The 93 W and Mo1 refractory metals were bonded with different Cu_(1-x)Ni_(x) coating interlayers of various Ni content using plasma-activated sintering at 700℃.The effects of the Ni content in the Cu_(1-x)Ni_(x) coat...The 93 W and Mo1 refractory metals were bonded with different Cu_(1-x)Ni_(x) coating interlayers of various Ni content using plasma-activated sintering at 700℃.The effects of the Ni content in the Cu_(1-x)Ni_(x) coating interlayer on the interfacial microstructure evolution and mechanical properties of the W/Mo joints were studied.The maximum average shear strength of the W/Mo joint was 316.5 MPa when the Ni content of the Cu_(1-x)Ni_(x) coating interlayer was 25%.When the Ni content of the Cu_(1-x)Ni_(x) coating interlayer was below 50%,the atomic diffusion at the W/Mo joint interface was adequate without the formation of intermetallic compounds,as demonstrated by the High Resolution Transmission Electron Microscope analyses of the joints.The presence of Ni in Cu_(1-x)Ni_(x) promoted diffusion bonding at the interface,which contributed to the high mechanical properties of the W/Mo joint.With an increase in the Ni content of the Cu_(1-x)Ni_(x) coating interlayer,the Mo Ni intermetallic compound(IMC)nucleated and grew at the Cu1-xNix coating/Mo1 interface.When the Ni content of the Cu_(1-x)Ni_(x) coating interlayer was above 50%,the generation of a brittle Mo Ni IMC weakened the shear strength of the W/Mo joint dramatically.展开更多
采用热力学和动力学方法研究了轴承钢GCr15凝固过程中溶质元素偏析、钛夹杂析出规律及影响钛夹杂长大的因素。研究表明:1)GCr15钢在凝固过程中Ti(C_(x)N_(1-x))先于TiN在凝固前沿的固液两相区析出,降低钢液初始Ti、N含量均能推迟Ti(C_(x...采用热力学和动力学方法研究了轴承钢GCr15凝固过程中溶质元素偏析、钛夹杂析出规律及影响钛夹杂长大的因素。研究表明:1)GCr15钢在凝固过程中Ti(C_(x)N_(1-x))先于TiN在凝固前沿的固液两相区析出,降低钢液初始Ti、N含量均能推迟Ti(C_(x)N_(1-x))在凝固前沿的析出。Ti(C_(x)N_(1-x))夹杂中的x值随w(Ti)_(0)下降而下降,但随w(N)_(0)下降而升高。2)凝固冷却速率对GCr15钢中Ti、N元素的凝固偏析影响不大,但对钛夹杂的长大影响显著。随着钢液初始Ti、N含量下降,钛夹杂凝固析出推迟,尺寸变小。采用70 t EAF→EBT→LF→RH→IC(模铸)工艺生产轴承钢GCr15大钢锭,从30 t GCr15钢锭经热锻/轧成的Ф75 mm圆棒上取样,w(T.O)、w(Ti)和w(N)分别为0.0007%、0.0010%、0.0019%。光学显微镜下检测到的钛夹杂是呈土红色的碳氮化钛夹杂;扫描电镜下观察到钢中钛夹杂形状不规则,钛夹杂最大尺寸17.4μm,平均尺寸为9.2μm,这与大吨位模铸锭冷却速率小有关。对大钢锭模铸而言,严格控制各工序钢水增Ti量和增N量,降低钢液中Ti、N含量,推迟钛夹杂在凝固过程中的析出是控制盾构机主轴承圆柱滚子用轴承钢GCr15产品钛夹杂尺寸的有效措施。展开更多
Solar photocatalysis,as a method of green energy production and sustainable technology,has been regarded as one of the most effective strategies to resolve environmental issues and the current energy crisis.In this wo...Solar photocatalysis,as a method of green energy production and sustainable technology,has been regarded as one of the most effective strategies to resolve environmental issues and the current energy crisis.In this work,intimate contact hollow Ni_(x)Co_(1-x)S polyhedron/g-C3N4 nanosheet composites were prepared in-situ through a facile one-step hydrothermal method.The as-prepared Ni_(x)Co_(1-x)S/g-C_(3)N_(4) composites showed superior photocatalytic activity and high stability for H2 generation and methyl orange(MO)degradation under visible light irradiation.The optimized 4 wt.%Ni_(x)Co_(1-x)S/g-C_(3)N_(4) composite attained a maximum H2 evolution rate of 1420μmol g^–1 h^–1,which was about 157 times higher than that of pure g-C3N4.In addition,the Ni_(x)Co_(1-x)S/g-C_(3)N_(4) composite also exhibited greatly improved photocatalytic activity for dye degradation,which for MO was at 98.14%in 9 min.The outstanding photocatalytic performance was predominantly attributed to the unique architecture of hollow Ni_(x)Co_(1-x)S polyhedrons,which not only provided more active sites at the edges and surface as convenient charge transfer channels,but also promoted the separation and transport of electron-hole pairs.This work provides some novel ideas for the design and development of highly efficient noble metal-free cocatalyst/semiconductor systems for photocatalytic H2 generation and dye degradation.展开更多
基金the National Natural Science Foundation of China(Nos.51572208 and 51521001)the 111 Project(No.B13035)the Joint Fund(No.6141A02022255)。
文摘The 93 W and Mo1 refractory metals were bonded with different Cu_(1-x)Ni_(x) coating interlayers of various Ni content using plasma-activated sintering at 700℃.The effects of the Ni content in the Cu_(1-x)Ni_(x) coating interlayer on the interfacial microstructure evolution and mechanical properties of the W/Mo joints were studied.The maximum average shear strength of the W/Mo joint was 316.5 MPa when the Ni content of the Cu_(1-x)Ni_(x) coating interlayer was 25%.When the Ni content of the Cu_(1-x)Ni_(x) coating interlayer was below 50%,the atomic diffusion at the W/Mo joint interface was adequate without the formation of intermetallic compounds,as demonstrated by the High Resolution Transmission Electron Microscope analyses of the joints.The presence of Ni in Cu_(1-x)Ni_(x) promoted diffusion bonding at the interface,which contributed to the high mechanical properties of the W/Mo joint.With an increase in the Ni content of the Cu_(1-x)Ni_(x) coating interlayer,the Mo Ni intermetallic compound(IMC)nucleated and grew at the Cu1-xNix coating/Mo1 interface.When the Ni content of the Cu_(1-x)Ni_(x) coating interlayer was above 50%,the generation of a brittle Mo Ni IMC weakened the shear strength of the W/Mo joint dramatically.
文摘采用热力学和动力学方法研究了轴承钢GCr15凝固过程中溶质元素偏析、钛夹杂析出规律及影响钛夹杂长大的因素。研究表明:1)GCr15钢在凝固过程中Ti(C_(x)N_(1-x))先于TiN在凝固前沿的固液两相区析出,降低钢液初始Ti、N含量均能推迟Ti(C_(x)N_(1-x))在凝固前沿的析出。Ti(C_(x)N_(1-x))夹杂中的x值随w(Ti)_(0)下降而下降,但随w(N)_(0)下降而升高。2)凝固冷却速率对GCr15钢中Ti、N元素的凝固偏析影响不大,但对钛夹杂的长大影响显著。随着钢液初始Ti、N含量下降,钛夹杂凝固析出推迟,尺寸变小。采用70 t EAF→EBT→LF→RH→IC(模铸)工艺生产轴承钢GCr15大钢锭,从30 t GCr15钢锭经热锻/轧成的Ф75 mm圆棒上取样,w(T.O)、w(Ti)和w(N)分别为0.0007%、0.0010%、0.0019%。光学显微镜下检测到的钛夹杂是呈土红色的碳氮化钛夹杂;扫描电镜下观察到钢中钛夹杂形状不规则,钛夹杂最大尺寸17.4μm,平均尺寸为9.2μm,这与大吨位模铸锭冷却速率小有关。对大钢锭模铸而言,严格控制各工序钢水增Ti量和增N量,降低钢液中Ti、N含量,推迟钛夹杂在凝固过程中的析出是控制盾构机主轴承圆柱滚子用轴承钢GCr15产品钛夹杂尺寸的有效措施。
基金financially supported by the National Natural Science Foundation of China(No.21801091)the Science Technology Development Planning of Jilin Province(No.20190103117JH)the Education Department Project of Jilin Province(Nos.JJKH20200242KJ and JJKH20190827KJ)。
文摘Solar photocatalysis,as a method of green energy production and sustainable technology,has been regarded as one of the most effective strategies to resolve environmental issues and the current energy crisis.In this work,intimate contact hollow Ni_(x)Co_(1-x)S polyhedron/g-C3N4 nanosheet composites were prepared in-situ through a facile one-step hydrothermal method.The as-prepared Ni_(x)Co_(1-x)S/g-C_(3)N_(4) composites showed superior photocatalytic activity and high stability for H2 generation and methyl orange(MO)degradation under visible light irradiation.The optimized 4 wt.%Ni_(x)Co_(1-x)S/g-C_(3)N_(4) composite attained a maximum H2 evolution rate of 1420μmol g^–1 h^–1,which was about 157 times higher than that of pure g-C3N4.In addition,the Ni_(x)Co_(1-x)S/g-C_(3)N_(4) composite also exhibited greatly improved photocatalytic activity for dye degradation,which for MO was at 98.14%in 9 min.The outstanding photocatalytic performance was predominantly attributed to the unique architecture of hollow Ni_(x)Co_(1-x)S polyhedrons,which not only provided more active sites at the edges and surface as convenient charge transfer channels,but also promoted the separation and transport of electron-hole pairs.This work provides some novel ideas for the design and development of highly efficient noble metal-free cocatalyst/semiconductor systems for photocatalytic H2 generation and dye degradation.
