Ceramic Heat Research Articles

A Ceramic Heat Flux Sensor With High Sensitivity for Ultrahigh Temperature

A Ceramic Heat Flux Sensor With High Sensitivity for Ultrahigh Temperature

Evaluation of Hair Changes and Damage According to Hair Iron Heating Plate Material

This study investigates the effects of ceramic and polymer heating plates on the surface and structure of hair. To evaluate the degree of hair damage caused by the iron and polymer heating plate materials, hair moisture content and the degree of hair fading were measured using Thermo Gravimetric Analysis (TGA) and a colorimeter, respectively. Additionally, a Scanning Electron Microscope (SEM) was used to analyze the change in the microstructure of the hair. As a result, hair treated using a polymer iron contained significantly higher moisture than hair treated using a ceramic iron. The colorimeter analysis showed that ceramic irons caused fading and damage to hair color, whereas polymer irons did not. Lastly, hair treated with a ceramic flat iron had extensive surface scratches and cuticle melting from the SEM analysis, unlike hair treated with a polymer iron, which preserves superior hair shape and cuticle integrity.

Influence of solid loading on microstructure evolution and thermal conductivity of aluminum nitride ceramics fabricated by digital light processing 3D printing

Efficient thermal management is essential to reduce hot spot temperature of high-power opto-electronic components and improve their working efficiency. In this work, AlN ceramics with high density and thermal conductivity properties were fabricated using a joint process of digital light processing (DLP) 3D printing and micro-pressure-assisted sintering method. Effects of solid loading on microstructure evolution and thermal properties of the ceramics were systematically discussed. AlN ceramic mini-channel heat sinks were designed and fabricated using the optimized DLP 3D printing and sintering parameters. The thermal management performances of the ceramic heat sinks were evaluated by investigating the optoelectronic property of the encapsulated laser diode module. Results indicated that the laser diode module could be long-timely operated at full driven power. This study provided a new strategy for fabricating high performance AlN ceramics with complex configurations and highlighted the technical potential of AlN ceramic heat sink with compact coolant channels.

Vat photopolymerization of complex-shaped silicon nitride ceramics with high mechanical and thermal performance by optimization sintering aids and kinetics

In this study, the impact of sintering aid content and sintering time on the density, phase composition, microstructure, thermal conductivity, and mechanical properties of silicon nitride (Si3N4) ceramics through vat photopolymerization (VPP) was systematically investigated. The results revealed that an increase in sintering aid amount promoted the network distribution of the grain boundary phase along with densification, grain coarsening and microstructure uniformity. The extension of sintering time improved density, thermal conductivity, and mechanical properties of the material. Superior performance with relative density of 99.4 %, thermal conductivity of 64.4 W·m−1·K−1, flexural strength of 879 ± 37 MPa, and hardness of 15.0 ± 0.4 GPa was achieved in sample containing 8 wt% MgO/Y2O3 sintered for 12 h. Finally, high-precision Si3N4 ceramic heat sink elements were successfully fabricated via VPP, opening up new prospects in thermal management applications associated with electronics and automotive industries.

Enhancing oxidation resistance of silicon nitride using a Ca2+ stabilizer

Silicon nitrides are widely used in ceramic heaters for combustion engines due to their high strength and wear resistance. However, their poor oxidation resistance at elevated temperatures limits their reliability. Oxidation products, such as silica and intermediate compounds from sintering additives, often suffer from microcracks due to phase transformation and volume expansion mismatch during thermo-mechanical cycles. Use of cation dopants to chemically stabilize the transformation of the oxidation front is proposed. This study investigated the effect of Ca2+ treatment on Si3N4 with MgO and Y2O3 sintering aids. The Si3N4 samples were coated with CaO and the phase composition, microstructure, and chemical distribution of the oxidation products were analyzed using XRD, SEM, TEM, STEM, and EDS. The oxidation coupon tests revealed that the CaO coating effectively protected Si3N4 from oxidation at 1300 ºC for 40 h. Moreover, the microstructural analysis showed that CaO coating created more favorable microstructures which reduced oxidation reactions.

Heat wave impacts on crop‐pest dynamics are dependent upon insect ontogeny and plant resistance

AbstractHeat waves, brief periods of unusually high temperatures, are damaging to agroecosystems and are increasing in frequency and intensity due to climate change. Despite growing appreciation for the threat that heat waves pose to agricultural sustainability, we have a poor understanding of what determines their impact on agroecological interactions in the field. Here, we report the results of a field experiment that examined how heat waves and their timing interact with crop pest resistance to influence the interactions between potato (Solanum tuberosum) and its most damaging pest, the Colorado potato beetle (CPB; Leptinotarsa decemlineata). We used open‐top chambers and ceramic heaters to generate heat wave conditions in field plots with pest‐resistant and pest‐susceptible potato varieties at four CPB developmental stages. We then assessed CPB performance, leaf herbivory, and tuber yield. The neonate‐stage heat wave reduced larval survival by 10%, but the surviving larvae were 18% larger and developed 15% faster. However, these effects occurred only on the susceptible variety; both larval survival and growth were unaffected by the heat wave in the pest‐resistant variety. Moreover, the neonate‐stage heat wave reduced adult survival by 15%, suggesting negative carry‐over effects of early‐life heat exposure. Heat wave events after the neonate stage had no effects on CPB performance, crop damage, or tuber yield. Our results indicate that timing and pest resistance in crops are essential for understanding the impacts of extreme heat events on crop‐pest dynamics. Agroecological pest management in an increasingly variable and extreme climate will likely benefit from the development of strategies that account for the seasonal timing of potential heat events and from the continued use of crop varieties bred for pest resistance, which our results suggest may dampen the impacts of extreme temperatures on crop‐pest interactions.

Simulation of electrostatic particulate matter sensor regeneration based on the particulate deposition patterns

PurposeThis study aims to establish a multi-physics-coupled model for an electrostatic particulate matter (PM) sensor. The focus lies on investigating the deposition patterns of particles within the sensor and the variation in the regeneration temperature field.Design/methodology/approachComputational simulations were initially conducted to analyse the distribution of particles under different temperature and airflow conditions. The study investigates how particles deposit within the sensor and explores methods to expedite the combustion of deposited particles for subsequent measurements.FindingsThe results indicate that a significant portion of the particles, approximately 61.8% of the total deposited particles, accumulates on the inside of the protective cover. To facilitate rapid combustion of these deposited particles, a ceramic heater was embedded within the metal shielding layer and tightly integrated with the high-voltage electrode. Silicon nitride ceramic, selected for its high strength, elevated temperature stability and excellent thermal conductivity, enables a relatively fast heating rate, ensuring a uniform temperature field distribution. Applying 27 W power to the silicon nitride heater rapidly raises the gas flow region's temperature within the sensor head to achieve a high-temperature regeneration state. Computational results demonstrate that within 200 s of heater operation, the sensor's internal temperature can exceed 600 °C, effectively ensuring thorough combustion of the deposited particles.Originality/valueThis study presents a novel approach to address the challenges associated with particle deposition in electrostatic PM sensors. By integrating a ceramic heater with specific material properties, the study proposes an effective method to expedite particle combustion for enhanced sensor performance.

Waste Identification In The Production Process PTC Ceramic Heating Element With Lean Manufacturing Approach At CV. Sulis Keramik

A firm called CV. Sulis Keramik makes parts for mosquito mats; these parts come in the shape of PTC heating elements. A kind of positive temperature coefficient thermistor used in heating applications is the ptc heating element. There are still many different waste indicators throughout the production process, which lowers the process's efficacy and efficiency. Defects with a 10% defect rate are among the main issues. Furthermore, there exist other indicators of waste associated with waiting times, transportation, and other wastes. With the use of lean manufacturing techniques, this project seeks to eradicate waste from CV Sulis Keramik ptc heating element production process. Value stream mapping in its current state, waste assessment models, value stream analysis tools, production system improvement, and designing future value stream mapping were all shown in the research's first stage.

Effect of Ceramic Veneering on the Microstructure of Pre-sintered Cobalt-Chromium, Compared to Pre-sintered Zirconia and Conventional Cast Alloys.

Objectives: We aimed to evaluate ceramic-alloy interface and emphasize the alteration of alloy microstructure after ceramic layering. Materials and Methods: Thirty-two discs made from a ceramic-alloy combination of pre-sintered cobalt-chromium (CoCr), cast CoCr, cast nickel-chromium (NiCr), or pre-sintered zirconia were prepared with eight discs in each group. Four specimens were examined as manufactured and four were ceramic-layered. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-Ray diffractometer (XRD), and an atomic force microscope were used for analysis. Non-layered specimens received ceramic fire-heating without adding any ceramic. Alloy microstructure was compared before and after ceramic veneering or heating within the same group. Mean differences in grain size and surface roughness were compared among groups. P<0.05 was considered significant. Results: SEM showed a close bonding interface between alloys and ceramics. EDX demonstrated differences compared to the manufacturer's composition. Ceramic-layering reduced grain size for both milled alloys (P<0.05), whereas grain size increased in cast groups (P=0.011). Heat treatment did the same for the CoCr groups (P=0.013). Ceramic veneering increased the surface roughness of the cast CoCr (Gi) (P=0.029) and NiCr (Wi) (P=0.005) groups, whereas zirconia roughness average (Ra) showed a slight decrease (P=0.282). XRD showed no differences among zirconia, NiCr, and milled CoCr groups before and after veneering. Crystallite size differed between monoclinic and tetragonal phases in zirconia. Conclusion: The study highlights that ceramic-layering induces significant microstructural changes in alloys, enhancing bonding potential and mechanical stability. Pre-sintered materials show a fine homogeneous surface, optimizing ceramic adherence and potentially improving clinical outcomes.

Preparation and characterization of Al-12Si/ceramic composite phase change heat storage material

Preparation and characterization of Al-12Si/ceramic composite phase change heat storage material

Pyramid Textured Photonic Films with High-Refractive Index Fillers for Efficient Radiative Cooling.

Sub-ambient cooling technologies relying on passive radiation have garnered escalating research attention owing to the challenges posed by global warming and substantial energy consumption inherent in active cooling systems. However, achieving highly efficient radiative cooling devices capable of effective heat dissipation remains a challenge. Herein, by synergic optimization of the micro-pyramid surface structures and 2D hexagonal boron nitride nanoplates (h-BNNs) scattering fillers, pyramid textured photonic films with remarkable solar reflectivity of 98.5% and a mid-infrared (MIR) emittance of 97.2% are presented. The h-BNNs scattering filler with high thermal conductivity contributed to the enhanced through-plane thermal conductivity up to 0.496W m-1 K-1 and the in-plane thermal conductivity of 3.175W m-1 K-1. The photonic films exhibit an optimized effective radiative cooling power of 201.2W m-2 at 40°C under a solar irradiance of 900W m-2 and a daily sub-ambient cooling effect up to 11°C. Even with simultaneous internal heat generation by a 10W ceramic heater and external solar irradiance of 500W m-2, a sub-ambient cooling of 5°C can be realized. The synergic matching strategy of high thermal conductivity scattering fillers and microstructured photonic surfaces holds promise for scalablesub-ambient radiative cooling technologies.

Flow Rate Sensor inside Infusion Tube

Infusion systems are widely used in clinical medicine. Intravenous infusion therapy must be monitored to ensure patient safety. We proposed a compact flow rate sensor device based on the time-of-flight method. This device included one ceramic heater and two infrared sensors. Practical sensor prototypes were fabricated and characterized. The response time was 30 s. The sensor range was estimated to be 33 dB from μL/min to tens of mL/min, covering almost the entire usage range This flow rate sensor can be applied to common infusion tubes. Through the use of a mobile phone app, detailed information can be presented in real time.

Material selection and manufacturing for high‐temperature heat exchangers: Review of state‐of‐the‐art development, opportunities, and challenges

AbstractMany energy systems demand heat transfer at high temperatures to keep up with high demand for power, so high‐temperature material that can perform and last under these harsh conditions is needed for heat exchangers. The engineering requirements for these high‐temperature heat exchanger material call for high thermal conductivity, high resistance to fracture, high resistance to creep deformation, environmental stability in environments associated with the application, and high modulus of elasticity while maintaining low cost to make and maintain. Naturally, ceramics are a good solution for this endeavor. In the past, high‐temperature heat exchangers made from ceramics have been used. We provide examples of ceramics in relevant heat exchange applications and provide motivation where additive manufacturing (AM) can improve efficiency. AM for the relevant material is under development, and we provide insight on the AM of ceramic materials and examples of AM heat exchangers keeping cost in mind. The motivation of the review paper is to provide a framework for material and manufacturing selection for high‐temperature heat exchangers for AM to keep up with the demand for better efficiency, better material, better manufacturing, and cost moving forward with AM technology in high‐temperature ceramic heat exchangers.

Estimating incident infrared radiation intensity on a horizontal surface

The study aims to characterize external IR heating sources, operating in free convection atmosphere, qualitatively and quantitatively for various applications. It employs non-invasive IR thermography to measure steady-state irradiations from a ceramic IR heater at variable voltages (60–150 V) using the surface energy budget (SEB) method which relies on only two measured parameters (surface and ambient temperature). The free convection heat transfer from the plate is demarcated between the thermal boundary layer (TBL) and buoyant plume-dominated region by temperature histogram tool. Nearly 78 ± 5 % of the plate area is occupied by the hot plume(s) in the studied voltage range. Estimated irradiation agrees fairly well with one another (within ± 10 %). Additionally, the time response of the plate was measured to be ∼ 120 s. This fast response can be made even faster, by reducing the thermal mass, eventually leading to low-cost IR sensors.

S-shaped tellurite optical fiber surface plasmon resonance sensor for temperature and refractive index measurement

In this paper, an all-fiber S-shaped structure optical fiber surface plasmon resonance (SPR) sensor is proposed for temperature and refractive index measurement. The sensor is made of a single-mode tellurite optical fiber (TOF), and the middle part of the single-mode TOF is heated by a ceramic heating rod to form an S-shaped sensing region, and a 50 nm gold film is deposited in the S-shape sensing area to excite SPR. Based on the excellent properties of tellurite optical fiber, the prepared optical fiber sensor can be used for high sensitivity temperature and refractive index detection. The highest refractive index sensitivity is up to 1068.59 nm/RIU in the range of 1.333–1.380, and the temperature sensitivity is up to −0.713 nm/°C in the range of 30–150 °C. The proposed sensor is simple to fabricate, low-cost, and compact, and can be widely used in biochemical analysis, complex environmental temperature monitoring and other fields.

Joule heat mediated by graphite felt enhances peroxymonosulfate activation and carbamazepine degradation: Efficiency and mechanism

Thermal activation of persulfate (PS) is a simple and effective method to generate sulfate radicals (SO4̇‾) for pollutant degradation but its practical application was severely restricted by the excessive energy consumption. In this study, a low energy consumption but efficient Joule heat-activation strategy was developed. The temperature of the reaction solution (TRS) rose to 76.9 °C within 30 min after 5 V external voltage (Uex) was applied onto the two sides of a graphite felt (GF) with the thickness of 6 mm (GF-6). Correspondingly, the peroxymonosulfate (PMS) decomposition ratio and the degradation efficiency of carbamazepine (CBZ) reached 82.6 % and 97.5 %. The catalytic activation of PMS on the surface of GF was the dominant pathway to generate free radicals during the Joule heating process rather than the heat-activation pathway. More importantly, removing per milligram of CBZ only consumed 5.6 kJ electric energy which was significantly lower than that of the common heating methods (namely, 80 °C water bath heating and electrical heating at 5 V using a commercially available ceramic electric heating rod). Impressively, this Joule heating system exhibited wide applicability and prominent reusability. Overall, this work developed an effective PMS thermal activation strategy with low power consumption using the widely available GF and realized efficient degradation of typical organic pollutants.

Experimental and Numerical Investigation of Single-Phase Liquid Cooling for Heterogeneous Integration Multichip Module

Abstract The variety of new electronic packaging technologies has grown significantly over the last 20 years as a result of market demands for higher device performance at lower costs and in less space. Those demands have pushed for heterogeneous packaging, where computer chips with different stack heights are closely packed, creating nonuniform heat flux and temperature and additional challenges for thermal management. Without implementing an appropriate thermal management strategy for heterogeneous packages, large temperature gradients can be observed within the package, which would increase the thermal stresses on the chip and raise reliability issues. To mimic this real-life scenario of such packaging, an experimental setup was designed and built. The design of the new experimental setup consists of four identical 1.2 cm × 1.2 cm ceramic heaters, each of which is connected to a separate power supply and can reach a heat flux of 140 W/cm2. Accordingly, this mock package is capable of delivering different power levels to mimic different multicore microprocessor conditions. To give the heater the ability to move precisely in the x-, y-, and z-directions, each heater is mounted to an XYZ linear stage. Deionized water (DI) was used as the working fluid, and a pin-fin heat sink was used to run the initial steady-state tests on the experimental rig. The tests showed how different flow rates at a constant fluid temperature and input power affect the temperatures of the heaters and the thermohydraulic performance of the heat sink. In addition, a three-dimensional numerical model has been developed and validated with experimental data in terms of heat sink pressure drop and the temperatures of the heaters.

Modeling of Additively Manufactured Ceramic Heat Exchangers with Semi-Elliptical Cross-Section Flow Channels

An approximate and easily applied analytical model was developed for heat transfer calculations of heat exchangers consisting of multiple rows and columns of heat transfer fluid flow channels with semi-elliptical cross sections. Heat exchangers of this type are being developed by using ceramic material and additive manufacturing for high temperature and pressure-concentrating solar electric power plants. Calculations using the model require only the geometrical dimensions and flow conditions of the heat exchanger. Comparisons of modeling predictions, with both simulation results and experimental data, were conducted to verify the viability of the model. The results showed good agreement where almost all the modeling predictions were within 20% of the simulation results or the experimental data. The proposed modeling approach is more generally applicable to heat transfer analysis of heat exchangers with similar flow channel configurations to those considered in this study.

Room–temperature hydrogen sensitive Pt–SnO2 composite nanoceramics: Dormancy and a practicable regeneration method

Dormancy has been suggested to be used for metal oxide gas sensors to specifically refer to their response decrease or disappearance after long periods of inactivity at room temperature. In this paper, 1 wt% Pt–SnO2 composite nanoceramics with especially strong responses to hydrogen–containing atmospheres at room temperature, e.g. a response of 11170 to 1 % H2–20 % O2–N2, were successfully prepared through pressing and sintering. A clear dormancy has been observed for them as their responses decreased seriously with time when they were stored in ambient air at room temperature. Commercial ceramic heating plates (Metal Ceramics Heater, MCH) of 10 mm × 10 mm were attached to bars of 1 wt% Pt–SnO2 composite nanoceramics. Dormant bars after 12 months of storage were completely regenerated through a heat–treatment of 200 °C for 10 min by attached MCH ceramic heating plates. According to X-ray photoelectron spectroscopy analyses, the formation of hydroxyl groups on SnO2 in Pt–SnO2 composite nanoceramics and deposition of impurity gases like H2S were proposed responsible for the dormancy, and their removal through mild heat–treatments result in the regeneration. It is suggested that heaters like commercial MCH ceramic heating plates should be included in future room–temperature gas sensors to provide a practicable regeneration from dormancy when needed.

Fabrication of High Thermal Conductivity Aluminum Nitride Ceramics via Digital Light Processing 3D Printing.

The sintering of high-performance ceramics with complex shapes at low temperatures has a significant impact on the future application of ceramics. A joint process of digital light processing (DLP) 3D printing technology and a nitrogen-gas pressure-assisted sintering method were proposed to fabricate AlN ceramics in the present work. Printing parameters, including exposure energy and time, were optimized for the shaping of green bodies. The effects of sintering temperature, as well as nitrogen pressure, on the microstructure, density, and thermal conductivity of AlN ceramics were systematically discussed. A high thermal conductivity of 168 W·m-1·K-1 was achieved by sintering and holding at a significantly reduced temperature of 1720 °C with the assistance of a 0.6 MPa nitrogen-gas pressure. Further, a large-sized AlN ceramic plate and a heat sink with an internal mini-channel structure were designed and successfully fabricated by using the optimized printing and sintering parameters proposed in this study. The heat transfer performance of the ceramic heat sink was evaluated by infrared thermal imaging, showing excellent cooling abilities, which provides new opportunities for the development of ceramic heat dissipation modules with complex geometries and superior thermal management properties.