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- 摘要
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- 实验方案
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High Temperature Oxidation and Wear Resistance of In Situ Synthesized (Ti3Al?+?TiB)/Ti Composites by Laser Cladding
摘要： (Ti3Al + TiB)/Ti composites were prepared on Ti6Al4V by laser cladding. The microstructures of the coatings were analyzed; the high temperature wear and oxidation properties of the coatings were investigated and compared with Ti6Al4V. Ti3Al and TiB particles were in situ formed through the reaction between Ti and AlB2. The reinforcements exhibited some crystallographic orientation relationships with a-Ti matrix, and a semi-coherent interface (Ti3Al) or a coherent interface (TiB) was obtained. The weight gain of the coating under each combination of temperature and time condition was 20 to 30 pct of the value of Ti6Al4V under the same experimental parameters. A denser and well-bonded TiO2 + Al2O3 layer was formed, effectively hindering the oxygen diffusion compared with the TiO2 layer on Ti6Al4V. EBSD result showed that the Al2O3 mainly assembled into clusters and located close to the interface while the outer area of the oxidation layer was mainly TiO2. The friction coefficients and wear losses of the coatings were lower than those of the substrates at 300 °C to 750 °C. The oxidation was a crucial factor affecting the wear performance at high temperatures. The protective effect of the TiO2 + Al2O3 layer and the formation of transfer films on the worn surface contributed to the improved wear resistance of the coating.
关键词： TiB,Laser Cladding,Wear Resistance,Ti Composites,In Situ Synthesized,High Temperature Oxidation,Ti3Al
更新于2025-11-28 14:24:20
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Effect of laser shock processing on oxidation resistance of laser additive manufactured Ti6Al4V titanium alloy
摘要： The high-temperature oxidation resistance of laser additive manufactured (LAM) Ti6Al4V before and after laser shock processing (LSP) was investigated. The samples were oxidized at 400?800 °C for 1?50 h in air. The results revealed that the rate of weight gain of the Ti6Al4V fabricated through LAM decreased, and LSP had a positive effect on increasing the oxidation resistance. At an oxidation temperature of 700 °C, an aluminum-rich layer was observed in the cross-section before LSP. After LSP, the aluminum-rich layer changed to three layers. The aluminum-rich layer prevented the diffusion of oxygen, which improved the oxidation resistance of the Ti6Al4V.
关键词： Ti6Al4V titanium alloy,High-temperature oxidation resistance,Laser shock processing,Laser additive manufacturing
更新于2025-09-23 15:21:01
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High-rate deposition of silicon films in a magnetron discharge with liquid target
摘要： Silicon coatings have been deposited on substrates made of low-carbon and high-carbon steels and tungsten in a magnetron discharge with liquid target at substrate bias voltages ranging from +100 V to -600 V. The structure of obtained coatings was examined by a scanning electron microscopy. The strong influence of substrate bias voltage on the coating structure was observed. The corrosion resistance of coated steel samples was examined in concentrated sulphuric, hydrochloric and nitric acids and their solutions. The resistance of coated tungsten samples against high-temperature oxidation was examined by their exposure to O2 gas at a pressure of 0.2 Pa and a temperature of 1073 K. The coatings deposited under bias voltages of +100 V and -600 V had dense structures and showed the best protective properties among all deposited coatings.
关键词： high-temperature oxidation,silicon coatings,liquid target,corrosion resistance,magnetron discharge
更新于2025-09-10 09:29:36
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[IEEE 2018 2nd International Conference on Engineering Innovation (ICEI) - Bangkok (2018.7.5-2018.7.6)] 2018 2nd International Conference on Engineering Innovation (ICEI) - Schottky's Barrier Height of T91/Cr2O3 Heterojunction in Dry and Wet Conditions: Effects of WaterVapor Onto Accelerated High Temperature Oxidation
摘要： Increasing the operating temperature in thermal power plant will further accelerate the high temperature oxidation with the presence of water vapor. It is hypothesized that water vapor provides hydrogen that dissolves into the ferritic alloy susbstrate, hence altering their electronic state at the metal-semiconductor (oxide) interface. This study aims to quantitatively prove above postulation by comparing their Schottky’s Barrier Height (SBH) in dry and wet environment. The Schottky’s barrier was prepared by sputtering Cr2O3 onto the T91 boiler tube in high vacuum condition using RF power 150W for an hour. The T91/Cr2O3 junction was then connected with platinum wire for capacitance-voltage, C-V test at high temperature. The value of Vbi was used to calculate the SBH, which increase proportionately with built in voltage. It is clearly shown that the SBH value in wet condition is higher than that in dry condition by 10.3%. This is explained by the formation of space charge layer at metal/oxide interface due to dissolved hydrogen in metal, thus may change the transport property and accelerate the oxidation rate in water vapor.
关键词： T91 alloy,Cr2O3,Schottky’s barrier,High temperature oxidation
更新于2025-09-04 15:30:14