A γ-TiAl alloy with nominal composition of Ti-47%Al（molar fraction） was directionally solidified in an alumina mould with an Y2O3 protective coating.The effects of processing parameters（melting temperature and int...A γ-TiAl alloy with nominal composition of Ti-47%Al（molar fraction） was directionally solidified in an alumina mould with an Y2O3 protective coating.The effects of processing parameters（melting temperature and interaction time） on the metal-coating interface,microstructure and chemical composition of the alloy were evaluated.The result shows that the Y2O3 protective coating exhibits an effective barrier capability to avoid direct contact between the mould base material and the TiAl melt,although the Y2O3 coating is found to suffer some erosion and be slightly dissolved by the molten TiAl due to the coating-metal interactions.The directionally solidified alloys were contaminated with Y and O,and Y2O3 inclusions were dispersed in the metal matrix.The reason for this metal contamination is the Y2O3 coating dissolution by the TiAl melt.One mode of the interaction between Y2O3 and the TiAl melt is dissolution of yttrium and atomic oxygen in the melt by reaction Y2O3（s）=2Y（in TiAl melt）＋3O（in TiAl melt）.Both the extent of alloy contamination and the volume fractions of Y2O3 inclusions depend on the melting temperature and the interaction time.展开更多
Microbiologically induced corrosion of concrete （MICC） and its protective coatings has a high eco-nomic impact on sewer maintenance and rehabilitation. A better understanding of the micro-organisms and the bio- geni...Microbiologically induced corrosion of concrete （MICC） and its protective coatings has a high eco-nomic impact on sewer maintenance and rehabilitation. A better understanding of the micro-organisms and the bio- genie acids that are generated in the sewer is essential in controlling the corrosion of concrete pipes and protective coatings. The role of succession of micro-organisms growth in the corrosion of concrete and protective coatings was evaluated in this study. Examination of various sewer pipe materials exhibiting various extents of degradation, including concrete, cement based and epoxy based coating revealed the presence of both organic and biogenic sulphuric acids. This reflects the activity of fungi and the thiobacilli strains. Organism growth and metabolism were strongly related to the substrate pH. Fungi were found to grow and metabolise organic acids at pH from 2.0-8.0. Whilst the thiobacilli strains grew and generated sulohuric acids at oH below 3.0. The successive growth of the organisms provides an impgrtant bearing in deyeloping improved strateegies.to better manage sewers.展开更多
A simple fabrication method of microwave protective mirror is presented. Manufacturing principles, techniques and influence of the materials and film system parameters on the optical characteristics are discussed. Mea...A simple fabrication method of microwave protective mirror is presented. Manufacturing principles, techniques and influence of the materials and film system parameters on the optical characteristics are discussed. Measured spectral transmittance curves of microwave protective mirror are given.展开更多
The study analysed the behaviour of titanium dioxide （TiO2） in polyethylene teraphthalate （PET） polymer coatings on ECCS steel plates. The work determined the thermal source affecting rutile distribution in the PE...The study analysed the behaviour of titanium dioxide （TiO2） in polyethylene teraphthalate （PET） polymer coatings on ECCS steel plates. The work determined the thermal source affecting rutile distribution in the PET coating： It originated in the manufacturing processes and thermomechanical treatments of the composite, and affected PET adherence on the steel. These results were contrasted with the behaviour of a non-heated coating to determine the conditions under which the ruffle exhibits changes on the PET coating. Measurements at cross-section and parallel intervals from the surface to the metal interface were made by FTIR-ATR and Raman vibrational spectroscopy techniques to characterise the rutile distribution in the PET thickness.展开更多
文摘A γ-TiAl alloy with nominal composition of Ti-47%Al（molar fraction） was directionally solidified in an alumina mould with an Y2O3 protective coating.The effects of processing parameters（melting temperature and interaction time） on the metal-coating interface,microstructure and chemical composition of the alloy were evaluated.The result shows that the Y2O3 protective coating exhibits an effective barrier capability to avoid direct contact between the mould base material and the TiAl melt,although the Y2O3 coating is found to suffer some erosion and be slightly dissolved by the molten TiAl due to the coating-metal interactions.The directionally solidified alloys were contaminated with Y and O,and Y2O3 inclusions were dispersed in the metal matrix.The reason for this metal contamination is the Y2O3 coating dissolution by the TiAl melt.One mode of the interaction between Y2O3 and the TiAl melt is dissolution of yttrium and atomic oxygen in the melt by reaction Y2O3（s）=2Y（in TiAl melt）＋3O（in TiAl melt）.Both the extent of alloy contamination and the volume fractions of Y2O3 inclusions depend on the melting temperature and the interaction time.
文摘Microbiologically induced corrosion of concrete （MICC） and its protective coatings has a high eco-nomic impact on sewer maintenance and rehabilitation. A better understanding of the micro-organisms and the bio- genie acids that are generated in the sewer is essential in controlling the corrosion of concrete pipes and protective coatings. The role of succession of micro-organisms growth in the corrosion of concrete and protective coatings was evaluated in this study. Examination of various sewer pipe materials exhibiting various extents of degradation, including concrete, cement based and epoxy based coating revealed the presence of both organic and biogenic sulphuric acids. This reflects the activity of fungi and the thiobacilli strains. Organism growth and metabolism were strongly related to the substrate pH. Fungi were found to grow and metabolise organic acids at pH from 2.0-8.0. Whilst the thiobacilli strains grew and generated sulohuric acids at oH below 3.0. The successive growth of the organisms provides an impgrtant bearing in deyeloping improved strateegies.to better manage sewers.
文摘A simple fabrication method of microwave protective mirror is presented. Manufacturing principles, techniques and influence of the materials and film system parameters on the optical characteristics are discussed. Measured spectral transmittance curves of microwave protective mirror are given.
文摘The study analysed the behaviour of titanium dioxide （TiO2） in polyethylene teraphthalate （PET） polymer coatings on ECCS steel plates. The work determined the thermal source affecting rutile distribution in the PET coating： It originated in the manufacturing processes and thermomechanical treatments of the composite, and affected PET adherence on the steel. These results were contrasted with the behaviour of a non-heated coating to determine the conditions under which the ruffle exhibits changes on the PET coating. Measurements at cross-section and parallel intervals from the surface to the metal interface were made by FTIR-ATR and Raman vibrational spectroscopy techniques to characterise the rutile distribution in the PET thickness.
