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Experimental evidence shows that CuFe2O4 exhibits excellent catalytic performance in the SCR reaction.

Cu@g-PAN/g-C3N4 exhibits excellent stability and excellent photocatalytic performance. The incorporation of g-C3N4 broadens the light absorption range.

The adhesion strength between the circuit and substrate is a key factor that affects the performance of electronics. Laser modification assisted metallization technology (LAM), which can fabricate high-adhesion metallic pattern on ceramic without masks, is generally considered as a promising selective metallizing method. However, it seems lack of the reports about how the texturing patterns affect the coating adhesion on ceramic up to now. In this paper, three kinds of texturing patterns—parallel groove texture (PGT), parallel wave texture (PWT) and square net texture (SNT) with different laser scanning spacings (D) were fabricated on ceramic substrates by laser modification, and the copper was selectively electroless-plated on the textured surface. Then, the influences of textures on the adhesion strength and fracture mechanism of copper-ceramic were studied systematically. Results indicated that the adhesion were significantly affected by the surface area, microstructures and structural defects of the textures. Compared with PGTs and PWTs, SNTs showed a more significant effect on improving the adhesion, in which a reliable obtuse-angled anchoring bond was generated at D = 60 μm (sample SN60), making the fracture take place at the copper, ceramic and copper-ceramic interface simultaneously, and the maximum adhesion strength as high as 43.2 MPa was obtained.

A TiC + mixture (TiC/Al2O3 (1:1 wt.%)) +Al2O3 self-healing triple layer coating (TLC) was designed and manufactured by our group, and the crack-filling heat treatment process had been roughly explored in the past. In this work, the accelerating test with a thick TiC + mixture (TiC/Al2O3 (1:1 wt.%)) double-layer coating (DLC) was carried out. The DLC coating warped when the heat treatment temperature was lower than 550 °C, which was rare in similar researches, and it crushed into fan-shaped pieces when the treatment temperature was higher than 650 °C. The two different spalling failures were explained by weight gain, porosity and stress analyses. The heating rate had a significant effect. The bonding strength and hydrogen permeation of the TLC samples were also tested. Remaining at 650 °C for 40 h was proved to be an optimal crack-filling heat treatment process, considering the hydrogen resistance.

High infrared emissivity coating possesses great value in practical application, whether in the military or civilian areas. In this study, B-NiCr precursor powder containing NiO, Cr2O3 and ZrB2 was calcined at 1300 °C and then used to prepare a high infrared emissivity B-NiCr coating via atmospheric plasma spraying. A large number of test methods were employed to analyze the powder and coating, including TG-DSC, XRD, FE-SEM, infrared spectrometer and so on. The result of infrared emissivity measurement indicates that the coating possesses maximum infrared emissivity of 0.908 at 1000 °C while the infrared emissivity is 0.901 after thermal shock test. Comparing with NiCr coating, Ni2CrO2(BO3) formed during calcination may be the main factor to improve the infrared emissivity of B-NiCr coating. The B-NiCr coating possesses good thermal shock resistance and can withstand 50 times thermal shock at least without falling off, from 800 °C to room temperature.

It is well-known that thermally grown oxide (TGO) deteriorates thermal barrier coating (TBC) systems after extended operating time. In this study, SiC-self-healing coatings (called “SAZ coatings” here) were investigated as a possible solution to enhance the oxidation resistance and spallation resistance of TBC systems. The self-healing-related filling and sealing effects of the proposed coatings were investigated and the oxidation resistance of the system after SAZ coating treatment was examined. To fully understand the oxidation resistance and spallation resistance mechanisms, we also conducted high-temperature cyclic oxidation tests (1100 °C) and recorded the mass gain and mass loss of samples after each cycle. Results showed that the corrosion current of YSZ/SAZ TBC samples decreased 79.23% after oxidation at 720 °C for a period of 10 h, and that 25.77% less TGO grew in YSZ/SAZ TBC samples after 20 h at 1100 °C compared to YSZ TBC samples due to the self-healing coating layer. The lifetime of YSZ/SAZ TBC was improved 58.33% compared to YSZ TBC in the high-temperature cyclic oxidation test, owing to the higher oxidation resistance and toughening effect of the SAZ coating.

In this work, tritium permeation barriers were prepared on the surface of super-clean reduced activation martensitic (SCRAM) steel by the pack cementation method. The pack cementation process was conducted by packing samples in a powder mixture consisting of titanium, ammonium chloride and alumina powder at 1000 °C for 30 min to form a titanized coating. Subsequently, the samples were nitrided in an ammonium atmosphere and then oxidized in air at 760 °C for 1 h to obtain a multilayered structure. The results showed that the as-prepared titanized coatings consisted of two layers. The exterior layer was made of TiN and the interior layer was a diffusion layer resulting from titanium atoms diffusing into the substrate. After being nitrided and then oxidized, the coatings were discovered to have transformed into a three-layered structure. The outer layer was rutile TiO2, the middle layer was Ti-N and the inner layer was Ti-C. Hydrogen permeation tests were performed on the coatings and pure matrix steels at room temperature. The results revealed that the three-layered structure coatings exhibited good barrier properties against hydrogen penetration. This three-layered structure coating may be a good material to increase the hydrogen permeation resistance of SCRAM steel.

Thermal growth oxide (TGO) leads to final failure of thermal barrier coatings (TBC) under elevated temperature operation. Researchers have considered preparing different kinds of oxidation barrier coatings for suppressing TGO growth. TiC-based self-healing coatings are one type of possible oxidation barrier coatings for TBC lifetime improvement. According to previous work and recent results, 20-wt% TiC, 40-wt% Al2O3 and 40-wt% YSZ composite self-healing coating (TAZ20) exhibited sealing and filling effects in normal atmosphere above 650 °C. Image analysis and hot corrosion tests both showed that sealing and filling effects led to porosity decline and that even melted hot corrosion salts could not penetrate healed coatings. Then, three types of TiC-based self-healing TBC and traditional TBC were prepared and their oxidation resistance at 1100 °C investigated. The results showed that the TAZ20 coatings in different structural strategies were related to different oxidation resistance. TAZ20 coatings made the protective oxidation process last longer but did not avoid the breakaway oxidation process. The TAZ20/YSZ/TAZ20 structural TBC showed the best oxidation resistance, which reduced TGO by ~50% after 20 h of high temperature oxidation. According to thermal cyclic tests, this enhanced oxidation resistance improved TBC lifetime. The lifetime of TAZ20/YSZ/TAZ20 structural TBC was ~180% that of traditional TBC. In sum, these TiC-self-healing coatings appeared very promising potential and involved a cost-effective method to protect TBC against TGO failure.

In the present study, Ti toughened ODS (ODS/Ti) steels were researched. The effects of N on the formation of Ti(C,N) at the interface of ODS matrix and Ti layer and on the final toughening effect of ODS/Ti steels were studied. 0N, 0.2N-ODS/Ti steels all present inferior tensile properties that much lower than the strength and ductility of the corresponding pure ODS steels. While 0.5N-ODS/Ti steel exhibits extraordinary tensile strength of more than 2300 MPa and strain of 13.5%. Elements interdiffusion across the interface of ODS and Ti layer causes the formation of detrimental intermetallic in Ti layer which leads to the inferior tensile properties of 0N-ODS/Ti and 0.2N-ODS/Ti steels. While the formation of a thick continuous Ti(C, N) layer at the interface of 0.5N-ODS matrix and Ti layer can limit the interdiffusion of elements and decrease the contents of brittle intermetallic. Besides, the Ti(C, N) formed at the interface which has intrinsic high strength and the high plasticity of Ti foil are assumed to have contributed to the extraordinary high strength and high ductility of 0.5N-ODS/Ti steel. The effect of multilayers’ interfaces on the toughening and strengthening mechanisms of layered ODS steel needs to be investigated at nano scale in the future.

The effects of oxidizing treatment (OT) and nitriding-oxidizing treatment (NOT) on the corrosion resistance of Fe-21Cr-9Mn alloy in liquid zinc were investigated. The results reveal that they both can significantly improve the corrosion resistance owing to the presence of an unwettable oxide layer. By comparison, NOT alloy shows a longer incubation time in liquid zinc than OT alloy due to a more high-quality oxide. The corrosion of these two modified alloys both are controlled by dissolution mechanism and localized corrosion of the oxide.

In the present study, a 9Cr-oxide dispersion strengthened steel was developed and its composite reinforced by Ta layers (ODS/Ta) was also researched. The tensile strength and total elongation of ODS steel is 934 MPa and 11% respectively. The appreciable tensile property is resulted from the bimodal grain size distribution, with micrometre-sized grains and nano-sized grains uniformly distribute in ODS matrix and a large number of nano-sized Ti V carbonitride and oxides of Y Ti in steel. The strength and total elongation of ODS/Ta steel is 1390 MPa and 13.6% respectively. More dimples are observed in ODS matrix of ODS/Ta steel than that in ODS steel, indicating better ductility. While Ta exhibits cleavage fracture due to the strong restriction by the strong interface and the ductility of ODS matrix near the interface has also been restricted. Even so, layered structure has still improved the strength and ductility. Enhanced flaw resistance by layered structure, the cracking and pulling out of Ta that dissipate energy all contribute to the improved toughness of ODS/Ta steel. In the future, interface transitional layers or another layered toughening system will be designed to generate larger toughening effect of layered ODS system.

In the present work, effect of Ta/W thickness ratio on toughening mechanisms of Ta/W multilayers was investigated. Ta/W multilayers exhibit appreciable toughness and the toughness increase with increasing thickness ratio of Ta/W. Ta/W multilayers with thickness ratio tTa/W

Thermal barrier coatings (TBCs) are extensively used to protect metallic blades in gas-turbine engines where the operating conditions include an aggressive environment at high temperatures. The most important factor controlling TBC durability is the growth of a thermally grown oxide (TGO) layer which is formed during high temperature oxidation. To improve the oxidation resistance of conventional TBC, the SiC-self-healing coating, named the SAZ coating, was prepared by air plasma spray (APS) technique on the top of the classic bilayer TBC (YSZ TBC), which consist of the bond coating (BC) and the YSZ coating. Cracks allow SiC particles locating on the crack outside surface to react with the oxygen in the atmosphere at the temperature above 720 °C resulting in healing. As oxidation progress, the crack surfaces are covered with the formed oxide. Finally, the space between the crack surfaces is completely or incompletely filled with the formed oxide. The sealing effect enhanced the oxygen diffusion resistance of SAZ coatings, therefore the partial pressure of oxygen at the BC-YSZ interface of SAZ TBC samples would be lower than of YSZ TBC samples. The oxidation and spallation resistance of the SAZ TBC samples will be enhanced because the growth rate of TGO is slower due to the low partial pressure of oxygen. The high temperature cyclic oxidation tests performed at 1127 °C was carried out to investigate the oxidation and spallation resistance of the SAZ TBC. The results demonstrated that the mass gain of SAZ TBC samples, which was related to oxidation resistance, was 63.29% of YSZ TBC samples, and the mass loss of SAZ TBC samples, which was related to spallation resistance, was 56.08% of YSZ TBC samples.

Thermal barrier coatings (TBC) are getting great importance in industry as the inlet temperature of advanced gas-turbine engines is continuously being pushed higher in order to improve efficiency. It is well known that the thermal growth oxide (TGO) could decrease the durability of the TBC. In order to slow the growth rate of TGO, oxidation barrier coatings were designed and fabricated. Among these coatings, self-healing coating is the most promising. The present study shows that TiC acts as a self-healing agent releasing its oxide (TiO2) by reaction with oxygen in air and heals the cracks/pores present in the coatings. A TiC-self-healing coating after pre-oxidation treatment in the furnace at 600 °C could suppress the growth of the detrimental oxides by the formation of a low-porosity self-healing layer at the top coat (TC)/bond coat (BC) interface. The porosity of healed coatings decreased three times from 12% to 3% as compared to the as-sprayed coating. This lower porosity could attribute to the lower growth rate of self-healing TBC. The gained weight versus the development of the TGO exhibited 30% slower oxidation rate than the conventional TBC while less than 10% oxide area percentage in BC of TiC-self-healing. The treated coatings demonstrated better oxidation resistance up to 28.8% than the conventional coatings. TiC-self-healing coatings reduce the growth rate of TGO which promote the TBC to survive twice thermal cycles at higher temperature of 1000 °C. TiC-self-healing TBCs could be considered as a promising TBC with better oxidation resistance and thermal cycle resistance.

One type of multimodal (comprised of nanometer and sub-micrometer WC particles) and two types of conventional (comprised of nanometer and sub-micrometer WC particles, respectively) WC/Co powders were deposited on AISI 304L stainless steel substrates by using high velocity oxygen fuel spraying. The use of multimodal WC particles was indicated to have a beneficial effect on the solar absorptance (α) of the WC/Co coatings. The α of the multimodal WC coating reached 0.87, which was much higher than what can be achieved by either fine (0.82) or coarse powders (0.80) alone. By microstructural analysis, the enhancement in solar absorptance of the multimodal WC/Co coating was ascribed to the layer of distributed WC particles. During the thermal spraying, the nanostructured WC particles underwent rapid melting for the large specific surface area while the aggregated powders were heated, but not necessarily melted. The molten nano-WC would fill the available pores between the softened and heated aggregates, providing a layered distribution of WC particles for the spray-deposited coating. In this condition, the light-trapping in the multimodal coating will be enhanced due to the efficient light reflection among the multimodal WC particles, which contributes to the enhancement of solar absorptance.