81 research outputs found
Investigation on microstructure and oxidation behavior of Cr-modified aluminide coating on Ξ³-TiAl alloys
Microstructure and oxidation behavior of aluminide coating has been investigated. The layers were examined by optical microscopy, scanning electron microscopy (SEM) equipped with EDS and X-ray diffraction method. The isothermal oxidation behaviors of samples were investigated at 950Β°C for 200 h. The results indicated that TiAlβ were formed on substrate. In addition, aluminide coating improved the oxidation resistance of Ξ³-TiAl alloys by forming a protective alumina scale. Moreover, during oxidation treatment the interdiffusion of TiAlβ layer with Ξ³-TiAl substrate results in depletion of aluminum in the TiAlβ layer and growth of TiAlβ layer. After oxidation treatment the coating layer maintained a microstructure with phases including TiAlβ, TiAlβ and AlβOβ.ΠΠΎΡΠ»ΡΠ΄ΠΆΠ΅Π½ΠΎ ΠΌΡΠΊΡΠΎΡΡΡΡΠΊΡΡΡΡ Π°Π»ΡΠΌΡΠ½ΡΠ΄Π½ΠΎΠ³ΠΎ ΠΏΠΎΠΊΡΠΈΠ²Ρ ΡΠ° ΠΉΠΎΠ³ΠΎ ΠΏΠΎΠ²Π΅Π΄ΡΠ½ΠΊΡ ΠΏΡΠ΄ ΡΠ°Ρ Π²ΠΈΡΠΎΠΊΠΎΡΠ΅ΠΌΠΏΠ΅ΡΠ°ΡΡΡΠ½ΠΎΠ³ΠΎ ΠΎΠΊΠΈΡΠ»Π΅Π½Π½Ρ. Π¨Π°ΡΠΈ Π°Π»ΡΠΌΡΠ½ΡΠ΄ΡΠ² ΡΠΈΡΠ°Π½Ρ Π²ΠΈΠ²ΡΠ°Π»ΠΈ Π·Π° Π΄ΠΎΠΏΠΎΠΌΠΎΠ³ΠΎΡ ΠΎΠΏΡΠΈΡΠ½ΠΎΡ ΠΌΡΠΊΡΠΎΡΠΊΠΎΠΏΡΡ, ΡΠΊΠ°Π½ΡΠ²Π½ΠΎΡ Π΅Π»Π΅ΠΊΡΡΠΎΠ½Π½ΠΎΡ ΠΌΡΠΊΡΠΎΡΠΊΠΎΠΏΡΡ (SΠΠ) Π· Π²ΠΈΠΊΠΎΡΠΈΡΡΠ°Π½Π½ΡΠΌ Π΄ΠΈΡΠΏΠ΅ΡΡΠ½ΠΎΠ³ΠΎ ΡΠ΅Π½ΡΠ³Π΅Π½ΠΎΡΠΏΠ΅ΠΊΡΡΠΎΠΌΠ΅ΡΡΠ° (EDS) ΡΠ° ΡΠ΅Π½ΡΠ³Π΅Π½ΡΠ²ΡΡΠΊΠΈΠΌ Π΄ΠΈΡΡΠ°ΠΊΡΡΠΉΠ½ΠΈΠΌ ΠΌΠ΅ΡΠΎΠ΄ΠΎΠΌ. ΠΠΈΠΏΡΠΎΠ±ΠΎΠ²ΡΠ²Π°Π½Π½Ρ ΠΏΡΠΎΠ²ΠΎΠ΄ΠΈΠ»ΠΈ ΠΏΡΠΈ 950Β°C Π²ΠΏΡΠΎΠ΄ΠΎΠ²ΠΆ 200 h. ΠΡΡΠ°Π½ΠΎΠ²Π»Π΅Π½ΠΎ, ΡΠΎ Π½Π° ΠΏΡΠ΄ΠΊΠ»Π°Π΄ΡΡ Π· ΡΠΈΡΠ°Π½ΠΎΠ²ΠΎΠ³ΠΎ ΡΠΏΠ»Π°Π²Ρ ΡΡΠ²ΠΎΡΠΈΠ²ΡΡ TiAlβ. ΠΠΎΠΊΡΠΈΠ² Π· Π°Π»ΡΠΌΡΠ½ΡΠ΄Ρ ΡΠΈΡΠ°Π½Ρ ΠΏΠΎΠΊΡΠ°ΡΡΡ ΡΡΡΠΉΠΊΡΡΡΡ Π΄ΠΎ ΠΎΠΊΠΈΡΠ»Π΅Π½Π½Ρ ΡΠΏΠ»Π°Π²ΡΠ² Π· Ξ³-TiAl, ΡΡΠ²ΠΎΡΡΡΡΠΈ Π·Π°Ρ
ΠΈΡΠ½Ρ ΠΏΠ»ΡΠ²ΠΊΡ Π· ΠΎΠΊΡΠΈΠ΄Ρ Π°Π»ΡΠΌΡΠ½ΡΡ. ΠΡΠ΄ ΡΠ°Ρ ΠΎΠΊΠΈΡΠ»Π΅Π½Π½Ρ Π΄ΠΈΡΡΠ·ΡΠΉΠ½Π° Π²Π·Π°ΡΠΌΠΎΠ΄ΡΡ TiAlβ Π· ΠΏΡΠ΄ΠΊΠ»Π°Π΄ΠΊΠΎΡ Ξ³-TiAl ΡΠΏΡΠΈΡΠΈΠ½ΡΡ Π·ΠΌΠ΅Π½ΡΠ΅Π½Π½Ρ ΠΊΡΠ»ΡΠΊΠΎΡΡΡ Π°Π»ΡΠΌΡΠ½ΡΡ Ρ ΡΠ°ΡΡ TiAlβ ΡΠ° Π·Π±ΡΠ»ΡΡΠ΅Π½Π½Ρ ΡΠ°ΡΡ TiAlβ. ΠΡΡΠ»Ρ ΠΎΠΊΠΈΡΠ»Π΅Π½Π½Ρ Π² ΠΏΠΎΠΊΡΠΈΠ²Ρ ΡΡΠ²ΠΎΡΡΡΡΡΡΡ ΠΌΡΠΊΡΠΎΡΡΡΡΠΊΡΡΡΠ° Π· ΡΠ°Π·Π°ΠΌΠΈ, ΡΠΎ ΠΌΡΡΡΡΡΡ TiAlβ, TiAlβ ΡΠ° AlβOβ.ΠΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΎ ΠΌΠΈΠΊΡΠΎΡΡΡΡΠΊΡΡΡΡ Π°Π»ΡΠΌΠΈΠ½ΠΈΠ΄Π½ΠΎΠ³ΠΎ ΠΏΠΎΠΊΡΡΡΠΈΡ ΠΈ Π΅Π³ΠΎ ΠΏΠΎΠ²Π΅Π΄Π΅Π½ΠΈΠ΅ ΠΏΡΠΈ Π²ΡΡΠΎΠΊΠΎΡΠ΅ΠΌΠΏΠ΅ΡΠ°ΡΡΡΠ½ΠΎΠΌ ΠΎΠΊΠΈΡΠ»Π΅Π½ΠΈΠΈ. Π‘Π»ΠΎΠΈ Π°Π»ΡΠΌΠΈΠ½ΠΈΠ΄Π° ΡΠΈΡΠ°Π½Π° ΠΈΠ·ΡΡΠ°Π»ΠΈ Ρ ΠΏΠΎΠΌΠΎΡΡΡ ΠΎΠΏΡΠΈΡΠ΅ΡΠΊΠΎΠΉ ΠΌΠΈΠΊΡΠΎΡΠΊΠΎΠΏΠΈΠΈ, ΡΠΊΠ°Π½ΠΈΡΡΡΡΠ΅ΠΉ ΡΠ»Π΅ΠΊΡΡΠΎΠ½Π½ΠΎΠΉ ΠΌΠΈΠΊΡΠΎΡΠΊΠΎΠΏΠΈΠΈ (SΠΠ) Ρ ΠΈΡΠΏΠΎΠ»ΡΠ·ΠΎΠ²Π°Π½ΠΈΠ΅ΠΌ Π΄ΠΈΡΠΏΠ΅ΡΡΠ½ΠΎΠ³ΠΎ ΡΠ΅Π½ΡΠ³Π΅Π½ΠΎΡΠΏΠ΅ΠΊΡΡΠΎΠΌΠ΅ΡΡΠ° (EDS) ΠΈ ΡΠ΅Π½ΡΠ³Π΅Π½ΠΎΠ²ΡΠΊΠΈΠΌ Π΄ΠΈΡΡΠ°ΠΊΡΠΈΠΎΠ½Π½ΡΠΌ ΠΌΠ΅ΡΠΎΠ΄ΠΎΠΌ. ΠΡΠΏΡΡΠ°Π½ΠΈΡ ΠΏΡΠΎΠ²ΠΎΠ΄ΠΈΠ»ΠΈ ΠΏΡΠΈ 950Β°C Π² ΡΠ΅ΡΠ΅Π½ΠΈΠ΅ 200 h. Π£ΡΡΠ°Π½ΠΎΠ²Π»Π΅Π½ΠΎ, ΡΡΠΎ Π½Π° ΠΏΠΎΠ΄ΠΊΠ»Π°Π΄ΠΊΠ΅ ΠΈΠ· ΡΠΈΡΠ°Π½ΠΎΠ²ΠΎΠ³ΠΎ ΡΠΏΠ»Π°Π²Π° ΠΎΠ±ΡΠ°Π·ΠΎΠ²Π°Π»ΡΡ TiAlβ. ΠΠΎΠΊΡΡΡΠΈΠ΅ ΠΈΠ· Π°Π»ΡΠΌΠΈΠ½ΠΈΠ΄Π° ΡΠΈΡΠ°Π½Π° ΡΠ»ΡΡΡΠ°Π΅Ρ ΡΡΠΎΠΉΠΊΠΎΡΡΡ ΠΊ ΠΎΠΊΠΈΡΠ»Π΅Π½ΠΈΡ ΡΠΏΠ»Π°Π²ΠΎΠ² ΠΈΠ· Ξ³-TiAl, ΠΎΠ±ΡΠ°Π·ΠΎΠ²ΡΠ²Π°Ρ Π·Π°ΡΠΈΡΠ½ΡΡ ΠΏΠ»Π΅Π½ΠΊΡ ΠΈΠ· ΠΎΠΊΠΈΡΠ»Π° Π°Π»ΡΠΌΠΈΠ½ΠΈΡ. ΠΠΎ Π²ΡΠ΅ΠΌΡ ΠΎΠΊΠΈΡΠ»Π΅Π½ΠΈΡ Π΄ΠΈΡΡΡΠ·ΠΈΠΎΠ½Π½ΠΎΠ΅ Π²Π·Π°ΠΈΠΌΠΎΠ΄Π΅ΠΉΡΡΠ²ΠΈΠ΅ TiAlβ Ρ ΠΏΠΎΠ΄ΠΊΠ»Π°Π΄ΠΊΠΎΠΉ Ξ³-TiAl Π²Π»Π΅ΡΠ΅Ρ ΡΠΌΠ΅Π½ΡΡΠ΅Π½ΠΈΠ΅ ΠΊΠΎΠ»ΠΈΡΠ΅ΡΡΠ²Π° Π°Π»ΡΠΌΠΈΠ½ΠΈΡ Π² ΡΠ»ΠΎΠ΅ TiAlβ ΠΈ ΡΠ²Π΅Π»ΠΈΡΠ΅Π½ΠΈΠ΅ ΡΠ»ΠΎΡ TiAlβ. ΠΠΎΡΠ»Π΅ ΠΎΠΊΠΈΡΠ»Π΅Π½ΠΈΡ Π² ΠΏΠΎΠΊΡΡΡΠΈΠΈ ΠΎΠ±ΡΠ°Π·ΡΠ΅ΡΡΡ ΠΌΠΈΠΊΡΠΎΡΡΡΡΠΊΡΡΡΠ° Ρ ΡΠ°Π·Π°ΠΌΠΈ, ΠΊΠΎΡΠΎΡΡΠ΅ ΡΠΎΠ΄Π΅ΡΠΆΠ°Ρ TiAlβ, TiAlβ ΠΈ AlβOβ
Developments in Corrosion Protection
One of the first thing that comes to your mind after hearing the term βcorrosionβ is corrosion of a metal. Corrosion is a basically harmful phenomenon, but it can be useful in some cases. For instance, environmentβs pollution with corrosion products and damage to the performance of a system are among its harmful effects, whereas electric energy generation in a battery and cathodic protection of many structures are among its advantages. However, these advantages are almost nothing as compared to the costs and effects imposed by its detrimental influences. The enormous costs of this phenomenon can be better understand through studying the published statistics on direct and indirect corrosion damages on economy of governments. The direct cost of corrosion is near 3 % of the gross domestic product (GDP) of USA. Considering this huge cost, it is necessary to develop and expand the corrosion science and its protection technologies
Duplex Surface Treatment of Pre-Electroplating and Pulsed Nanocrystalline Plasma Electrolytic Carbonitriding of Mild Steel
Effect of electrolyte temperature on the nano-carbonitride layer fabricated by surface nanocrystallization and plasma treatment on a Ξ³-TiAl alloy
EFFECT OF PULSE DUTY CYCLE ON PROPERTIES OF HARD NANOCRYSTALLINE SURFACE FABRICATED BY DUPLEX TREATMENTS
Up to fourth moment distribution of carbide nanocrystallites produced by duplex treatments of surface nanocrystallization and pulsed plasma electrolytic carbonitriding on AISI 1010 mild steel was investigated by the means of figure analysis with high precision. Skewness and kurtosis study of the Gaussian distribution have been studied and the effect of duty cycle of pulsed current has been determined. The usage of lower duty cycles of pulsed current is more suitable for achieving lower sizes of carbide nanocrystallites. Surface roughness of treated samples was measured and it has been observed that there is an optimum level of duty cycle of pulsed current for surface roughness increasing (difference between two measured data).Duty cycle of pulsed current, nanostructures, plasma electrolytic carbonitriding, kurtosis, skewness
Study of Pulsed Bipolar Nanocrystalline Plasma Electrolytic Carburizing on Nanostructure and Friction Coefficient of Compound Layer
Corrosion properties of electrodeposited nanocrystalline and amorphous patterned Ni-W alloy
Nickel-tungsten with satisfactory corrosion properties is a promising alloy to replace hard chromium. Relatively high adhesion between copper substrate and electrodeposited Ni-W alloy results in patterned morphology due to crack formation. In this work, corrosion resistance of patterned Ni-W alloys comprising 0-26 at.%.W were studied by potentiodynamic polarization and EIS in a medium containing Cl-. It is shown that corrosion resistance of single phase Ni-W is superior to amorphous and dual phase coated layers. It is also found that crack density is the dominant affecting factor on corrosion resistance of amorphous Ni-W alloys. (C) 2008 Elsevier Ltd. All rights reserved
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