A new molybdenum oxide phase which exists in bomb combustion products of Mo was found. It has been determined that this phase is a transformed MoO_3 of triclinic system.One set of its lattice parameters was also deter...A new molybdenum oxide phase which exists in bomb combustion products of Mo was found. It has been determined that this phase is a transformed MoO_3 of triclinic system.One set of its lattice parameters was also determined from the X-ray diffraction data as α=0.4049± 0.0001 nm,b=0.5079±0.0003 nm,c=1.4339±0.0009 nm,α=115.16±0.08°,β=90.69± 0.14°,γ=105.58±0.05° and unit cell volume=0.2544 nm^3.展开更多
The forming process of silicide coatings on pure Mo and Mo-base alloys, obtained by the gas- phase deposition method. has been studied by examining the microstructure of coatings and the relationship between coating t...The forming process of silicide coatings on pure Mo and Mo-base alloys, obtained by the gas- phase deposition method. has been studied by examining the microstructure of coatings and the relationship between coating thickness and process parameters. It was shown that the growth of coatings was diffusion-controlled, the diffusion of silicon to be coated into Mo or Mo-base alloys was mainly responsible for the formation of silicide. The relationship between initial silicide thickness and oxidation resistance was also investigated, and the equation of service life of the coatings at high temperature in air is presented.展开更多
The corrosion behavior of Ni–20Cr–18 W–1Mo superalloy in supercritical water 500 °C/25 MPa for 200 h is investigated using gravimetry, SEM/EDS, XPS, and TEM. The oxide films show a layered structure with Ni ri...The corrosion behavior of Ni–20Cr–18 W–1Mo superalloy in supercritical water 500 °C/25 MPa for 200 h is investigated using gravimetry, SEM/EDS, XPS, and TEM. The oxide films show a layered structure with Ni rich in the outer layer, and Cr rich in the inner layer, consisting of an outer Ni（OH）2and NiO layer, including some Cr（OH）3, and an inner Cr2O3, Ni Cr2O4, and WO3 layer. Mo elements are not oxidized. The oxide films grow via a mixed mechanism,namely metal dissolution/oxide precipitation mechanism and solid-state growth mechanism. The effects of secondary and primary carbides on the weight-gain trend and oxide formation are discussed.展开更多
文摘A new molybdenum oxide phase which exists in bomb combustion products of Mo was found. It has been determined that this phase is a transformed MoO_3 of triclinic system.One set of its lattice parameters was also determined from the X-ray diffraction data as α=0.4049± 0.0001 nm,b=0.5079±0.0003 nm,c=1.4339±0.0009 nm,α=115.16±0.08°,β=90.69± 0.14°,γ=105.58±0.05° and unit cell volume=0.2544 nm^3.
文摘The forming process of silicide coatings on pure Mo and Mo-base alloys, obtained by the gas- phase deposition method. has been studied by examining the microstructure of coatings and the relationship between coating thickness and process parameters. It was shown that the growth of coatings was diffusion-controlled, the diffusion of silicon to be coated into Mo or Mo-base alloys was mainly responsible for the formation of silicide. The relationship between initial silicide thickness and oxidation resistance was also investigated, and the equation of service life of the coatings at high temperature in air is presented.
基金financial support from the project supported by Research Fund of the State Key Laboratory of Solidification Processing, China (No. 62-TP-2011)111 project (No. B08040)
文摘The corrosion behavior of Ni–20Cr–18 W–1Mo superalloy in supercritical water 500 °C/25 MPa for 200 h is investigated using gravimetry, SEM/EDS, XPS, and TEM. The oxide films show a layered structure with Ni rich in the outer layer, and Cr rich in the inner layer, consisting of an outer Ni（OH）2and NiO layer, including some Cr（OH）3, and an inner Cr2O3, Ni Cr2O4, and WO3 layer. Mo elements are not oxidized. The oxide films grow via a mixed mechanism,namely metal dissolution/oxide precipitation mechanism and solid-state growth mechanism. The effects of secondary and primary carbides on the weight-gain trend and oxide formation are discussed.
