新型二元贵金属族氮化物在硬度和电学方面表现出优异的性能,被视为一种潜在的超硬功能材料.但由于其难以达到的高温高压合成条件,使得人们很难对其晶体结构、热力学规律和物化性质等方面进行更为深入的研究.因此,探寻一种在较低温压条...新型二元贵金属族氮化物在硬度和电学方面表现出优异的性能,被视为一种潜在的超硬功能材料.但由于其难以达到的高温高压合成条件,使得人们很难对其晶体结构、热力学规律和物化性质等方面进行更为深入的研究.因此,探寻一种在较低温压条件下制备贵金属氮化物的途径成为材料制备领域的焦点.本研究从制备碳包覆贵金属钯(Pd)超细纳米颗粒前驱体为出发点,采用直流电弧法与激光加温金刚石对顶砧相结合的方法,在7 G Pa压力和800 K温度的条件下成功制备氮化钯(PdN 2)纳米颗粒,这一合成条件较之前传统方法大幅降低,对其工业化批量生产的成本降低具有重要意义.本研究开创性的将纳米与高温高压相结合,首次制备了贵金属氮化物纳米级材料,为此类氮化物的合成提供了新途径,为其他潜在超硬材料的制备提供了新思路.展开更多
For laser assisted machining,shape of preheating laser heat source is changed irregularly because of complexity of material shape.So,the preheating temperature should be controlled by adjusting the feed rate or the la...For laser assisted machining,shape of preheating laser heat source is changed irregularly because of complexity of material shape.So,the preheating temperature should be controlled by adjusting the feed rate or the laser power.Thermal analyses of the laser assisted machining process for inclination planes were performed.By analyzing the obtained temperature profile,a proper feed rate control method was proposed according to the inclination angles.In addition,the temperature distribution of the cross section after feed rate control was predicted.The correlation equation between inclination angles and adjusted proper feed rate was proposed.The results of this analysis can be used to predict the preheating effect on workpiece and can be applied as a preheating temperature control method in laser assisted machining processes.展开更多
文摘新型二元贵金属族氮化物在硬度和电学方面表现出优异的性能,被视为一种潜在的超硬功能材料.但由于其难以达到的高温高压合成条件,使得人们很难对其晶体结构、热力学规律和物化性质等方面进行更为深入的研究.因此,探寻一种在较低温压条件下制备贵金属氮化物的途径成为材料制备领域的焦点.本研究从制备碳包覆贵金属钯(Pd)超细纳米颗粒前驱体为出发点,采用直流电弧法与激光加温金刚石对顶砧相结合的方法,在7 G Pa压力和800 K温度的条件下成功制备氮化钯(PdN 2)纳米颗粒,这一合成条件较之前传统方法大幅降低,对其工业化批量生产的成本降低具有重要意义.本研究开创性的将纳米与高温高压相结合,首次制备了贵金属氮化物纳米级材料,为此类氮化物的合成提供了新途径,为其他潜在超硬材料的制备提供了新思路.
基金Project(2011-0017407)supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MEST)
文摘For laser assisted machining,shape of preheating laser heat source is changed irregularly because of complexity of material shape.So,the preheating temperature should be controlled by adjusting the feed rate or the laser power.Thermal analyses of the laser assisted machining process for inclination planes were performed.By analyzing the obtained temperature profile,a proper feed rate control method was proposed according to the inclination angles.In addition,the temperature distribution of the cross section after feed rate control was predicted.The correlation equation between inclination angles and adjusted proper feed rate was proposed.The results of this analysis can be used to predict the preheating effect on workpiece and can be applied as a preheating temperature control method in laser assisted machining processes.
