Isostatic Pressing Research Articles

Enhanced magnetization jumps by GPa-level isostatic pressure in [α-Fe2O3]0.1[FeTiO3]0.9

Enhanced magnetization jumps by GPa-level isostatic pressure in [α-Fe2O3]0.1[FeTiO3]0.9

Effect of cellulase-assisted cold isostatic pressure extraction on the characteristics and functional properties of polyphenol extracts from camellia sinensis seeds

In this experiment, polyphenolic substances were extracted from Camellia sinensis seeds (CSS) using a synergistic treatment of cold isostatic pressure (CIP) and cellulase. The effects of pressure, treatment time, and cellulase addition on the experiment were investigated. And the optimal extraction conditions were established by single factor experiment and Box-benhken experiments: the pressure applied by CIP was 408.649 MPa, the treatment time was 10.995 min, and the cellulase addition was 4.098 %. The polyphenols in the extract were characterized and quantified using LC-MS/MS. By comparing the different treatments, it was found that the synergistic treatment of CIP and cellulase resulted in a higher extraction yield. FTIR, XRD and SEM mapping showed that CIP synergistic pretreatment with cellulase was able to disrupt the microstructure of the plant and promote the influx of the active ingredients into solution. Finally, the activity of the extracts was detected by using in vitro antioxidant experiments and RAW264.7 cellular anti-inflammatory experiments, which indicated that CIP and cellulase synergistically treated polyphenol extracts had high antioxidant and anti-inflammatory capacity. This experiment provides a new pretreatment method for extracting active substances from CSS.

Recovery of waste anode materials in solid oxide fuel cells

This study focuses on the recovery and recycling of production wastes from solid oxide cell (SOC) anode support manufacturing, specifically targeting the state-of-the-art NiO-YSZ (yttria stabilized zirconia) materials. A practical recovery strategy involving a burn-out process to remove additives is developed, followed by milling to manage grain growth and achieve desirable powder properties. The various reclaimed powders obtained after milling at different conditions are subsequently used to fabricate anode support microtubes through extrusion and tape casting coupled with isostatic pressing. Microtubular cells are also constructed on these supports. Comparative analyses of the mechanical and electrochemical performance, along with microstructural investigations, are conducted on supports and cells fabricated from both recovered and commercial powders. The findings indicate that anode supports fabricated from powders recovered through the suggested method exhibit flexural strengths and electrochemical performances comparable to those fabricated from commercial powders, thereby validating the effectiveness of the proposed recovery strategy.

Investigation of a sacrificial template material suitable for fabrication of anode support microtubes in microtubular solid oxide fuel cells

This study investigates the use of various sacrificial template materials in the form of a solid rod, including wood, carbon fiber, polyamide, resin and polylactic acid (PLA), for fabricating anode supports in microtubular solid oxide fuel cells (SOFCs) via tape casting and isostatic pressing. Anode support strips, produced via tape casting, are wound around these sacrificial rods. The rods are then burnout through co-sintering to yield microtubular anode supports. The results highlight PLA as a particularly promising material due to its balance of cost and performance. A novel rod design involving hollow PLA pipe is then explored to enhance the fabrication process. The anode support tape length or the wall thickness of anode support microtube is also considered. Microtubular cells are fabricated on the anode supports by dip coating other cell layers, and electrochemical and microstructural investigations are carried out. The final cell provides 0.365 W/cm2 maximum power density at 800 °C under 0.3 NL/min hydrogen flow and stationary air. Moreover, a patterned microtubular anode support is successfully fabricated using a 3D printed PLA tube featuring an array of dimples. The overall findings indicate that the proposed methodology not only simplifies the manufacturing process but also supports the feasibility of producing high-performance microtubular SOFCs with enhanced electrolyte-electrode interfaces through patterned anode designs.

Mn2+ doped aluminum-rich spinel transparent ceramic phosphor with higher performance for wide color-gamut backlight display

Due to the great potential of narrow-band green-emitting phosphors for wide color-gamut white light-emitting diodes (WLED) backlight displays, there is great interest in finding host materials with the desired luminescent properties and high quantum efficiency. Herein, a series of Mg0.98-xAl2(1+x/3)O4: 0.02Mn2+ (x = 0, 0.125, 0.25) powders were synthesized using high-temperature solid-phase reactions, followed by a combination of pressureless sintering and hot isostatic pressure sintering to fabricate transparent ceramic phosphors. The crystal structure refinement, NMR spectroscopy, and photoluminescence results show tetrahedral coordination of Mn2+ ions and an increase in cation vacancies and disorder with increasing x. These transparent ceramics exhibit narrow-band green emission, which shifts from 523 to 520 nm with increasing x. The Mg0.855Al2.08O4: 0.02Mn2+ ceramic sample has an in-line transmittance of over 80 % above 500 nm and internal quantum efficiencies as high as 96.2 %. The luminous intensity of the Mg0.855Al2.08O4: 0.02Mn2+ ceramic remains above 88.6 % at 425 K compared to room temperature, with a thermal conductivity of 12.4 W·m−1·K−1. A WLED device fabricated using the Mg0.855Al2.08O4: 0.02Mn2+ ceramic, K2SiF6:Mn4+ phosphors, and a blue chip show a wide color gamut of 126 % National Television System Committee standard. The results show that Mn2+-doped aluminum-rich spinel transparent ceramics have great potential for application in wide color gamut WLED backlight devices.

A review of near‐net shape forming by hot isostatic pressure technology

AbstractNear‐net shaping hot isostatic pressing (NNS‐HIP) forming process has the advantage of high material utilization ratio and good uniformity of billet microstructure. It is widely used to produce critical parts for harsh service environments in special fields such as aerospace and energy and chemical industry. This paper introduces the process characteristics and production flow of hot isostatic near‐net forming, the representative materials of hot isostatic near‐net forming, the development and application at home and abroad, and the micro‐ and macromodels of numerical simulation powder densification by HIP near‐net forming. Finally, the challenges and development trends of this technology are prospected, and corresponding countermeasures are put forward.

Diffusion of iron in zinc selenide during hot isostatic pressing

The diffusion of iron impurities in zinc selenide (ZnSe) during hot isostatic pressing (HIP) in the temperature range T = 1000–1300 °C and pressures P = 100–190 MPa has been investigated. The iron concentration and its distribution over the sample volume with a step from 20 to 50 μm was determined by IR spectroscopy in combination with an IR microscope. The diffusion coefficients of Fe in ZnSe at various temperatures and pressures were determined. The diffusion coefficients of Fe in ZnSe at P = 100 MPa and T = 1000 °C were (5.3 ± 0.6)x10−10 cm2/s, T = 1300 °C were (9.4 ± 0.9)x10−9 cm2/s. It is shown that the temperature dependences are described by the Arrhenius equation, and the isostatic pressure does not affect the value of the diffusion coefficients.

Beyond Traditional fuel cells: Development and a comprehensive analysis of mechanically Robust metal mesh-supported solid oxide fuel cell

At elevated operating temperatures, a large temperature gradient can cause irreparable damage to the solid oxide fuel cells (SOFCs) stack, eventually interrupting the durability of the stack. Metal substrate support could be used to overcome this challenge. However, the application of metal substrate support poses various challenges such as different thermal expansion coefficients, pore diameters, and complex fabrication techniques. Therefore, a first-ever novel and mechanically strong ferritic stainless-steel metal mesh-supported SOFC design is developed to mitigate these challenges. The metal mesh of 200 μm thickness is laminated with tape-casted green films of anode-support, anode functional layer (AFL), and electrolyte films of SOFC. The iso-static pressure of 300 MPa exhibits a firm attachment of the green films of SOFC with the metal mesh. Subsequently, the metal mesh-supported planar SOFC exhibits 3.3 times higher flexural strength compared to the conventional commercial anode-supported planar SOFC. The nano-CuO is added to constituent layers as a sintering aid to attain the maximum density at a lower sintering temperature of 1100 °C. The result shows that the practical application of the metal mesh-supported cell technology has a great potential to overwhelm the mechanical durability of SOFCs.

High-temperature microstructure evolution and thermal stability of SiCf/Ti60 composites

The microstructure evolution and thermal stability of continuous SiC fiber-reinforced Ti60 (SiCf/Ti60) composites at elevated temperatures have not been reported. The objective of this study was to conduct thermal exposure experiments of SiCf/Ti60 composites at 400 °C / 100 h, 600 °C / 100 h, and 800 °C / 100 h. The aim was to compare the interfacial and matrix microstructures under hot isostatic pressure (HIP) conditions and to assess their thermal stability. The results show that SiCf/Ti60 composites have excellent long-term thermal stability at 600 °C thermal exposure, short-term thermal stability at 800 °C thermal exposure and the thickness of the reaction layer (RL) increases to ∼1.27 μm. From HIP to 800 °C thermal exposure, RL changes from fine-grained TiC ║ discontinuous silicides ║ coarse-grained TiC to fine-grained TiC ║ near-continuous silicides ║ medium-grained TiC ║ coarse-grained TiC. Large-sized β-Ti and S2 silicides precipitated in the matrix at 800 ℃ thermal exposure, where β-Ti and α-Ti followed the Burgers orientation relationship (BOR), and the S2 exhibited a multitude of orientation relationships with both β-Ti and α-Ti. Furthermore, it was demonstrated that thermal exposure resulted in a reduction in the dislocation density of the matrix. In particular, thermal exposure at 800 °C led to a decrease in the dislocation density of the matrix by ∼47 %. This observation provided a novel approach for the reduction of crystal defects in the matrix and the enhancement of the properties of SiCf/Ti composites.

Study on efficient extraction of saponins from Polygonatum sibiricum by enzyme assisted cold isostatic pressing technology

Saponin is one of the main active ingredients of Polygonatum sibiricum. In this study, the method of enzyme-assisted cold isostatic pressure extraction (EACIP) of Polygonatum sibiricum saponins was established. The effects of different cold isostatic extraction pressures, pressure-maintaining time times, enzymatic temperatures and enzymatic pH on the yield of saponin were investigated, and the factors were simplified by single factor experiments and Box-benhken design (BBD). Under the best extraction conditions, the EACIP method achieved the best possible results and extraction rate was 11.45 % ± 0.017. In addition, SEM-Mapping, XRD analysis and FTIR analysis proved that EACIP treatment increased the extent of cell deformation and improved the mass transfer system between solvent and active substance. Furthermore, by comparing different extraction methods, EACIP was found to have a higher extraction rate due to the synergistic effect of cold isostatic pressure extraction (CIP) and enzymatic hydrolysis extraction (EH). In vitro antioxidant and anti-inflammatory assays demonstrated that EACIP extracts have good antioxidant and anti-inflammatory capacity. Therefore, EACIP is a method to extract natural products from plants with increased extraction rate.

Simultaneously enhanced strength and plasticity of laser powder bed fused tantalum by hot isostatic pressing

The effects of hot isostatic pressure (HIP) treatment (850 °C/1350 °C, 150 MPa, 4 h) on the microstructure and mechanical properties of laser powder bed fused tantalum were investigated. The results show that the heat treatment process with high pressure and low temperature (relative to the melting point) limited the growth of tantalum grain size and homogenized the microstructure. The hot isostatic pressure of 850 °C/1350 °C and high pressure of 150 MPa promote plastic deformation in the pore region of the laser powder bed fused tantalum and reduce the pore size, thus increasing the sample densities to more than 99 %. After 1350-HIP, all the properties of laser powder bed fused tantalum are significantly improved, and the hardness, ultimate tensile strength, and elongation of tantalum are further improved to 273 HV (40.72 %), 551 MPa (16.24 %), and 43.4 % (18.26 %).

Analysis of Mechanical Properties of Recycled Carbon Fiber Reinforced Plastic using Isostatic Pressure

Analysis of Mechanical Properties of Recycled Carbon Fiber Reinforced Plastic using Isostatic Pressure

Impact of Vertex Functionalization on Flexibility of Porous Organic Cages.

Efficient carbon capture requires engineered porous systems that selectively capture CO2 and have low energy regeneration pathways. Porous liquids (PLs), solvent-based systems containing permanent porosity through the incorporation of a porous host, increase the CO2 adsorption capacity. A proposed mechanism of PL regeneration is the application of isostatic pressure in which the dissolved nanoporous host is compressed to alter the stability of gases in the internal pore. This regeneration mechanism relies on the flexibility of the porous host, which can be evaluated through molecular simulations. Here, the flexibility of porous organic cages (POCs) as representative porous hosts was evaluated, during which pore windows decreased by 10-40% at 6 GPa. POCs with sterically smaller functional groups, such as the 1,2-ethane in the CC1 POC resulted in greater imine cage flexibility relative to those with sterically larger functional groups, such as the cyclohexane in the CC3 POC that protected the imine cage from the application of pressure. Structural changes in the POC also caused CO2 adsorption to be thermodynamically unfavorable beginning at ∼2.2 GPa in the CC1 POC, ∼1.1 GPa in the CC3 POC, and ∼1.0 GPa in the CC13 POC, indicating that the CO2 would be expelled from the POC at or above these pressures. Energy barriers for CO2 desorption from inside the POC varied based on the geometry of the pore window and all the POCs had at least one pore window with a sufficiently low energy barrier to allow for CO2 desorption under ambient temperatures. The results identified that flexibility of the CC1, CC3, or CC13 POCs under compression can result in the expulsion of captured gas molecules.

Room-temperature pressure-induced phase separation in glassy alloys

Understanding the structural evolution of glass-forming alloys (metallic glasses) under high pressure conditions is important, on one hand, for elucidating their phase stability, and on the other, for manipulating their structure and properties. In this study, we investigate the unique pressure-induced effect leading to the phase separation phenomenon in glassy alloys, the effect which was not observed in the earlier works. By subjecting the system to various levels of external isostatic pressure, we observed the emergence of a distinct phase-separated structure within some glassy alloys. Our results shed light on the underlying mechanisms of phase separation in glassy alloys under extreme pressure conditions, providing valuable information for possible control of their structure and properties. This demonstrates that pressure can be used along or instead of temperature to produce nano-structured polyphase metallic glasses.

A high-pressure isostatic lamination technique to fabricate versatile carbon electrode-based perovskite solar cells

Perovskite solar cells (PSCs) with evaporated gold (Au) electrodes have shown great efficiencies, but the maturity of the technology demands low-cost and scalable alternatives to progress towards commercialisation. Carbon electrode-based PSCs (C-PSCs) represent a promising alternative, however, optimising the interface between the hole transport layer (HTL) and the carbon electrode without damaging the underlying functional layers is a persistent challenge. Here, we describe a lamination technique using an isostatic press that can apply exceedingly high pressure to physically form an HTL/carbon interface on par with vacuum-evaporated electrodes, without damaging the device. Research-scale C-PSCs with a power conversion efficiency (PCE) of up to 20.8% are demonstrated along with large-area C-PSCs with PCEs of 19.8% and 16.9% for cell areas of 0.95 cm2 and 5.5 cm2, respectively. The unencapsulated C-PSCs significantly outperform the Au-electrode devices in accelerated operational stability testing (ISOS-L-1), retaining 84% of the initial PCE after 1000 h. Additionally, this versatile technique is also used to fabricate flexible, roll-to-roll printed C-PSCs with efficiencies of up to 15.8%.

Bovine hydroxyapatite/3Y-TZP bioceramic: Aligning 3Y-TZP content with sintering parameters

This study aimed to produces and characterize bovine hydroxyapatite (HA) bioceramic with 3Y-TZP addition and analyze different sintering curves. HA was extracted from bovine bones and nanoparticulated. HA discs (0, 1, 5 and 10 wt% 3Y-TZP) were subjected to uniaxial and isostatic pressing. Dilatometry analysis was performed and the groups were sintered using 3 different firing curves (conventional, 1300 °C; 2-step, 1292 °C; 2-step, 1420 °C). The samples were analyzed by X-ray diffraction (XRD), biaxial flexural strength (BFS), Vickers microhardness (VH) and Field emission scanning electron microscopy (FE-SEM). The dilatometry results signaled the need for sintering optimization in groups added with 3Y-TZP. XRD demonstrated the characteristic crystallographic peaks of HA in the pure groups and with 1% 3Y-TZP, and decomposition of HA into β-TCP and formation of calcium zirconate in the groups with 5 and 10% 3Y-TZP. Considering each composition, the groups of pure HA (131.3 ± 13.5 MPa; 401 ± 12.7 GPa) sintered by the conventional curve and HA+1%3Y-TZP (145 ± 8.6 MPa; 507 ± 47.9 GPa), HA+5%3Y-TZP (68.1 ± 14.2 MPa; 183 ± 9.8 GPa) and HA+10%3Y-TZP (55.6 ± 5.1 MPa; 96.1 ± 7.64 GPa) sintered by the 2-step curve at 1420 °C, combined the best BFS and VH results. The addition of 1 wt% 3Y-TZP and optimization in the sintering process improved the mechanical and microstructural properties of HA bioceramics and maintenance of its crystalline characteristics. Refinement in material processing is necessary for the future use of this bioceramic in dentistry.

Boosting the performance of bolt-microtubular solid oxide fuel cells through surface pattern tuning

A number of bolt-microtubular anode supports (BMASs) are manufactured by winding the corresponding thin tapes on threaded rods of different thread pitches and depths, followed by co-lamination using isostatic press. Bolt-microtubular cells (BMCs) are also constructed on BMASs to investigate the effects of the created surface patterns on the cell performance and microstructure. The bolt-microtubular cell, whose anode support is patterned by using a threaded rod with 0.8 mm thread pitch and 0.4 mm thread depth, exhibits ∼92% higher maximum performance than that of the reference cell at 800 ºC under 0.3 NL/min hydrogen flow and stagnant air. The almost doubled performance is mainly due to the increase in anode-electrolyte and cathode-electrolyte interfacial areas by the surface patterns created. The cell is also subjected to a 200-h life test at 800 °C and 0.7 V and demonstrates a stable performance.

Microstructure and surface morphology change of hydrogenated diamond-like carbon coating with gradient Cr and Si under high temperature and high pressure

A series of annealing treatments were designed to investigate the microstructure structure and surface morphology of hydrogenated diamond-like carbon coating with gradient Cr and Si (DCrSi) in different environments (argon & isostatic pressure) at different temperatures (400°C, 500°C, and 600°C). The pressure effect on the stability of DCrSi coatings was deduced from the analysis of the microstructure structure and surface morphology by using scanning electron microscopy (SEM), surface roughness test, and Raman spectroscopy. The experiment results show that no apparent change to the layer structure can be found in the argon annealed and HIPped coatings. Similar to argon annealed coatings, with increasing HIPping temperature, the surface roughness of coatings increases, and the sp3 content of the coatings reduces. The relatively low roughness of the HIPped surfaces compared with the argon annealed ones could be attributed to the delayed transformation from sp3 carbon bonding to sp2 carbon bonding (i.e., graphitization) by high pressure. Compared with Si-free DCr coating, for Si-containing DCrSi coatings, Si bonded with C from broken C-H bonding and C-C bonding to form SiC quasi compound. Adding silicon into DLC can increase the density of the coatings.

A novel sensor with excellent high-temperature performance for in-situ temperature measurement

Real-time access to critical information about system temperature variations is essential for evaluating system performance in some of the high-temperature and harsh environments. Given the technical difficulty of accurately obtaining the temperature of a high-temperature and harsh environment, a new sensor package structure is proposed. Combining ceramic sintering and isostatic pressure molding methods, the thermal junction is fixed in the temperature measurement end face of the alumina ceramic substrate, while the shell design threads play a role in fixing the sensor and preventing loosening. This paper conducted repeatability, upper-temperature limit, and high-temperature serviceability assessment tests on the sensor. The results show that the sensor maximum repeatability error is 2.4%. The sensor can continue to operate at 1200°C for more than 6 hours with no signal interruption and the upper limit of temperature measurement is 1307°C. The results demonstrate the feasibility and practicality of temperature measurement by this sensor in high-temperature and harsh environments.

Effect of hot isostatic pressure on the microstructure and tensile properties of γ′-strengthened superalloy fabricated through induction-assisted directed energy deposition

Effect of hot isostatic pressure on the microstructure and tensile properties of γ′-strengthened superalloy fabricated through induction-assisted directed energy deposition