To improve the ablation resistance of carbon/carbon (C/C) composites, tungsten (W) coating with thickness of 1.2 mm was applied by atmospheric plasma spraying. The antiablation property of the coated composites was evaluated by oxyacetylene flame ablation experiments. The phase composition of the coating was investigated by a combination of x-ray diffraction analysis and scanning electron microscopy with energy-dispersive x-ray spectroscopy analysis. The ablation resistance of the coated C/C substrates was compared with that of uncoated C/C composites and C/C-CuZr composites after ablation for 30 s. The properties of the coated C/C composites after ablation time of 10, 30, 60, 90, 120, and 180 s were further studied. The results indicated that the mass and linear ablation rates of the W-coated C/C composites were lower than those of uncoated C/C or C/C-CuZr composites after ablation for 30 s. The coating exhibited heat stability after 120 s of ablation, with mass loss and linear ablation rates of 7.39 x 10(-3) g/s and 3.50 x 10(-3) mm/s, respectively. However, the W coating became ineffective and failed after ablation for 180 s. Three ablation regions could be identified, in which the ablation mechanism of the coating changed from thermochemical to thermophysical erosion to mechanical scouring with increasing ablation time.
Kuznetsov, Vitaly V.
Pavlov, Leonid N.
Vinokurov, Eugene G.
Filatova, Elena A.
Kudryavtsev, Vladimir N.
Cr–C–W coatings were deposited from organo-aqueous solutions containing dimethylformamide by electrolysis. The obtained deposits were studied by the modern physical methods: X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), time-of-flight secondary ion mass spectrometry (SIMS), and inductively coupled plasma atomic emission spectroscopy (ICP-AES). The corrosion of Cr–C–W electrolytic deposits was studied in the solutions of sulfuric acid, sodium chloride, and hydrochloric acid. Cr–C–W coatings demonstrated higher corrosion resistance compared with chromium deposits. It was suggested that the decrease of the corrosion rate is caused by the formation of the thin layer enriched with tungsten and its oxides at the surface of the Cr–C–W alloy. This assumption was confirmed by both XPS and SIMS.
Kuznetsov, Vitaly V.; Pavlov, Leonid N.; Vinokurov, Eugene G.; Filatova, Elena A.; Kudryavtsev, Vladimir N.
Cr-C-W coatings were deposited from organo-aqueous solutions containing dimethylformamide by electrolysis. The obtained deposits were studied by the modern physical methods: X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), time-of-flight secondary ion mass spectrometry (SIMS), and inductively coupled plasma atomic emission spectroscopy (ICP-AES). The corrosion of Cr-C-W electrolytic deposits was studied in the solutions of sulfuric acid, sodium chloride, and hydrochloric acid. Cr-C-W coatings demonstrated higher corrosion resistance compared with chromium deposits. It was suggested that the decrease of the corrosion rate is caused by the formation of the thin layer enriched with tungsten and its oxides at the surface of the Cr-C-W alloy. This assumption was confirmed by both XPS and SIMS.
Marzenna Galar
Jarosław Piszcz
Anna Szumowska
Łukasz Bołkun
Janusz Kłoczko (Prof. dr hab. med.)
| Figures/TablesFigures/Tables | ReferencesReferencesSTRESZCZENIERozwojowi ostrych białaczek już w momencie diagnozy towarzyszy subkliniczna aktywacja krzepnięcia. Zaburzenia hemostazy, wynikające m.in. z uszkodzenia śródbłonka i osłabionej funkcji syntetycznej wątroby, nie zawsze manifestują się jawną skazą krwotoczną lub chorobą zakrzepową. Wydolność mechanizmów kompensacyjnych na poziomie układu antykoagulacyjnego białka C - zapewnia równowagę hemostatyczną między czynnikami prozakrzepowymi i prokrwotocznymi. Badaniami objęto 20 chorych z nowo rozpoznanymi ostrymi białaczkami. W początkowym okresie rozwoju choroby obserwowano obniżenie stężeń antykoagulacyjnych białek syntezowanych w wątrobie (PC, PS) oraz wzrost sTM i znaczne obniżenie sEPCR - białkowych markerów uszkodzenia śródbłonka naczyń.
W LIII EXAFS of WS2/C and Ni-WS2/C catalysts showed that the WS2/C catalyst contains small WS2 particles of about 7 W atoms, while the Ni-WS2/C catalyst contains larger particles. Ni K EXAFS demonstrated that the Ni atoms were present at the edges of the WS2 particles in a Ni-W-S like structure, like the Ni-Mo-S structure in Ni-MoS2/C catalysts. In the Ni-WS2/C catalysts Ni is, however, coordinated by six sulphur atoms, four at 2.22 Å and two at 2.35 Å from the Ni atom.
Creat membership
Sweep WeChat yards
