A kind of ceramic slurry was prepared and sprayed onto the surface of 9Ni steel at room temperature. The coating layer will not only reduce the depth of the formed Ni-enriched entanglement at high temperature but also...A kind of ceramic slurry was prepared and sprayed onto the surface of 9Ni steel at room temperature. The coating layer will not only reduce the depth of the formed Ni-enriched entanglement at high temperature but also have an excellent ability to resist oxidation of the 9Ni steel. Compared to bare specimen, the depths of the entanglement of the coated 9Ni specimen could be successfully reduced by 74.1% and the oxidation loss be decreased by 62.3% by heating at 1 250 ℃ for 60 min. In addition, the coated specimen indicates no trace of oxide pegs. It proves that the coating has outstanding improvement to internal oxidation resistance. Some characterization methods such as metalloscopy, XRD, XPS, SEM and EDX have been used to reveal a possible protective mechanism. The result shows that the coating layer reacts with the iron oxide to form Mg Fe2O4 on the surface of the coated specimen, which could provide a smaller diffusion coefficient rate of Fe ion. The coating with a low cost and easy implementation is promisingly applicable in the slab-reheating process of the 9Ni steel.展开更多
A coating of composition Si-40Mo (wt pct) was prepared by fused slurry coating method on the two-dimensional carbon/carbon (2D-C/C) composite to improve oxidation resistance. In the procedure of the fabrication, pure ...A coating of composition Si-40Mo (wt pct) was prepared by fused slurry coating method on the two-dimensional carbon/carbon (2D-C/C) composite to improve oxidation resistance. In the procedure of the fabrication, pure St slurry inner layer in the pre-coating was necessary to apply because of infiltration of liquid Si into the substrate during the sintering. The coating consists of Si continuous phase and MoSi2 particles. In addition, the infiltration of Si into the substrate and the SiC reaction layer between the coating and the C/C composite were observed. Oxidation behavior of coated and uncoated C/C composites was studied in cyclic mode. The oxidation resistance and the thermal shock resistance of the Si-Mo fused slurry coating were quite excellent at 1370℃.展开更多
The formation of protective multifunctional coatings on magnesium alloy MA8 using plasma electrolyt- ic oxidation （PEO） in an electrolytic system containing nanosized particles of titanium nitride was investigated. ...The formation of protective multifunctional coatings on magnesium alloy MA8 using plasma electrolyt- ic oxidation （PEO） in an electrolytic system containing nanosized particles of titanium nitride was investigated. Electrochemical and mechanical properties of the obtained layers were examined. It was established that microhardness of the coating with the nanoparticle concentration of 3 gl-1 increased twofold （4.2 ± 0.5 GPa）, while wear resistance decreased （4.97 × 10-6 mm3 N-1 m-1）, as compared to re- spective values for the PEO-coating formed in the electrolyte without nanoparticles （2.1 ± 0.3 GPa, 1.12 × 10.5 mm3 N-1 m-1）.展开更多
Yttrium silicate, for its high oxidation resistance, is an important candidate for protective coating for carbon-fiber-reinforced composites at temperatures above 1600 ℃. A novel method, consisting of coprecipitation...Yttrium silicate, for its high oxidation resistance, is an important candidate for protective coating for carbon-fiber-reinforced composites at temperatures above 1600 ℃. A novel method, consisting of coprecipitation, spray-drying, heat-treatment and plasma-densification, is developed to prepare Y2SiO5 powders for thermal-spraying. The composition, morphology and flowability of the synthesized Y2SiO5 powders are investigated by XRD, SEM and Hall Flowmeter, respectively. The results show that the synthesized Y2SiO5 powders are nearly spherical with high purity. The apparent density and flowability of the Y2SiO5 powders are 1.87 g/cm^3 and 37 s/50 g, respectively, which lead to a high deposition efficiency of up to 80700 for atmospheric plasma spraying.展开更多
基金Funded by the Key Projects in the National Science &Technology Pillar Program in the Twelfth Five-year Plan Period(No.2012BAB08B04)the National Natural Science Foundation of China(No.51202249)
文摘A kind of ceramic slurry was prepared and sprayed onto the surface of 9Ni steel at room temperature. The coating layer will not only reduce the depth of the formed Ni-enriched entanglement at high temperature but also have an excellent ability to resist oxidation of the 9Ni steel. Compared to bare specimen, the depths of the entanglement of the coated 9Ni specimen could be successfully reduced by 74.1% and the oxidation loss be decreased by 62.3% by heating at 1 250 ℃ for 60 min. In addition, the coated specimen indicates no trace of oxide pegs. It proves that the coating has outstanding improvement to internal oxidation resistance. Some characterization methods such as metalloscopy, XRD, XPS, SEM and EDX have been used to reveal a possible protective mechanism. The result shows that the coating layer reacts with the iron oxide to form Mg Fe2O4 on the surface of the coated specimen, which could provide a smaller diffusion coefficient rate of Fe ion. The coating with a low cost and easy implementation is promisingly applicable in the slab-reheating process of the 9Ni steel.
文摘A coating of composition Si-40Mo (wt pct) was prepared by fused slurry coating method on the two-dimensional carbon/carbon (2D-C/C) composite to improve oxidation resistance. In the procedure of the fabrication, pure St slurry inner layer in the pre-coating was necessary to apply because of infiltration of liquid Si into the substrate during the sintering. The coating consists of Si continuous phase and MoSi2 particles. In addition, the infiltration of Si into the substrate and the SiC reaction layer between the coating and the C/C composite were observed. Oxidation behavior of coated and uncoated C/C composites was studied in cyclic mode. The oxidation resistance and the thermal shock resistance of the Si-Mo fused slurry coating were quite excellent at 1370℃.
基金financially supported by the Russian Science Foundation(Project No.14-33-00009)the Russian Federation Government(Federal Agency of Scientific Organizations)
文摘The formation of protective multifunctional coatings on magnesium alloy MA8 using plasma electrolyt- ic oxidation （PEO） in an electrolytic system containing nanosized particles of titanium nitride was investigated. Electrochemical and mechanical properties of the obtained layers were examined. It was established that microhardness of the coating with the nanoparticle concentration of 3 gl-1 increased twofold （4.2 ± 0.5 GPa）, while wear resistance decreased （4.97 × 10-6 mm3 N-1 m-1）, as compared to re- spective values for the PEO-coating formed in the electrolyte without nanoparticles （2.1 ± 0.3 GPa, 1.12 × 10.5 mm3 N-1 m-1）.
基金supported by the National Fundamental Research Program (No. A1320070102)
文摘Yttrium silicate, for its high oxidation resistance, is an important candidate for protective coating for carbon-fiber-reinforced composites at temperatures above 1600 ℃. A novel method, consisting of coprecipitation, spray-drying, heat-treatment and plasma-densification, is developed to prepare Y2SiO5 powders for thermal-spraying. The composition, morphology and flowability of the synthesized Y2SiO5 powders are investigated by XRD, SEM and Hall Flowmeter, respectively. The results show that the synthesized Y2SiO5 powders are nearly spherical with high purity. The apparent density and flowability of the Y2SiO5 powders are 1.87 g/cm^3 and 37 s/50 g, respectively, which lead to a high deposition efficiency of up to 80700 for atmospheric plasma spraying.
