Pub Date : 2023-01-01DOI: 10.4236/msa.2023.1410031
Rongrong Luo, Pengyuan Li, Teng Zhang, Tengfei Yan, Min Dan
Fasteners of 718 alloys are used to set up connection between each support and other components for ITER system, metal-based Ag solid lubricant coating is widely used as an anti-seizure lubricant coating due to its strong low-temperature shear resistance. But the poor adhesion to the steel surfaces has been a critical restriction for applying the silver coatings to the practical machine elements. In this work, an 8-μm silver self-lubricating coating was deposited on the surface of 718 alloy by the method of magnetron sputtering. The coating was uniform, dense and consistent. The wear mechanism was investigated by analyzing the friction and wear properties of the coating. Stress is one of the important impacts on the friction coefficient, the results showed that it first increased and then decreased with the increase of pressure at room temperature and under vacuum. Temperature exerted an effect on the silver self-lubricating coating. A study was conducted under vacuum on the friction and wear performance of the coating at 300 K, 225 K, 155 K, and 77 K, respectively. The results showed that the wear mechanism and wear state varied under various low-temperature conditions, with the severity of wear reaching the maximum only at 225 K. Through the same silver coating process, the washer of superbolt was improved by silver coating treatment.
{"title":"Exploring the Friction and Wear Properties of Silver Coatings on 718 Alloy","authors":"Rongrong Luo, Pengyuan Li, Teng Zhang, Tengfei Yan, Min Dan","doi":"10.4236/msa.2023.1410031","DOIUrl":"https://doi.org/10.4236/msa.2023.1410031","url":null,"abstract":"Fasteners of 718 alloys are used to set up connection between each support and other components for ITER system, metal-based Ag solid lubricant coating is widely used as an anti-seizure lubricant coating due to its strong low-temperature shear resistance. But the poor adhesion to the steel surfaces has been a critical restriction for applying the silver coatings to the practical machine elements. In this work, an 8-μm silver self-lubricating coating was deposited on the surface of 718 alloy by the method of magnetron sputtering. The coating was uniform, dense and consistent. The wear mechanism was investigated by analyzing the friction and wear properties of the coating. Stress is one of the important impacts on the friction coefficient, the results showed that it first increased and then decreased with the increase of pressure at room temperature and under vacuum. Temperature exerted an effect on the silver self-lubricating coating. A study was conducted under vacuum on the friction and wear performance of the coating at 300 K, 225 K, 155 K, and 77 K, respectively. The results showed that the wear mechanism and wear state varied under various low-temperature conditions, with the severity of wear reaching the maximum only at 225 K. Through the same silver coating process, the washer of superbolt was improved by silver coating treatment.","PeriodicalId":18454,"journal":{"name":"Materials Sciences and Applications","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136208398","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Reyna Anahí Falcón-Castrejón, Jose Luis Román-Zubillaga, Rene Guardián-Tapia, Lazaro Falcón-Franco, Isaí Rosales-Cadena
In this investigation, the addition of several amounts of metal oxide particles (CuO2) in Al matrix is carried out due to the need to improve the mechanical properties such as the ductility of aluminum for applications in the electrical sector. Samples were obtained by means of a stirring casting process. From the results of the microstructural characterization, it was observed that the metallic oxides induce the modification of the dendritic structure and grain refinement. X-ray diffraction characterization mainly shows the formation of Al2CuO4, Al2O3 and CuO compounds. Mechanical properties showed that the different thermal treatments resulted in an improved hardness, from 30 kg/mm2 for the un-reinforced sample to 90 kg/mm2 for reinforced samples. The addition of metallic oxides in the Al matrix produces an improved electrical conductivity specifically in sample with 0.50 g of CuO2 additions.
在本研究中，由于需要改善机械性能，如铝在电气领域应用的延展性，在铝基体中添加了一定量的金属氧化物颗粒(CuO2)。样品是通过搅拌铸造工艺获得的。显微组织表征结果表明，金属氧化物诱导了枝晶组织的改变和晶粒的细化。x射线衍射表征主要表现为Al2CuO4、Al2O3和CuO化合物的形成。力学性能表明，不同的热处理导致硬度的提高，从未增强样品的30 kg/mm2到增强样品的90 kg/mm2。在Al基体中添加金属氧化物，特别是在添加0.50 g CuO2的样品中，电导率得到改善。
{"title":"Synthesis and Characterization of Aluminum Alloys with Metal Oxides (CuO<sub>2</sub>) Additions as Reinforcement","authors":"Reyna Anahí Falcón-Castrejón, Jose Luis Román-Zubillaga, Rene Guardián-Tapia, Lazaro Falcón-Franco, Isaí Rosales-Cadena","doi":"10.4236/msa.2023.148027","DOIUrl":"https://doi.org/10.4236/msa.2023.148027","url":null,"abstract":"In this investigation, the addition of several amounts of metal oxide particles (CuO2) in Al matrix is carried out due to the need to improve the mechanical properties such as the ductility of aluminum for applications in the electrical sector. Samples were obtained by means of a stirring casting process. From the results of the microstructural characterization, it was observed that the metallic oxides induce the modification of the dendritic structure and grain refinement. X-ray diffraction characterization mainly shows the formation of Al2CuO4, Al2O3 and CuO compounds. Mechanical properties showed that the different thermal treatments resulted in an improved hardness, from 30 kg/mm2 for the un-reinforced sample to 90 kg/mm2 for reinforced samples. The addition of metallic oxides in the Al matrix produces an improved electrical conductivity specifically in sample with 0.50 g of CuO2 additions.","PeriodicalId":18454,"journal":{"name":"Materials Sciences and Applications","volume":"255 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136160070","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The antibacterial activity of copper is well-known from an ancient civilization, however, its biocidal mechanism has not been necessarily elucidated. Notwithstanding up to now, mainly 4 processes have been proposed. Among them, it is cleared that 4 kinds of reactive oxygen species (ROS): hydroxyl radical ·OH, hydrogen per oxide H2O2, superoxide anion ·O-2 and singlet oxygen 1O2, play an important role for contact-killing of bacteria, viruses and fungi. In this paper, generation of ROS on the surfaces of copper plates heated from room temperature to 673 K for 4.2 × 102 s in air, was investigated using the chemiluminescence. ROS have been evaluated by selecting the most suitable scavengers, such as 2-propanol for ·OH, sodium pyruvate for H2O2, nitro blue tetrazolium for ·O-2, and sodium azide NaN3 for 1O2. At the same time the outermost surface of copper, on which thin film of cuprous oxide Cu2O was first formed and then cupric oxide CuO was laminated on Cu2O, was examined by thin-film XRD and TEM analysis to estimate the amounts and kinds of copper oxides. It was found that the most amounts of ROS were obtained for the 573 K-heated Cu plate and they were composed of ·OH, H2O2, and ·O-2.
{"title":"Evaluation of Reactive Oxygen Species (ROS) Generated on the Surface of Copper Using Chemiluminesence","authors":"Ken Hirota, Hiroya Tanaka, Taika Maeda, Kazuhiko Tsukagoshi, Hiroshi Kawakami, Takashi Ozawa, Masahiko Wada","doi":"10.4236/msa.2023.1410032","DOIUrl":"https://doi.org/10.4236/msa.2023.1410032","url":null,"abstract":"The antibacterial activity of copper is well-known from an ancient civilization, however, its biocidal mechanism has not been necessarily elucidated. Notwithstanding up to now, mainly 4 processes have been proposed. Among them, it is cleared that 4 kinds of reactive oxygen species (ROS): hydroxyl radical ·OH, hydrogen per oxide H2O2, superoxide anion ·O-2 and singlet oxygen 1O2, play an important role for contact-killing of bacteria, viruses and fungi. In this paper, generation of ROS on the surfaces of copper plates heated from room temperature to 673 K for 4.2 × 102 s in air, was investigated using the chemiluminescence. ROS have been evaluated by selecting the most suitable scavengers, such as 2-propanol for ·OH, sodium pyruvate for H2O2, nitro blue tetrazolium for ·O-2, and sodium azide NaN3 for 1O2. At the same time the outermost surface of copper, on which thin film of cuprous oxide Cu2O was first formed and then cupric oxide CuO was laminated on Cu2O, was examined by thin-film XRD and TEM analysis to estimate the amounts and kinds of copper oxides. It was found that the most amounts of ROS were obtained for the 573 K-heated Cu plate and they were composed of ·OH, H2O2, and ·O-2.","PeriodicalId":18454,"journal":{"name":"Materials Sciences and Applications","volume":"135 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136208414","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.4236/msa.2023.1411033
Francesco Rosalbino, Daniele Macciò, Giorgio Scavino
The electrochemical corrosion behaviour of three Zr-Ag alloys (Zr-1Ag, Zr-3Ag and Zr-5Ag) was investigated. Open circuit potential, linear potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques were employed in aerated artificial saliva (pH = 4.0) at 37°C. Silver alloying additions are found to be effective in enhancing the corrosion resistance of zirconium in artificial saliva environment. In fact, Zr-Ag alloys exhibit higher open circuit potentials, larger breakdown potentials and higher impedance values as compared to cp Zr. This behaviour can be ascribed to the formation of a thicker and more stable passive film with increasing compactness, able to provide better protection against the corrosion attack.
{"title":"Corrosion Behaviour of Zr-Ag Alloys for Dental Implant Application","authors":"Francesco Rosalbino, Daniele Macciò, Giorgio Scavino","doi":"10.4236/msa.2023.1411033","DOIUrl":"https://doi.org/10.4236/msa.2023.1411033","url":null,"abstract":"The electrochemical corrosion behaviour of three Zr-Ag alloys (Zr-1Ag, Zr-3Ag and Zr-5Ag) was investigated. Open circuit potential, linear potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques were employed in aerated artificial saliva (pH = 4.0) at 37°C. Silver alloying additions are found to be effective in enhancing the corrosion resistance of zirconium in artificial saliva environment. In fact, Zr-Ag alloys exhibit higher open circuit potentials, larger breakdown potentials and higher impedance values as compared to cp Zr. This behaviour can be ascribed to the formation of a thicker and more stable passive film with increasing compactness, able to provide better protection against the corrosion attack.","PeriodicalId":18454,"journal":{"name":"Materials Sciences and Applications","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135659079","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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