Materials
·
2020
·Vol. 13
·期 12
·2719
·
IF 3.057
Yan Jiang,Junfeng Yang,Zhuoming Xie,Qianfeng Fang
The biggest obstacle for the application of tungsten as the target materials in the spallation neutron source is its serious corrosion in the coolant of flowing water. For this reason, W–Cr–C clad tungsten was developed by tungsten carburizing in a spark plasma sintering device, with superior corrosion resistance in the static immersion and electrochemical corrosion test. This work focused on its erosion and corrosion performance in a flowing water system, based upon test parameters simulated under the service conditions. W–Cr–C clad tungsten showed superior corrosion resistance to that of bare tungsten due to the corrosion form changing from the intergranular corrosion of bare tungsten to pitting corrosion of W–Cr–C coating. The corrosion rate of tungsten was as high as tenfold that of the coated sample at 20 °C, and at most fourfold at 60 °C after testing for 360 h. Effects of water velocity and temperature on pitting and intergranular corrosion were investigated in detail and their corresponding corrosion mechanisms were analyzed and discussed.Keywords:tungsten;W–Cr–C coating;carburization;intergranular corrosion;pitting corrosion
研究领域:
材料科学
·
腐蚀与防护
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Metals
·
2022
·Vol. 12
·期 5
·871
·
IF 2.695
Cui Wang,Jianliang Zhang,Wen Chen,Xiaolei Li,Kexin Jiao,Zhenping Pang,Zhongyi Wang,Tongsheng Wang,Zhengjian Liu
The corrosion resistance to molten iron of four kinds of carbon bricks used in blast furnace hearth were investigated to elaborate the corrosion mechanism through the macroscopic and microscopic analysis of carbon bricks before and after reaction and thermodynamic analysis. The macroscopic analysis showed that brick A had the lowest degree of corrosion and highest uniformity at different heights, attributing to its moderate carbon content of 76.15%, main phases of C, Al2O3, SiC, and Al6Si2O13(mullite), and lower resistance to molten iron infiltration, etc. The microscopic analysis showed that all the carbon bricks had more and larger pores than the original carbon bricks. The phenomena of the iron beads adhering to carbon brick and iron infiltration were observed between the interface of carbon brick and molten iron. In addition, the obvious corrosion process was presented that the carbon matrix was broken and peeled off during the iron infiltration process. For the carbon brick being corroded, the dissolution of carbon was the predominant reaction. The higher the carbon solubility of the molten iron, the easier the corrosion on the carbon brick. Al2O3and SiC enhanced the corrosion resistance to molten iron of carbon bricks, and SiO2could react with carbon to form pores as channels for the penetration of molten iron and increase the corrosion on carbon bricks. A higher graphitization degree of carbon bricks was beneficial to lessen their corrosion degree. The corrosion on carbon bricks by molten iron could be attributed to three aspects: carburization, infiltration, and scouring of molten iron. The carburization process of molten iron was the main reaction process. The molten iron infiltration into the carbon bricks facilitated the dissolution of carbon and destroyed the structure and accelerated the corrosion of the carbon bricks. The scouring of molten iron subjected the iron–carbon interface to interaction forces, promoting the separation of the exfoliated fragmented carbon brick from the iron–carbon interface to facilitate a new round of corrosion process.Keywords:carbon brick;corrosion resistance to molten iron;carburization;iron infiltration
研究领域:
材料科学
·
冶金工程
✓ 已验证
产品关联
DOI
高影响因子
SURFACE & COATINGS TECHNOLOGY
·
2024
·
IF 5.3
Meiyu Zhao,Mengyi Tang,Hao Shi,Haiou Sun,Xiaoping Li,Huayi Yin,Dihua Wang
Salt-thermo-carburizing (STC) by simply soaking transition metals in molten CaCl 2 -CaC 2 is an effective method to prepare carbide coatings on metallic substrates. Herein, more efficient anodic carburizing (AC) is demonstrated in the same molten salt via electrochemical oxidation of C 2 2− , which greatly accelerating the growing rate of the carbide coating. Typically, TiC coating was successfully prepared on titanium anode coupled with a graphite cathode. The effect of current density, reaction temperature, and reaction time on the composition, morphology, and structure of the carbide coating was systematically investigated. The results demonstrate that anodic carburizing enables a dense, uniform TiC coating formation with a relatively high rate. The growing kinetics of TiC follows parabolic law for both of AC and STC process, but the rate constant of AC (17.61 μm h -0.5 ) is much higher than that of STC (5.17 μm h -0.5 ). It only takes ~0.7 h for the AC process to get a TiC coating with a thickness of 15 μm at 875 °C, but takes >8 h for the STC process. The applied anodic polarization improves the interfacial carbon potential gradient by promoting the C 2 2− oxidation, thereby accelerating the growth rate of TiC coatings.
研究领域:
材料科学
·
电化学工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2019
·
IF 3.45
Lin Wang,Yongshuai Xie,Dehua Ma,Luyi Zhu,Xinqiang Wang,Xiaotong Jin,Chonghe Xu,Ying Peng,Guanghui Zhang,Dong Xu
As a polycrystalline fiber, continuous zirconia (ZrO 2 ) fiber used at high temperatures will cause grain coarsening and strength degradation due to grain growth. In order to suppress the grain coarsening, zirconium carbide (ZrC) and carbon were introduced into ZrO 2 continuous fibers by pack carburizing , and ZrC/ZrO 2 composite fibers with a radial gradient were subsequently prepared. Due to the pinning effect of ZrC or carbon on the grain boundary, the movement of the grain boundary is limited. The composite fibers obtained in an argon atmosphere at 1400 °C exhibited fine grain, compact micromorphology, and a tensile strength of 784 MPa. The formation process of the composite fiber was accomplished by the interaction of external graphite carbon and internal residual carbon with ZrO 2 . This work provides a simple and economical method for preparing carbide composite fibers.
研究领域:
材料科学
·
高温材料
✓ 已验证
产品关联
DOI
高影响因子
SURFACE & COATINGS TECHNOLOGY
·
2023
·
IF 5.4
Meiyu Zhao,Yongsong Ma,Yu Zhang,Xianglin Liu,Haiou Sun,Renhe Liang,Huayi Yin,Dihua Wang
Titanium carbide (TiC) coating was prepared by in-situ carbonization of titanium using a novel salt-thermo-carburizing (STC) method in molten CaCl 2 -CaC 2 . The effect of the concentration of CaC 2 , the temperature of the melt and the reaction duration on the composition, structure and thickness of the carbide coating were systematically investigated. The optimized immersion bath was CaCl 2 –2 wt% CaC 2 at 900 °C. The thickness of the coating was increasing with the immersion time and it can reach 105 μm within 8 h. It was found that the growth kinetics of TiC coating follows a parabolic law in the temperature range of 850 to 900 °C, the obtained growth rate constants ( k ) is 1.43 × 10 −15 at 850 °C, 68.38 × 10 −15 at 875 °C, and 320.17 × 10 −15 m 2 /s at 900 °C, respectively. In addition, the microhardness of the TiC coating obtained at 850 °C and 8 h is over 740 HV, which is more than five times that of the Ti substrate. This work offers a universal and facile method to prepare metallic carbide coating on the respective metal substrate.
研究领域:
材料科学
·
表面工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Kejia Kang,Bo Yu,Guanyu Deng,Pei Wang,Jian Yin,Hongbo Zhang,Guoqiang Luo,Hao Song
Copper impregnated carbon/carbon composite (Cu-C/C composite) was fabricated for novel sliding collector material by weaving carbon fiber, heat treatment and Cu alloy impregnation. The effects of counterpart materials (Fe ball and Cu ball) on friction and wear behaviors were investigated and compared with the result of carbon contact strip used in high-speed railway. Morphology, chemical composition, phase and structure of wear surface and tribolayer were characterized to clarify tribological mechanisms. The results show that friction coefficient follows the order: Cu-C/C composite/Cu ball > carbon contact strip/Fe ball > Cu-C/C composite/Fe ball > carbon contact strip/Cu ball. The carbon crystalline of wear surface appears preferred orientation along the sliding orientation, which is benefit for boundary lubrication . When the counterpart material is Fe ball, Cu-C/C composite is superior to pure carbon strip in mechanical strength , electrical conductivity , wear resistance and friction performance.
研究领域:
材料科学
·
摩擦学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2025
·
IF 6.3
Tingting Lv,Tu Hu,Fang Tian
The conventional carbothermal reduction method for preparing titanium carbide (TiC) from titanium dioxide (TiO 2 ) suffers from high reaction temperature and long processing time, necessitating development of novel reduction processes to reduce energy consumption and improve efficiency. This study utilizing a composite reducing agent of C+H 2 for reducing TiO 2 enables the efficient synthesis of titanium carbide, combining the advantages of both carbon and hydrogen. Herein, we systematically compare titanium carbide synthesis in TiO 2 -C and TiO 2 -C-H₂ systems to elucidate the mechanism of hydrogen enhancement. Thermodynamic calculations compare the preparation processes of titanium carbide in two different systems and reveal the dual role of hydrogen: participation in the reduction reaction and lowering of the oxygen potential. Experimental results demonstrate that the introduction of hydrogen not only significantly increases the carburizing rate from 36.09% to 92.46%, promoting the formation of TiC x O 1-x as the dominant phase, but also doubles the CO content in the exhaust gas compared to the hydrogen-free system. Integrated theoretical-experimental analysis reveals the triple role of hydrogen in accelerating the TiO 2 →TiC x O 1-x transformation through: (1) synergistic reduction with both C and CO, (2) effective lowering oxygen potential of the system, which enhances the thermodynamic driving force to accelerate both the TiO 2 →Ti 2 O 3 reduction and subsequent carbide formation, and (3) increased pore volume generation within the titanium oxide matrix due to the superior diffusivity and reducing capability of hydrogen, thereby facilitating enhanced gas diffusion pathways. This study provides fundamental mechanistic insights into the hydrogen-enhanced carbothermal reduction process for efficient TiC synthesis from TiO₂.
研究领域:
材料科学
·
化学工程
·
无机化学
·
热力学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）