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In this study, 37 kinds of high-entropy pyrochlore/fluorite ceramics with equiatomic multicomponent compositions were successfully synthesized and the process of phase transformation was also investigated. Eventually, the experimental results show that 33 among the high-entropy compounds exhibit a single pyrochlore/fluorite structure with all cations randomly and uniformly distributed at A and B sites. Meanwhile, the ionic radii, valence, and size disorder may be the main driving forces for the formation of single-phase high-entropy pyrochlore/fluorite oxides. Furtherly, the average radius ratio(rA/rB) is the main factor of the pyrochlore/fluorite phase transformation. And when the average radius ratio(rA/rB) extends from 1.46 to 1.78, the high-entropy pyrochlore structure is stable. When the average radius ratio rA/rB is less than 1.46, it transforms into the defective fluorite structure. This study not only further expands the high-entropy pyrochlore family and but also is expected to guide the design of high-entropy pyrochlore through composition customization.

Dense SiC ceramics with a high alignment of graphene nanoplatelets (GNPs) were fabricated via a liquid-phase hot pressing (HP) process. The effects of GNPs on the phase composition, microstructure evolutions, mechanical and thermal properties of SiC ceramics were analyzed in detail. As the GNPs content increased from 0 to 3 wt %, the density and hardness of the SiC/GNPs composites decreased monotonically, whereas the flexural strength, fracture toughness and thermal conductivity increased initially and then decreased. The decrease in density and hardness is due to the low density and low hardness of GNPs themselves. The increase in thermal conductivity is mainly due to electron thermal transmission and the widening effect of phonon thermal transmission channel by the textured GNPs. The main strengthening and toughening mechanisms include fine grain strengthening, dislocation strengthening, crack bridging, crack deflection and crack termination. The SiC/GNPs composites sintered under uniaxial pressure condition (HP) display anisotropic thermal and mechanical properties. The anisotropic thermal conductivities of the SiC/GNPs composites are likely due to in plane GNPs parallel to the direction of heat flow, while through plane GNPs are perpendicular to the direction of heat flow. The anisotropy in mechanical properties of the SiC/GNPs composites are due to the through plane GNPs preferentially oriented to intersect the cracks, while the in plane GNPs preferentially oriented to parallel the cracks.

Porous SiOC ceramic was successfully prepared by pyrolysis of dimethylsilicone oil, silane coupling agent and melamine foam. The microwave absorbing properties of porous SiOC were studied for the first time. At the matching layer thickness of 3.0 mm, the paraffin-based composite with porous SiOC displays a minimum reflection coefficient (RC) of −39.13 dB (11.76 GHz) and an effective absorption bandwidth (EAB) of 4.64 GHz which are much larger than that of paraffin-based composite with ordinary SiOC. It is found that the porous structure of SiOC is crucial to achieve its high microwave absorption performance by improving both the polarization loss and conduction loss. The enhanced polarization loss is originated from the dipole polarization and interfacial polarization, while the improvement of conduction loss is attributed to the carbon skeleton of porous SiOC. These results indicate that porous SiOC ceramic is a promising candidate for high-performance ceramic-based microwave absorbing materials.

The classification of individuals into different racial groups provides a precondition for racial bias in cognition and behaviour, but how the brain enables spontaneous racial categorization is not fully understood. Here using multimodal brain imaging measures, including electroencephalography, functional magnetic resonance imaging and magnetoencephalography, we probe the neural dynamics of racial categorization by quantifying the repetition suppression of neural responses to faces of different individuals of each racial group (that is, Asian, black or white). We show that categorization of other-race faces engages early two-stage dynamic activities in neural networks consisting of multiple interactive brain regions. Categorization of same-race faces, however, recruits a different and simple network in a later time window. Dynamic neural activities involved in racial categorization predict racial biases in face recognition and altruistic intention. These results suggest that there are distinct neural dynamics by which the brain sorts people into different racial groups as a social ground for cognition and action.

Ti3AlC2 ceramics were successfully joined with TiO2 and Nb2O5 respectively as interlayers via solid-state diffusion bonding at 1300 °C. The joints bonded with TiO2 and Nb2O5 exhibit distinct microstructures. Two continuous thin Al2O3 oxidation layers with a thickness around 1 μm were formed in the joints bonded with TiO2. Between the oxidation layers there exists a dense oxycarbide (TiC1-xOx) layer. For the joint bonded with Nb2O5, a dense bonding layer with Nb2AlC and Nb4AlC3 grains surrounded by thin Al2O3 oxidation layers at the grain boundaries were obtained. The shear strength of the final joints shows clear dependences on both the thickness and microstructure of the joints. Smaller joint thickness and the microstructure with complex phases favour for higher shear strength. Those result implies that bonding with oxides is a practical and efficient method for joining Ti3AlC2.

Oxygen 18 was used as a tracer to quantify anion diffusion in thin-film UO2 using secondary ion mass spectroscopy to measure one-dimensional depth profiles. Both thermal and heavy ion bombardment (1.8 MeV Kr+) treatments were employed over a temperature range from 295 K to 623 K. Textured and single-crystal thin-film samples were grown using reactive-gas magnetron sputtering at ambient temperature. Both microstructures resulted in similar thermal activation energies, Ea = 0.2 eV. This activation energy is significantly lower than the known value for intrinsic anion vacancy-self diffusion in stoichiometric UO2.00 (Ea = 2.5 eV). We attribute this to an interstitialcy mechanism in our hyper-stoichiometric films. The activation energy for irradiated textured films was approximately half that of thermal diffusion, consistent with the chemical rate theory. The opposite was true for the single-crystal microstructure (irradiated Ea = 0.36 eV). This may be due to radiation-induced changes in the microstructure. The mixing parameter was quantified on the anion sublattice as well, ξ = 2.1 ± 0.2 A5eV−1.

Cr coatings deposited on zircaloy-4 substrates have been oxidized in high temperature steam environment from 1000 °C to 1200 °C in this study. It has been reported by many authors that Cr coatings have exhibited excellent oxidation resistance in steam environment because of the formation of a dense and adherent Cr2O3 layer on the surface. However, we have found that in the stage when the Cr coating has completely been oxidized and approached the coating-substrate interface, it is reduced by the Zr substrate and mostly transformed into a metallic Cr layer. The mechanisms of oxidation in this stage is therefore more interesting than generally assumed and we have proposed a new model based on the diffusion and redox reaction between Zr and Cr layers in high temperature steam environment.

Fe-Fe3C@C composites are successfully synthesized via a facile pyrolysis process. Experimental results indicate that Fe-Fe3C nanoparticles are closely parceled among amorphous carbon and exhibit a core–shell structure. The obtained materials display excellent microwave absorption performance with an optimal reflection loss of − 35.6 dB at 17.2 GHz, and an effective absorbing bandwidth of 4 GHz (from 12.4 to 16.4 GHz) with the coating thickness of 2 mm. The magnetic loss derived from Fe core and dielectric loss on carbon materials as well as a good impedance matching are believed to play decisive roles for this favorable microwave absorbing properties. The composites are considered to be good candidates for microwave absorption applications.

Macroscopic parallel aligned non-woven carbon fibers were incorporated into Al2O3 composites in this study to evaluate the contribution of multiple reflections to the total electric magnetic interference (EMI) shielding. Results indicate that parallel aligned non-woven carbon fiber layers contribute significantly to the total EMI shielding effectiveness (SET) of Al2O3 composites by largely enhancing the EMI absorption, and seven parallel aligned thin non-woven carbon fiber layers finally make the almost microwave-transparent Al2O3 an excellent EMI shielding material with an EMI SET as high as 29–32 dB in the X-band frequency range. The volume fraction of carbon fibers in Al2O3 composites with seven carbon fiber layers is calculated to be only 0.5%, and therefore the EMI SE enhancement efficiency by parallel aligned large non-woven carbon fiber layers is much higher than other highly conducting nano fillers. It validates the significance of multiple reflections in achieving high EMI shielding properties in ceramic composites and provides an instructive approach to design efficient EMI shielding ceramic composites.

FeCrAl alloys have exhibited excellent oxidation resistance in high temperature steam environment. However, over the past few years, thin film FeCrAl on zircaloy substrate can only tolerate up to 1000 °C steam because of the fast diffusion between zirconium and iron. In this study, we introduce Mo as a buffer layer and significantly reduced the inter-diffusion of zirconium and iron. The 7-micron thick FeCrAl coatings have shown excellent oxidation resistance up to 1200 °C, which is the highest temperature of thin FeCrAl coatings reported in literature. A systematic study of the oxidation behavior of FeCrAl coatings at 1000, 1100, 1200 °C is presented in this paper.

TiO2 was selected as effective sintering aid for pressureless sintering of Ti3AlC2 ceramics in this study. The addition of only 5 wt% TiO2 largely promotes the densification and nearly dense Ti3AlC2 ceramic was obtained by pressureless sintering at 1500 °C. Significant strengthening and toughening effects were observed with the addition of TiO2. High Vickers hardness, flexural strength and fracture toughness of 3.22 GPa, 298 MPa and 6.2 MPa m−1/2, respectively, were achieved in specimen pressureless sintered with 10 wt% TiO2. Additionally, the addition of 5 wt% TiO2 had no deleterious effect on the excellent oxidation resistance of Ti3AlC2 ceramic under 1200 °C water vapor atmosphere, while addition of 10 wt% TiO2 accelerates the oxidation rate by two orders of degree.

Identifying biomarkers that predict mental states with large effect sizes and high test-retest reliability is a growing priority for fMRI research. We examined a well-established multivariate brain measure that tracks pain induced by nociceptive input, the Neurologic Pain Signature (NPS). In N = 295 participants across eight studies, NPS responses showed a very large effect size in predicting within-person single-trial pain reports (d = 1.45) and medium effect size in predicting individual differences in pain reports (d = 0.49). The NPS showed excellent shortterm (within-day) test-retest reliability (ICC = 0.84, with average 69.5 trials/person). Reliability scaled with the number of trials within-person, with ≥60 trials required for excellent test-retest reliability. Reliability was tested in two additional studies across 5-day (N = 29, ICC = 0.74, 30 trials/person) and 1-month (N = 40, ICC = 0.46, 5 trials/person) test-retest intervals. The combination of strong within-person correlations and only modest between-person correlations between the NPS and pain reports indicate that the two measures have different sources of between-person variance. The NPS is not a surrogate for individual differences in pain reports but can serve as a reliable measure of pain-related physiology and mechanistic target for interventions.Significance statementCurrent efforts towards translating brain biomarkers require identifying brain measures that can strongly and reliably predict outcomes of interest. We systematically examined the performance of a well-established brain activity pattern, the Neurological Pain Signature (NPS), in a large and diverse sample of participants. The NPS showed excellent reliability, and the reliability scaled with the number of trials within-person. The NPS responses showed strong correlations with pain reports at the within-person level but only modest correlations at the between-person level. The findings suggest that the NPS is not a surrogate for individual differences in pain reports but can serve as a reliable measure of a pain-related physiological target.Author NoteThis project was supported by grants R01MH076136 (T.D.W.), R01DA046064, R01EB026549, and R01DA035484. Elizabeth A. Reynolds Losin was supported by a Mentored Research Scientist Development award from National Institute On Drug Abuse of the National Institutes of Health (K01DA045735). Lauren Y. Atlas was supported in part by funding from the Intramural Research Program of the National Center for Complementary and Integrative Health. Yoni K. Ashar was supported by NCATS Grant # TL1-TR-002386. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. Code for all analyses and figures is available at https://github.com/XiaochunHan/NPS_measurement_properties. Data for all analyses and figures is available at https://osf.io/v9px7/.

Supplemental material, sj-pptx-1-pss-10.1177_0956797621989730 for Functional MRI Can Be Highly Reliable, but It Depends on What You Measure: A Commentary on Elliott et al. (2020) by Philip A. Kragel, Xiaochun Han, Thomas E. Kraynak, Peter J. Gianaros and Tor D. Wager in Psychological Science

Civilian casualties occur during military attacks. Such ‘collateral damage’ is prohibited by international laws but increases with substantial consequences when intergroup conflict escalates. Here, we investigate cognitive and neural bases of decision-making processes resulting in civilian harm, using a task that simulates punishment decision-making during intergroup conflict. We test two groups of Chinese participants in a laboratory setting, and members of two ethnic groups (Jewish and Palestinian) in Israel. The results dissociate two psychological constructs, harm preference and harm avoidance, which respectively characterize punishment decision-making related to outgroup combatants and outgroup noncombatants during intergroup conflict. In particular, individuals show decreased avoidance of harming outgroup noncombatants when conflict escalates. Brain imaging (functional magnetic resonance imaging) reveals that decreased harm avoidance is predicted by inhibition of the left middle frontal activity during selection of punishment decisions. Our findings provide insight into the cognitive and neural bases of decision-making involving civilian harm during intergroup conflict. During intergroup conflict, decision-makers must often consider whether their actions will harm noncombatant members of the outgroup. Here, Han et al. examine cognitive and neural processes during ‘collateral damage’ scenarios, revealing decreased avoidance of harm to outgroup civilians when conflict escalates.

Civilian casualties occur during military attacks. Such 'collateral damage' is prohibited by international laws but increases with substantial consequences when intergroup conflict escalates. Here, we investigate cognitive and neural bases of decision-making processes resulting in civilian harm, using a task that simulates punishment decision-making during intergroup conflict. We test two groups of Chinese participants in a laboratory setting, and members of two ethnic groups (Jewish and Palestinian) in Israel. The results dissociate two psychological constructs, harm preference and harm avoidance, which respectively characterize punishment decision-making related to outgroup combatants and outgroup noncombatants during intergroup conflict. In particular, individuals show decreased avoidance of harming outgroup noncombatants when conflict escalates. Brain imaging (functional magnetic resonance imaging) reveals that decreased harm avoidance is predicted by inhibition of the left middle frontal activity during selection of punishment decisions. Our findings provide insight into the cognitive and neural bases of decision-making involving civilian harm during intergroup conflict.

Revenge during intergroup conflict is a human universal, but its neurobiological underpinnings remain unclear. We address this by integrating functional MRI and measurements of endogenous oxytocin in participants who view an ingroup and an outgroup member's suffering that is caused mutually (Revenge group) or by a computer (Control group). We show that intergroup conflict encountered by the Revenge group is associated with an increased level of oxytocin in saliva compared to that in the Control group. Furthermore, the medial prefrontal activity in response to ingroup pain in the Revenge group but not in the Control group mediates the association between endogenous oxytocin and the propensity to give painful electric shocks to outgroup members, regardless of whether they were directly involved in the conflict. Our findings highlight an important neurobiological correlate of revenge propensity, which may be implicated in conflict contagion across individuals in the context of intergroup conflict.

Graphene nanoplatelets (GNPs) were successfully incorporated into silicon carbide (SiC) ceramic matrix in a self-aligned pattern and the obtained materials displayed extremely high value of shielding effectiveness (SE) over 40 dB by adding only 3 wt.% GNPs, which was the highest SE value in all SiC-based composites reported in literature up to now. It was found that the texture distribution of GNPs was crucial to achieve the high electromagnetic interference shielding performance of SiC/GNPs composites, which can contribute to the significant improvement of both absorption and reflection. The improved absorption originated from the formation of network of mini capacitors comprised of self-aligned GNPs and multiple reflections. The improvement of reflection was attributed to the high electrical conductivity of the composite due to the introduction of GNPs. These results indicate that SiC/GNPs composites can be used as high-performance ceramic-based EMI shielding materials.

To explore the essence of spleen deficiency and dampness in Chinese medicine by successfully constructing a rat model with this syndrome. Methods: Rat models with the syndrome of dampness and spleen deficiency were established with the use of a high-fat, low-protein diet and excessive fatigue induced by loaded swimming. A total of 25 common clinical serological markers were tested. The T test, rank test, and partial least squares regression-discriminant analysis were used to analyze the data. Results: Total protein, albumin, motilin, interferon-γ, interleukin-2, immunoglobulin A, immunoglobulin G, and complement 3 levels in the model rats were lower than those in the control group (P = 0.029, P = 0.032, P < 0.001, P < 0.001, P < 0.001, P < 0.001, P < 0.001, P < 0.001, respectively). The serum creatinine, total cholesterol, aldosterone, antidiuretic hormone, gastrin, interleukin-4, somatostatin, atrial natriuretic peptide, and vasoactive intestinal peptide levels in the model group were higher than those in the control group (P < 0.001, P = 0.015, P < 0.001, P < 0.001, P < 0.001, P < 0.001, P < 0.001, P < 0.001, P < 0.001, respectively). There was no statistical difference between the two groups in aspartate transaminase, alanine aminotransferase, globulin, albumin/globulin, blood urea nitrogen, high-density lipoprotein, and low-density lipoprotein. The model animal syndrome used two important variables in analysis with partial least squares regression-discriminant analysis. At the same time, the two dimensions were difficult to distinguish for each biological index. Conclusion: Spleen deficiency is often associated with dampness. The index that represents spleen deficiency can also represent dampness. Cytokines, immunoglobulins, and gastrointestinal hormones play a major causative role in both spleen deficiency and dampness.

Emotions are at the core of human cognition and behavior. Traditionally, emotions have been classified dichotomously as being either positive or negative. However, recent behavioral research (An et al., 2017) suggests that emotions contain both positivity and negativity. The current work investigated neural correlates of experiencing positive and negative emotions in response to happy and sad photos. Functional MRI revealed the precuneus and posterior cingulate cortex showed stronger activation when experiencing positivity compared to negativity of sadness, but not happiness, whereas the bilateral cerebellum showed greater response to positivity than negativity regardless of emotion. Results suggest that there are similarities and differences in the neural activation of positivity and negativity of happiness and sadness, consistent with previous findings (An et al., 2017). Emotion from both the neural and psychological perspectives were investigated. Further implications are discussed.

A ZrO2/FeCrAl bilayer coating was prepared on Zr-4 alloy. Plasma electrolytic oxidation (PEO) was used to synthesize the ZrO2 buffer layer and magnetron sputtering was used to deposit the FeCrAl outer layer. The oxidation resistance of the ZrO2/FeCrAl coated Zr-4 alloy was investigated by using 1000 °C steam oxidation tests and was compared with the mono-layer FeCrAl coated and uncoted Zr-4 alloys. Morphologies, phase compositions and elemental distributions of the ZrO2/FeCrAl and FeCrAl coated Zr-4 alloys before and after the steam oxidation tests were characterized by SEM, XRD and EDX mapping and line scans. Results indicated that the introduction of the ZrO2 buffer layer effectively eliminated the high temperature inter-diffusion between FeCrAl and Zr-4 alloy, and consequently improved the adherence and integrity of the FeCrAl layer after the 1000 °C steam oxidation. As a result, the parabolic rate constant of the ZrO2/FeCrAl coated Zr-4 alloy was decreased by about 20 times compared with that of the uncoated and FeCrAl coated Zr-4 alloys in 1000 °C steam environment.

In this study, the compact and uniform CrSi (Cr0.92Si0.08, Cr0.85Si0.15, Cr0.65Si0.35) coatings have been deposited on zircaloy-4 substrates by magnetron sputtering technique, and their oxidation performances in steam environment have been investigated at 1200°C for 60 min. Microstructures and phase compositions of coatings before and after oxidation indicate that CrSi coatings exhibit protective behavior. The dense Cr2O3 oxide layer on CrSi coatings can significantly improve the oxidation resistance, and their weight gains are reduced. The Cr0.92Si0.08 coating shows the optimum performance due to the integrality and protectiveness of the Cr2O3 oxide layer.

In order to improve the problems of serious energy waste and low utilization rate, this paper designs and builds an experimental platform for a pulsating heat pipe type phase change heat storage device. The temperature changes with time in the heat storage and release device of the barium hydroxide octahydrate phase change material under different working conditions is studied. The results show that during the heat release process, when the pulsating heat pipe is filled with water, the cooling water temperature rises to the highest, and the heat recovery rate is as high as 64%. Otherwise, the initial temperature of the cooling water during the heat release process is studied. Result shows that the initial temperature of the cooling water increases, the longer the latent heat of phase change and the total heat release time, and the higher the temperature rise of the cooling water. The experimental design of this paper can provide a reference for researchers in related fields.

Cr coatings deposited on zircaloy substrates generally exhibit (110) and (200) preferred orientations, which in turn affects the microstructure and oxidation performance of coatings. In this study, the preferential orientation of Cr coatings has been regulated in order to enhance the oxidation resistance of Cr coatings. For the pristine coatings, the deposition rate and surface morphologies depend strongly on the bias voltage and Ar pressure. While the evolutions of the texture coefficients are affected significantly by temperature, bias voltage and Ar pressure, especially for the (110) texture. The oxidation resistance of coatings with different texture has been investigated according to the energy-dispersive X-ray spectrometry. After oxidized in steam at 800 ℃ for 1 h, a transition layer and dispersed particles with higher oxygen content have been discovered. In addition, coatings deposited at pressure higher than 1.0 Pa exhibit through-film cracks and the zirconium substrates have been partially oxidized.

Objectives To assess the value of next-generation sequencing (NGS) technology in early diagnosis of patients with tuberculous meningitis (TBM). Methods 56 patients with clinically suspected TBM who came to Shandong Provincial Chest Hospital from February 2, 2018 to August 2, 2018 were prospectively included, and the clinical diagnosis and treatment outcomes were followed up. NGS was performed for the cerebrospinal fluid specimens submitted for test on the BGISEQ-100 platform of Tianjin Huada Gene Research Institute and the obtained pathogen sequences were compared with the pathogen data to get the final results. The NGS results were positive for detecting the unique matching sequence of the Mycobacterium tuberculosis (MTB) complex and negative for no unique matching sequence. Patients confirmed with TBM should have at least one of the following four items: cerebrospinal fluid MTB culture positive, smear positive, Xpert MTB/RIF test positive, or MTB nucleic acid polymerase chain reaction (PCR) test positive; clinically diagnosed patients were those with clinically suspected TBM and effective anti-tuberculosis treatment; non-TBM patients were those with other pathogenic basis or clinical exclusion of TBM. The sensitivity and specificity of NGS in early diagnosis of TBM were analyzed. Results 22 patients were confirmed with TBM, of which 13 were positive for Xpert MTB/RIF test, 6 were positive for cerebrospinal fluid MTB culture, 5 were positive for MTB nucleic acid PCR test, 12 patients were clinically diagnosed with TBM, and there were 16 cases of non-TBM patients. Among confirmed and clinically diagnosed patients, 20 cases of MTB complex were detected by NGS technology, with a sensitivity of 58.8% (20/34) and specificity of 100% (16/16). Among confirmed patients, the sensitivity of NGS was 63.6% (14/22). Of the 50 specimens that were simultaneously subjected to traditional methods, Xpert MTB/RIF test and NGS, the specificity of the three methods was 100% (16/16) based on clinical diagnosis, and the sensitivity was 29.4% (10/34), 38.2% (13/34), and 58.8% (20/34) respectively. The difference of sensitivity between the first two detection methods and NGS was statistically significant (McNemar test, p = 0.013, x2 = 5.786 and p = 0.065, x2 = 3.273). The sensitivity of traditional methods combined with NGS was as high as 82.4% (28/34). Conclusions NGS technology could rapidly detect the MTB complex in cerebrospinal fluid with significant sensitivity and specificity, which could be used as an early diagnosis index of TBM. NGS combined with MTB culture could increase the detection rate.

Empathy has been supposed to be a proximate mechanism of altruistic behavior. We investigated whether empathy for pain drives actions without altruistic effects and how such actions modulate neural responses to others’ pain. In two experiments, we asked healthy adults to press a button for no reason when viewing video clips showing faces with pain expressions receiving needle penetration or faces with neutral expressions receiving a cotton swab touch. Experiment 1 found that participants pressed a button with greater response force when watching painful than non-painful stimuli. Participants who reported greater unpleasant feelings pressed the button harder when viewing painful stimuli. Experiment 2 revealed that passively viewing painful vs non-painful stimuli increased blood-oxygen-level-dependent signals in the middle cingulate cortex, supplementary motor cortex, and bilateral second somatosensory and inferior frontal cortex, which, however, were reduced by the action of button press without altruistic effects. In addition, individuals who reported higher personal distress illustrated greater decrease of the second somatosensory activity induced by button press. Our results indicate that empathy for pain motivates simple actions without altruistic effects that in turn reduce neural responses to others’ pain, suggesting a functional role of action execution in self distress relief when viewing others’ suffering.

Iron-chromium-aluminum (FeCrAl) coatings deposited on Zircaloy 2 (Zy2) and yttria-stabilized zirconia (YSZ) by magnetron sputtering have been tested with respect to oxidation weight gain in high-temperature steam. In addition, autoclave testing of FeCrAl-coated Zy2 coupons under pressure-temperature-dissolved oxygen coolant conditions representative of a boiling water reactor (BWR) environment has been performed. Four different FeCrAl compositions have been tested in 700 °C steam; compositions that promote alumina formation inhibited oxidation of the underlying Zy2. Parabolic growth kinetics of alumina on FeCrAl-coated Zy2 is quantified via elemental depth profiling. Autoclave testing under normal BWR operating conditions (288 °C, 9.5 MPa with normal water chemistry) up to 20 days demonstrates observable weight gain over uncoated Zy2 simultaneously exposed to the same environment. However, no FeCrAl film degradation was observed. The 900 °C eutectic in binary Fe–Zr is addressed with the FeCrAl-YSZ system.

Cr coatings have been deposited on the outer surface of zircaloy-4 tube with well control of thickness variations along the tube axis. A series of samples have been oxidized in high temperature steam environment at 1200 °C for different durations. Cr2O3 layers are formed on the surface of the Cr coatings after high temperature oxidation, however, we have found that the thickness of the Cr2O3 layers increases first, and then decreases. The reason is because the Cr2O3 is reduced by the zirconium substrate when the thickness of Cr2O3 reaches its maximum. More detailed study revealed that the entire process can be divided into three stages: initial oxidation stage (I); reduction stage (II); and the oxidation of the sub-coating zirconium at a lower rate than the uncoated Zry4 (III). In addition, precipitation of secondary phases both within the coatings and the zirconium substrate has been studied in detail which plays an important role during the oxidation process. Therefore, the oxidization behavior of the Cr-Zr system is more complex than generally assumed. This study has provided sufficient experimental evidences for the redox reaction between the Cr coating and Zry4 substrate. Diffusion channels of oxygen ions during the reduction reaction have also been studied systematically.