porous anode substrate thickness.

Mass Transfer in an Anode-Supported Honeycomb Solid Oxide Fuel Cell

An anode-supported honeycomb SOFC can achieve high volumetric power density and improve thermo-mechanical durability at high temperatures. We have so far fabricated the honeycomb cell with a cathode layer of LSM and an electrolyte layer of 8YSZ on a porous anode honeycomb substrate of Ni/8YSZ. The anode-supported honeycomb cell exhibited promising volumetric power densities. Effect of flow channel configurations on the cell performance was investigated in terms of the hydrogen partial pressure distribution in the cell under operation as well[1]. In the present study, current-voltage and current-power density characteristics of the cells having different porous substrate thicknesses and anode/cathode flow channel configurations are studied under different flow rates and partial pressures of fed hydrogen. We also investigate performance changes by forced hydrogen flow through the porous anode substrate taking advantage of valves connected to each outlet of the honeycomb cell.ReferenceS. Kotake, H. Nakajima, and T. Kitahara, “Flow Channel Configurations of an Anode-Supported Honeycomb Solid Oxide Fuel Cell” ECS Trans., 57(1), B815 (2013).

Performance of an Anode-Supported Honeycomb Solid Oxide Fuel Cell

An anode-supported honeycomb solid oxide fuel cell can work with high power density and improve thermo-mechanical durability at high temperatures. We have thus fabricated the honeycomb cell with an electrolyte layer of 8YSZ on an anode honeycomb substrate of Ni/8YSZ. The cathode layer is LSM-YSZ composite. Current-voltage and current-power density characteristics of the cells having different anode and cathode flow channel configurations are measured under different hydrogen flow rates. We also evaluate the hydrogen mole fraction distributions in the honeycomb cell using finite element method, and discuss appropriate anode and cathode flow channel configurations. The present study is a starting point of developing an anode-supported honeycomb cell for cell stacks assembled with multiple and large scale honeycomb cells which can achieve high efficiency flow channel and current collecting configurations, and enhanced thermo-mechanical durability.

H112 燃料極支持ハニカム固体酸化物形燃料電池内の物質輸送解析

An anode-supported honeycomb SOFC can achieve high volumetric power density and improve thermo-mechanical durability at high temperatures. We have so far fabricated the honeycomb cell with a cathode layer of LSM and an electrolyte layer of 8YSZ on a porous anode honeycomb substrate of Ni/8YSZ. The anode-supported honeycomb cell exhibited promising volumetric power densities. In the present study, current-voltage and current-power density characteristics of the cells having different porous substrate thicknesses and anode/cathode flow channel configurations are studied under different flow rates and partial pressures of fed hydrogen to clarify the effect of fuel transport in the anode porous substrate.

Flow Channel Configurations of an Anode-Supported Honeycomb Solid Oxide Fuel Cell

An anode-supported honeycomb SOFC can achieve high power density and improve thermo-mechanical durability at high temperatures. We have fabricated the honeycomb cell with an electrolyte layer of 8YSZ on an anode honeycomb substrate of Ni/8YSZ. The cathode layer is LSM-YSZ composite. Current-voltage and current-power density characteristics of the cells having different anode and cathode flow channel configurations are measured under different hydrogen flow rates and partial pressures. We also evaluate the hydrogen mole fraction distributions in the honeycomb cell using finite element method, and discuss appropriate anode and cathode flow channel configurations.

New technique for increasing the high-temperature durability of aluminium pistons

The temperatures and pressures in modern day diesel engines are climbing steadily. As a result and in order to have adequate reserves of strength aluminium pistons must feature improved high temperature thermo-mechanical durability. With its DuraBowl technology, the local post-treatment of highly loaded piston regions, Federal-Mogul has been able to increase piston service life by a factor of between four and eight.

Interaction Effect of Voids and Standoff Height on Thermomechanical Durability of BGA Solder Joints

This paper documents simulation studies on the interactive effect of standoff height and void volume on the thermomechanical durability of ball-grid-array solder joints using a 3-D viscoplastic finite element analysis. Surface Evolver software was used to find the optimized shape of the solder joints and standoff height by minimizing the surface energy as voids with different sizes were placed in solder balls. A global-local modeling approach was then utilized to model the thermomechanical durability of voided solder joints. Void-area-fraction ranges of 14%-40% were analyzed. A nonmonotonic behavior of durability versus void area fraction was observed. The results showed that, if the void is completely inside the solder ball and has no interface with the boundaries of the joint, it does not have a detrimental effect and even improves the durability as the void size increases. However, voids located at the interface of the solder joint and copper pads were found very detrimental to durability. Factors such as load bearing area, stress concentration factor, and overall compliance of the structure were found responsible for the nonmonotonic behavior of the joints. An analytical micromechanics approach was used to calculate the compliance of the structure, and a nonmonotonic trend in phase with the durability trend was observed. The stress concentration factor also showed the same nonmonotonic trend. The rise of these two factors for the void interfacing with copper pads in addition to the decreased-load-bearing-area effect resulted in a drastic decrease in durability.

Numerical analysis of thermo-mechanical reliability of through silicon vias (TSVs) and solder interconnects in 3-dimensional integrated circuits

Three-dimensional integrated circuit (3D IC) is a promising technology in today's IC packaging industry. Since the technology is in infancy stages, many aspects of this technology are still under heavy investigation. Reliability of through silicon via (TSV) interconnects and interlayer bondings between the silicon layers are issues that become more complicated in 3D ICs due to the complexity of the architecture and miniaturized interconnect. Optimizing design of these devices is essential in order to avoid short fatigue life of interconnects. This manuscript addresses the impact of design parameters such as die thickness, TSV diameter and pitch, and underfill thickness and properties on thermo-mechanical durability of direct chip attach (DCA) solder joints and TSV interconnects used in a 3D IC packages. A design was proposed where DCA is used to connect four layers of ICs and TSVs are used to connect the active layer of the dies to the second silicon layer. Solder joints, as small as [email protected] diameter, were used to attach silicon layers. A numerical experiment is designed to vary these factors at three levels using L9 orthogonal array. A 3-dimensional model of the package was built and model was solved under an accelerated thermal cycle loading. Solder is considered to be visco-plastic material and copper interconnects are assumed to follow bi-linear isotropic hardening behavior. Two continuum damage models; energy-partitioning (E-P) and Coffin-Manson; were used to assess the number of cycles to failure for solder joints and TSV copper interconnects, respectively. Minitab software was used to analyze the result of experiment and general linear model analysis of variance (GLMANOVA) was used to evaluate significance of each factor. The most influential factors on durability of solder interconnect are found to be underfill properties and height. However, the most influential factor on TSV durability is found to be TSV diameter. A non-linear response was observed for TSV pitch and diameter indicating that the optimum level is in the range selected. Location of failures was also found to depend on selected parameters and be a function of effective CTE. A simple analytical approach is presented to estimate the effective CTE for silicon layers containing TSVs. Effective CTE can be varied as one of the design parameters to achieve optimum design.

Iridium Coatings with Titanium Sub‐Layer Deposited by RF Magnetron Sputtering: Mechanical Properties and Contact Behavior with RoHS‐Compliant Glass Melt

AbstractIn this contribution, we report on the mechanical properties of iridium coatings with titanium sub‐layer deposited by RF magnetron sputtering. Measurements of the coating adhesion were performed with scanning scratch test. The microhardness and effective Young's modulus were determined by nanoindentation test. In order to evaluate the suitability of the coating for glass molding applications, the contact behavior with a hot melt of a RoHS‐compliant glass type was investigated. It was observed that iridium coatings with titanium sub‐layer deposited on tungsten carbide substrates exhibited excellent thermomechanical durability. Furthermore, the coating was chemically resistant against the hot glass melt since no degradation of the coating's surface was observed after 5000 cyclic contacts with hot P‐LaSF47 glass melt.