Isothermal Tests Research Articles

Equilibrium Isotherm and Kinetic Modeling for Lead (II) Adsorption on The Modified Rice Husk as Sustainable Applications to Produce Activated Carbon Alternatives

The aim of the study is the assessment the performance of the suggested adsorbent. After testing a number of pH values to achieve this objective, it was found that the best lead ion removal efficiency occurred during batch studies at pH 5. According to studies on how agitation speed affects batch adsorption, 180 rpm is the appropriate shaking speed. The optimal contact time for the operation was 180 minutes. Furthermore, as the contact time rose, the adsorption effectiveness improved. The effectiveness of the rice husk’s absorptive ability and elimination of Lead (Pb) from aqueous solutions was evaluated. The findings revealed that Pb has 92% elimination efficiency. The greatest capacity of Pb adsorption of the suggested adsorbent in a batch system was 6.93 mg/g. Three models have fitted to a number of equilibrium isothermal tests: Langmuir, Freundlich, and Temkin. With a correlation coefficient of R2 0.98, the Freundlich isotherm model offered the greatest match-up with the experiments for this system. The rice husk equilibrium isotherms were of a favorable type. The kinetics of lead ions adsorption onto rice husk appears to be best described by the intra-particle diffusion model. According to the correlation coefficient (R 2) comparison values of each curve for the four models where were the values (Intra-particle diffusion > Pseudo-Second Order > Pseudo-First Order > Elovich). The findings suggest that rice husk is a potential material for eliminating impurities and pollutants from wastewater. It is a powerful adsorbent that is capable of efficiently removing a number of heavy metal contaminants from wastewater.

Research on the Optimization for Acidification Modification Scheme Considering Coal's Wettability Based on the AHP-TOPSIS Method.

Acidification technology is an important measure for enhancing the extraction of coalbed methane from seams with low permeability and abundant minerals, and the acidification scheme is the key to the success of acidification treatment. To determine the optimal acidification modification scheme, an improved AHP-TOPSIS method is proposed to decide on the optimal conditions for wettability modification. This method constructs an evaluation index system, taking the wettability of coal as the target layer and the pro/hydrophobic functional groups in coal as the index layer. Meanwhile, it innovatively takes the adsorption energy of each functional group when absorbing a single water molecule as the basis for assigning weights to the evaluation indexes. Then, nine acidification modification schemes are evaluated and selected by the improved AHP-TOPSIS method based on the test results of different schemes to get the optimal one. The optimal scheme selected by the AHP-TOPSIS method is validated by water adsorption tests and isothermal adsorption tests. The results showed that the significance of each evaluation index is ranked as follows: aromatic structures > hydroxyl groups > aliphatic functional groups > oxygen-containing functional groups. The optimal acidification modification scheme is selected by the AHP-TOPSIS method with a HF concentration of 4% and a reaction time of 6 h. The ranking of acidification modification schemes obtained by the AHP-TOPSIS method is in high agreement with the ranking of water adsorption tests. When compared with raw coal, the coal samples treated with the optimal scheme have lower adsorption capacity for gas, which indicates that the aforementioned method could be used to evaluate and select the optimal acidification modification scheme, and the selected optimal scheme has the potential to increase the output of coalbed methane.

Toward Continuous Molecular Testing Using Gold-Coated Threads as Multi-Target Electrochemical Biosensors.

Analytical systems based on isothermal nucleic acid amplification tests (NAATs) paired with electroanalytical detection enable cost-effective, sensitive, and specific digital pathogen detection for various in situ applications such as point-of-care medical diagnostics, food safety monitoring, and environmental surveillance. Self-assembled monolayers (SAMs) on gold surfaces are reliable platforms for electroanalytical DNA biosensors. However, the lack of automation and scalability often limits traditional chip-based systems. To address these challenges, we propose a continuous thread-based device that enables multiple electrochemical readings on a functionalized working electrode Au thread with a single connection point. We demonstrate the possibility of rolling the thread on a spool, which enables easy manipulation in a roll-to-roll architecture for high-throughput applications. As a proof of concept, we have demonstrated the detection of recombinase polymerase amplification (RPA) isothermally amplified DNA from the two toxic microalgae species Ostreopsis cf. ovata and Ostreopsis cf. siamensis by performing a sandwich hybridization assay (SHA) with electrochemical readout.

Modular DNAzymes-Hydrogel Membrane Carriers for Highly Sensitive Isothermal Cross-Cascade Detection of Pathogenic Bacteria Nucleic Acids.

The increasing prevalence of antimicrobial resistance has called for improved diagnostic testing of pathogenic bacteria. However, the development of rapid, cost-effective, and easy-to-use tests for bacterial infections remains a constant challenge. Here, we report a class of modular hydrogel membrane carriers incorporated with composite DNAzymes, which enable rapid and highly sensitive detection of pathogenic bacteria gene target analytes. We apply free radical polymerization to incorporate composite DNAzymes, consisting of an RNA substrate component and a DNAzyme component (e.g., 10-23 or 8-17 DNAzymes), into polyethylene glycol diacrylate polymer networks. Initiated by a nucleic acid target acting as an assembly facilitator, multicomponent DNAzymes are combined to cleave the RNA substrate component in the hydrogel carriers, which releases the DNAzyme component to cleave RNA reporter probes to generate fluorescence. We modulate the morphology, composition, and microporous structures of the DNAzyme carriers to achieve quantitative assay performance. We demonstrate a rapid and high-sensitivity detection of C. trachomatis gene target analytes as low as 50 fM in a short assay time of 25 min. The work represents a crucial step forward in the development of a generic, isothermal, and protein enzyme-free pathogenic bacteria testing platform technology.

Energy Variation Features during the Isothermal Adsorption of Coal under High-Temperature and High-Pressure Conditions

This paper aims to describe methane adsorption in coal under the conditions of high temperature and high pressure, as well as quantitatively decipher the change rule of energy in the isothermal adsorption process. The isothermal adsorption test was carried out with four groups of middle-rank coals from the Linxing area with different degrees of metamorphism. The impacts of the degree of deterioration of coal, temperature, and pressure on adsorption were analyzed with regard to the adsorption amount, adsorption potential, and adsorption space. Additionally, the energy change during the adsorption of methane by the coal was considered. The results show that the coal adsorption capacity hinges on the degree of deterioration of the coal, as well as the pressure and temperature. Additionally, the impact of temperature upon coal methane adsorption under depth conditions is highlighted. Like the adsorption space, the adsorption potential is an important parameter used to quantitatively characterize the adsorption ease and adsorption capacity; furthermore, the adsorption potential of millipores exceeds that of mesopores, as they are capable of offering a larger specific surface area for adsorption. The total decrease in the surface free energy during adsorption increases as the pressure increases; simultaneously, the increase rate is fast and then slow. The total decrease in the above-described free energy diminishes as the temperature escalates. Under the same pressure, the total decrease in the aforementioned free energy increases as the reflectance of the specular body of the coal increases. The decrease in the aforementioned free energy at each point of pressure lessens as the pressure grows; notably, when the pressure is comparatively low, the reduction is very fast. As the pressure escalates continuously, the decrease speed is slow. Regarding the effect of pressure and temperature upon adsorption, the adsorption gas volume of coal exists in a conversion depth from 1200 m to 1500 m; at the same time, the impact of pressure upon adsorption is dominant up to this depth. Additionally, beyond this depth, temperature gradually comes to have the greatest impact on adsorption.

A new cellular automata model for hot deformation behavior of AZ80A magnesium alloy considering topological technique

In this paper, the CA model of grain topological deformation technique (T-CA) and the physical constitutive model considering strain are introduced to study the hot deformation behavior of extruded AZ80A magnesium alloy. The isothermal compression test of extruded AZ80A magnesium alloy was carried out on the Gleeble-3800 thermal simulator. The deformation temperature and strain rate were 598 K∼723 K and 0.001 s−1∼1 s−1, respectively. According to the experimental results, a phenomenological constitutive model of flow stress considering strain was constructed. The reliability of the model was verified by comparing the experimental and predicted flow stress. The influence of thermal deformation parameters, i.e., deformation temperature, strain rate, and strain, on the DRX kinetic curve and grain size evolution was studied based on the CA model with the introduction of grain topological (T-CA) deformation technology. Meanwhile, the influence of initial grain size on dynamic recrystallization was studied using the conventional CA model (C-CA) and the CA model with topological deformation (T-CA) technology. Finally, the accuracy of the T-CA model was verified by combining physical experiments and electron backscatter diffraction (EBSD) technology. At the temperature of 598 K, the strain rate of 0.1 s−1, and the strain of 0.91, the error between the average grain size simulated by the topological CA (T-CA) model and the experimental results is 7.6 %, which is consistent with the experimental results. When the initial grain size is 43 µm, compared with the conventional CA simulation method (C-CA), the CA simulation method with the introduction of grain topological deformation can promote the occurrence of recrystallization, improving the simulation speed and accuracy. The error between the percentage of recrystallization and the experiment is 4.5 % and 3.2 %, respectively, indicating that the simulation method with the introduction of grain topological deformation (T-CA) can accurately predict the dynamic recrystallization behavior of AZ80A magnesium alloy.

Early metakaolin reactions in pozzolanic R3-test: calorimetry baseline correction of initial temperature jump due to ex-situ mixing

The increasing concerns regarding global warming and the scarcity of raw materials in the construction industry have led to a growing need for alternative low-carbon binders to partially replace ordinary Portland cement. To assess the suitability of pozzolans as supplementary cementitious materials (SCMs), the R3-test has been introduced and successfully validated for a wide range of materials. This test provides an opportunity to analyze the reactivity classification and study the reaction mechanisms and kinetics of novel SCMs in a well-controlled environment. In this study, the focus lies on evaluating the early reactions of lime paste samples through isothermal calorimetry tests conducted at 40 °C. However, conventional mixing methods present experimental challenges. In-situ mixing fails to achieve proper paste homogenization, while ex-situ mixing results in a temperature difference at the start of testing due to the elevated testing condition of 40 °C. To address these concerns, a novel calorimetric methodology is proposed for early detection of reactivity responses. The main concept involves establishing a baseline correction for the temperature difference caused by ex-situ mixing, which is calibrated using an inert sample. This correction allows for the extraction of the heat generated by the early reactions. Combined with the Tian time correction, this methodology enables the evaluation of early reactions in lime paste samples measured with isothermal calorimetry at 40 °C within the first 100 min after mixing. The effectiveness of this methodology was demonstrated by evaluating the early reactions and the impact of potassium sulfate on three different types of metakaolin.

Polysaccharides-based adsorbents for removal of Congo red dyes from wastewater

Gums Arabic (GA) and Xanthan (GX) are natural polysaccharides that can be extracted by natural means for applications, such adsorption of pollutants. Structural modifications such as carboxymethylation on bio-adsorbent materials, can be performed to improve its adsorptive properties. Development of polymeric nanoparticles is an economical and favorable option for the adsorption of Congo red dye, which has high toxicity and is resistant to traditional removal processes. In this work, it was developed nanoparticles (NPs) of natural GA (NPGA) and GX (NPGX) and their carboxymethylated forms (NPCMGA and NPCMGX) aiming to evaluate the adsorption of Congo red (CR) dye. NPs are sized from 133 to 1099 nm at an average zeta potential of -13 mV, suggesting stability to absorb dyes. NPGX and NPCMGX absorbed a substantially higher amount of dye than the other NPs. The kinetic studies showed that adsorption process follow pseudo-second order model, suggesting that chemisorption control the process, and the isotherm test revealed that samples fit Langmuir model, with a homogeneous adsorption profile for the two carboxymethylated samples with a maximum adsorption capacity of 182,82 mg/g for NPCMGX and 757,58 mg/g for NPGX. These findings indicate that NPs from Xanthan Gum can be used for removal CR in contaminated water and wastewater.

Characterization and constitutive analysis-based crystal plasticity of warm flow and fracture behaviours of 2060 Al–Cu–Li alloy

AA2060-T8 is a relatively new Al–Cu–Li alloy developed in the last few years as a lightweight alternative to conventional Al alloys. Thus, it is essential to characterize the warm flow, fracture, and anisotropic behaviours of this alloy and propose constitutive analysis-based crystal plasticity (CP) modelling to link its mechanical behaviour with the microstructural state. Therefore, in this study, isothermal warm tensile tests were conducted using a Gleeble-3800 thermomechanical simulator and different sample orientations at temperatures and strain rates varying from 373 to 573 K and 0.001–0.1 s−1, respectively. The tensile behaviour of the 2060 Al–Cu–Li alloy sheet depends on the sample orientations, which results in significant anisotropy. The anisotropic degree of the tensile properties of this alloy was significantly reduced by increasing the forming temperature above 473 K. In addition, the fracture behaviours of 2060 Al–Cu–Li sheets were transformed from mixed ductile-brittle fracture mode to ductile fracture mode by decreasing strain rates and increasing the temperatures, respectively. Afterward, a novel crystal plasticity model was proposed to describe the grain behaviour and the deformation mechanism of 2060 Al–Cu–Li alloy under warm forming conditions. The developed constitutive model was implemented using the monolithic time-integration algorithm-based backward Euler method. The results acquired from the proposed constitutive analysis agree well with those obtained from experimentation in all testing conditions. This indicates its ability to accurately predict the warm flow behaviour of 2060 Al–Cu–Li alloy under different strain rates and loading directions.

Quantitative characterization of the interfacial transition zone around lightweight and normal aggregates in cement mortars at different water-to-binder ratios

The interfacial transition zone (ITZ) between aggregates and cement binders has long been known as the most vulnerable to crack resistance among the three phases in heterogeneous concretes [i.e., aggregate, ITZ, cement binders] owing to its porous microstructure. The characteristics of the ITZ are determined by the aggregate types, water-to-binder (W/B) ratios, and supplementary cementitious materials. Furthermore, the correlations between the physicochemical properties of the interface in the vicinity of saturated lightweight aggregates (LWAs) and the mechanical properties of cement concretes are still controversial because of the rough surface and ambiguous water desorption behavior of LWAs. To clarify such correlations, in this study we systemically investigated the effect of different water desorption behaviors of LWAs in cement mortars for various W/B ratios ranging from 0.2 to 0.5 on the mechanical properties of cement mortars via isothermal calorimetry tests, scanning electron microscopy, and nanoindentation grid tests. In addition, the experimental results were compared to those of mortars containing fine normal-weight aggregates (NWAs). These investigations clarified the effect of mechanical properties and porosity of the ITZ on the inherent strength of cement mortars with different aggregate types and W/B ratios. An improvement in the ITZ morphology around the LWAs was observed in relation to that around the NWAs for W/B > 0.3. Conversely, the porosity increased significantly on the LWA surface with respect to that on the NWA surface for W/B = 0.2. Nanoindentation tests revealed the deterioration of the elastic moduli and hardness of mortars containing LWAs at all investigated W/B ratios.

Can Martensitic Phase Transformation Measured by Magnetic Methods be an Indicator of Fatigue Damage in Austenitic Steel at Elevated Temperature and Thermo-Mechanical Loading?

The phenomenon of phase transformation from paramagnetic γ austenite to ferromagnetic α' martensite in metastable austenitic stainless steels under fatigue loading is well investigated, especially at ambient temperature. Generally, it can be said that at ambient temperature, the amount of martensite is proportional to the accumulated plastic strain and, therefore, can be an early indicator of fatigue damage. The problem arises at elevated temperatures when the thermal energy can severely or even completely inhibit the phase transformation. In this case, the amount of α'-martensite can no longer be a good indicator of fatigue damage. The question is, where is the limit the deformation-induced martensite can still be used as a fatigue damage indicator? To answer this question, several fatigue tests have been performed on AISI 347 (X6CrNiNb18-10), a metastable austenitic stainless steel often used in the piping of European nuclear powerplants. Tests included isothermal fatigue tests as well as thermo-mechanical fatigue (TMF) loading in the range of 25 to 320 °C. Deformation-induced martensite was measured in situ by means of a uniaxial magnetic balance, from which the rate of phase transformation was obtained. Fatigue specimens were then cut to investigate the distribution of martensite in the gauge length by means of magnetic force imaging. The results showed that isothermal fatigue loading results in a steady decrease in phase transformation rate with temperature. Initial martensite nucleation was observed to be different at elevated temperatures and occurred only at the surface, where sufficient shear deformation was present. TMF tests showed higher than isothermal rates of phase transformation. Peak temperatures above 300 °C were nevertheless enough to severely reduce the formation of α' martensite, even when cooled back to ambient temperature in the other half of the TMF cycle.

A Study on Long-Term Oxidation and Thermal Shock Performance of Nanostructured YSZ/NiCrAlY TBC with a Less Dense Bond Coat.

This paper focused on studying the performance of a nanostructured thermal barrier coating (TBC) system deposited by APS, which had a bond coat with inter-lamellar porosities that resulted during the manufacturing process. The higher porosity level of the bond coat was studied as a possible way to keep the thickness of the TGO under control, as it is distributed on a higher surface, thereby reducing the chance of top-coat (TC) spallation during long-term oxidation and high-temperature thermal shock. The TBC system consisted of nanostructured yttria partially stabilized zirconia (YSZ) as a top coat and a conventional NiCrAlY bond coat. Inter-lamellar porosities ensured the development of a TGO distributed on a higher surface without affecting the overall coating performance. Based on long-term isothermal oxidation tests performed at 1150 °C, the inter-lamellar pores do not affect the high resistance of nanostructured TBCs in case of long-term iso-thermal oxidation at 1150 °C. The ceramic layer withstands the high-temperature exposure for 800 h of maintaining without showing major exfoliation. Fine cracks were discovered in the ceramic coating after 400 h of isothermal oxidation, and larger cracks were found after 800 h of exposure. An increase in both ceramic and bond-coat compaction was observed after prolonged high-temperature exposure, and this was sustained by the higher adhesion strength. Moreover, in extreme conditions, under high-temperature thermal shock cycles, the TBC withstands for 1242 cycles at 1200 °C and 555 cycles at 1250 °C.

Construction of Process Map and microstructure evolution of 5 vol.% (TiB + Y2O3)/α-Ti composites under isothermal compression

This study conducted isothermal compression tests on as-cast 5 vol% (TiB + Y2O3)/α-Ti composites at various deformation temperatures ranging from 950–1150 °C and strain rates of 10−3∼1.0 s−1. The corresponding thermal deformation activation energy and the constitutive equations were derived from the stress-strain curves of the different phase regions. Then the Process Map of the composites was constructed and the regions of prone plastic processing were obtained as 950–1020 °C, 0.003–0.1 s−1 and 1090–1140 °C, 0.01–0.2 s−1, and the instability zones were 0.3–1 s−1, 950–970 °C, 0.3–1 s−1 and 1010–1070 °C. After analyzing the thermal deformation behavior of the composites, the microstructure evolution was also investigated. The softening mechanism in (α + β) phase region is mainly DRV and DRX of α phase, while in β phase region is mainly DRX of β phase. The reinforcement can impede dislocation movement, thus promoting DRX of the matrix and impeding subsequent grain growth.

The role of (Fe,Al)2Nb Laves phase on the high temperature oxidation behaviour of intermetallic Fe–26Al–4Nb iron aluminide

The role of the (Fe,Al)2Nb Laves phase on the high temperature oxidation mechanisms of Fe–26Al–4Nb (at%) was investigated between 700 °C and 1000 °C in air for 500 h. The (Fe,Al)2Nb Laves phase that was already present in as-cast state was selectively oxidised at all temperatures but showed the formation of different oxides including Fe2O3, AlNbO4, and Al-rich oxide depending on test temperature. Unharmed (Fe,Al)2Nb was newly formed below the oxide scale at 700 °C and 800 °C, while at 900 °C and 1000 °C no unharmed Laves phase below the oxide layer was observed. The discontinuous isothermal testing showed a change of kinetics at 700 °C and 800 °C after 10 h of oxidation. At 1000 °C, the (Fe,Al)2Nb Laves phase was additionally identified to initiate oxide spallation.

Formation and evolution behavior of M6C carbide in a Ni-W-Cr superalloy

The carbide formation and evolution of a new Ni-26W-6Cr (wt.%) superalloy for the 800 °C molten salt reactor (MSR) was investigated by homogenization heat treatment tests and the effect of carbide characteristics on the plastic deformation behavior was further investigated by isothermal simulated tensile tests. The plastic deformation properties of Ni-26W-6Cr superalloys are associated with the morphological characteristics and distribution of carbides. During homogenization at 1220 °C, a unique phenomenon was discovered, that is, the precipitation of the acicular carbide. The XRD, TEM and EBSD results show that this acicular carbide is distributed along the particular crystal plane of the γ matrix. Based on crystallographic theory, there is no obvious orientation relationship between the carbide and the γ matrix, which is prone to cracking along the carbide/γ interface during deformation. After homogenization at 1220 °C for 48 h, the acicular M6C carbides dissolved and the discrete granular M6C carbides distributed diffusely at the grain boundaries can relieve stress concentration and strengthen the grain boundaries, reducing the deformation resistance of the alloy, effectively inhibiting grain boundary slip and thus inhibiting crack propagation, and improving the tensile strength and plasticity of the material.

Effect of hydrogen on hot deformation behavior and microstructure evolution of Ti65 alloy

Thermohydrogen processing (THP) is a potential method for enhancing the formability of titanium alloys. However, there has been no report on the deformation behavior and microstructure evolution of hydrogenated Ti65 alloys, which are new high-temperature titanium alloys used above 600 °C. In this study, we conducted a series of isothermal hot compression tests in the α+β and β phase field of Ti65 alloy specimens with varying hydrogen content to investigate the effect of hydrogen on high-temperature flow behavior and microstructure evolution. The results showed that after hydrogenation, the number of α phases in Ti65 alloy significantly decreased. δ hydride precipitates were observed in the specimen with 0.43 wt% hydrogen, resulting in an apparent refinement of its microstructure. Adding 0.25 wt% hydrogen reduced the deformation temperature by about 60 °C and increased deformation strain rate by nearly two orders of magnitude for Ti65 alloy. This improvement can be attributed to how hydrogen promotes dislocation movement, dynamic recrystallization (DRX), and dynamic recovery (DRV) during deformation. Similarly, as strain increases, the instability region on the hot processing map gradually decreases or even disappears due to broadening effects from added hydrogen; thus expanding its hot processing window further. This research deepens our understanding regarding deformation behavior while providing theoretical guidance for THP applications using Ti65 alloy.

Accelerated coarsening behavior of the γ´-phase in CMSX-4 during non-isothermal heat treatment

In literature, microstructural investigations can be found comparing the evolution of the well-known γ/γ ´ -phase morphology of nickel-based superalloys for long-term heat treatments with and without mechanical load, as well as for isothermal and non-isothermal creep tests. However, data of experiments conducted under non-isothermal conditions without an applied load are hard to find. To close this gap, isothermal and non-isothermal heat treatments without a mechanical load were conducted. Conductive heating was applied to samples that consisted of segments with different cross sections and allowed the simultaneous testing at different temperatures. The microstructural changes were examined by scanning electron microscopy after 500 h and 1000 h. Several established methods for the quantification of the γ ´ -phase coarsening were evaluated and employed for comparison of the two heating conditions studied. The coarsening was more distinct in samples heat-treated under non-isothermal conditions at all temperatures investigated. This was also verified by calculating the connectivity number NA, which was found to be the most useful parameter for quantification of microstructural changes observed. The γ ´ -precipitates became more connected during the heat-treatment, but no preferred direction of coarsening was observed like during rafting under an applied load. Therefore a more general particle agglomeration mechanism is assumed to be responsible for coarsening of the γ ´ -phase.

In-situ isothermal aging TEM analysis of a micro Cu/ENIG/Sn solder joint for flexible interconnects

Sn/ENIG has recently been used in flexible interconnects to form a more stable micron-sized metallurgical joint, due to high power capability which causes solder joints to heat up to 200 °C. However, Cu6Sn5 which is critical for a microelectronic interconnection, will go through a phase transition at temperatures between 186 and 189 °C. This research conducted an in-situ TEM study of a micro Cu/ENIG/Sn solder joint under isothermal aging test and proposed a model to illustrate the mechanism of the microstructural evolution. The results showed that part of the Sn solder reacted with Cu diffused from the electrode to form η´-Cu6Sn5 during the ultrasonic bonding process, while the rest of Sn was left and enriched in a region in the solder joint. But the enriched Sn quickly diffused to both sides when the temperature reached 100 °C, reacting with the ENIG coating and Cu to form (NixCu1-x)3Sn4, AuSn4, and Cu6Sn5 IMCs. After entering the heat preservation process, the diffusion of Cu from the electrode to the joint became more intense, resulting in the formation of Cu3Sn. The scallop-type Cu6Sn5 and the seahorse-type Cu3Sn constituted a typical two-layered structure in the solder joint. Most importantly, the transition between η and η’ was captured near the phase transition temperature for Cu6Sn5 during both the heating and cooling process, which was accompanied by a volume shifting, and the transition process was further studied. This research is expected to serve as a reference for the service of micro Cu/ENIG/Sn solder joints in the electronic industry.

Structural characteristics, oxidation performance and failure mechanism of thermal barrier coatings fabricated by atmospheric plasma spraying and detonation gun spraying

In recent years, thermal barrier coatings (TBCs) are widely applied to the surface of gas-turbine engines to prolong the service life of high temperature components. The increase in raw material requirements and costs has led to the search for an alternative, cheaper ceramic based material to yttria stabilized zirconia (YSZ), which is the traditional TBC top coating material. In this study, CoNiCrAlY metallic bond coating powders were deposited on Ni-based superalloy substrates by the detonation gun (D-gun) process. Commercial YSZ and blast furnace slag (industrial waste) powders were deposited on the bond coating by atmospheric plasma spraying (APS) technique. TBCs were subjected to isothermal oxidation tests for 8, 24, 50, and 75 h at 800 °C. The microstructural properties of the TBCs were evaluated comparatively using advanced characterization techniques before and after oxidation tests. It has been observed that the coatings produced using BFS material have a potential to be used in different types of industries as a low-cost and environmental solution against high temperature oxidation conditions.

High-temperature corrosion behavior of C276 alloy, 1.4529 steel and laser-cladding 1.4529 coating under the synergistic action of deposited chloride salt and HCl-containing atmosphere

The corrosion behavior and mechanism of C276 alloy, 1.4529 steel (9 S) and its laser-cladding coating (9 C) in a simulated waste incineration environment were studied by isothermal corrosion tests. The results show 9 C and 9 S have comparable corrosion resistance to C276 at 550 °C, and they are well protected by the mixed product layer rich in Fe and Cr. A loose and porous product layer caused the corrosion resistance of C276 to be lower than expected. At 700 °C, all three materials underwent severe high-temperature electrochemical corrosion and activated oxidation, forming a Ni-rich micro-nano porous surface and multilayer corrosion products.