In order to improve the corrosion resistance of NdFeB,AlN/Al dual protective coatings were prepared by DC magnetron sputtering in a home-made industrial apparatus.The inner Al layer with an excellent toughness was dep...In order to improve the corrosion resistance of NdFeB,AlN/Al dual protective coatings were prepared by DC magnetron sputtering in a home-made industrial apparatus.The inner Al layer with an excellent toughness was deposited onto NdFeB substrate firstly.And then the outmost AlN layer with a higher hardness was prepared with the nitrogen/argon mixture gas of the nitrogen partial pressure at 50%of the total pressure of 0.5 Pa and depositing time of 30,50 and 70 min,respectively.The denser outmost AlN layer was formed on the inner Al crystal layer.There is an occurrence of the interfacial reaction and metallurgy bonding in the interface layer between the coatings and NdFeB substrate.It has been found that the thickness of outmost AlN layer has a significant impact on corrosion resistance.For 50 min to deposit outmost AlN layer,AlN/Al coated NdFeB has the best corrosion resistance.展开更多
通过热力学方法分析了 Al N生成反应进行的可能性 ,探讨了 Al N/ Al原位复合材料的金相组织 ,确定了增强相 Al N的存在及其尺寸大小。研究结果表明 :Al N增强相为纳米级尺寸 ,它均匀分布于共晶相中 ,基体α- Al相中没有Al N相。纳米增强...通过热力学方法分析了 Al N生成反应进行的可能性 ,探讨了 Al N/ Al原位复合材料的金相组织 ,确定了增强相 Al N的存在及其尺寸大小。研究结果表明 :Al N增强相为纳米级尺寸 ,它均匀分布于共晶相中 ,基体α- Al相中没有Al N相。纳米增强相 Al N对复合材料有细化晶粒强化及弥散强化作用。展开更多
The pressureless infiltration process to synthesize a silicon nitride composite was investigated. An Al-2wt%Mg alloy was infiltrated into silicon nitride preforms in the atmosphere of nitrogen. It is possible to infil...The pressureless infiltration process to synthesize a silicon nitride composite was investigated. An Al-2wt%Mg alloy was infiltrated into silicon nitride preforms in the atmosphere of nitrogen. It is possible to infiltrate the Al-2wt%Mg alloy in silicon nitride preforms, The growth of the composite with useful thickness was facilitated by the presence of magnesium powder at the interface and by flowing nitrogen. The microstructure of the Si3N4-Al composite has been characterized using scanning electron microscope. During the infiltration of Si3N4 preforms, Si3N4 reacted with aluminium to form silicon and AIN. The silicon produced during the growth consumed in the formation of MgSiAIO, MgSiAlN and Al3.27Si0.47 type phases. The growth of the composite was found to proceed in two ways, depending on the oxide content in the initial preforms, First, less oxide content preforms gave rise to MgAlSiO and MgAlSiN type phases after infiltration. Second, more oxide content preforms gave rise to AlN-Al2O3 solid solution phase （AlON）, The AlON phase was only present in the composite, containing 10% aluminium in the silicon nitride preforms before infiltration.展开更多
Recently, the study of nanocomposites has attracted much attention, but the powder isdifficult to be homogenized and nanoparticles are not well distributed when nanophase isintroduced into matrix via general mechanica...Recently, the study of nanocomposites has attracted much attention, but the powder isdifficult to be homogenized and nanoparticles are not well distributed when nanophase isintroduced into matrix via general mechanical mixing. The in situ formation of AlNsubmicron particles in Al<sub>2</sub>O<sub>3</sub> matrix has been explored to prepare AlN-Al<sub>2</sub>O<sub>3</sub> composite bymeans of reaction-bonding method.展开更多
基金Zhejiang Provincial Natural Science Foundation of China(Y4090178)Ningbo Natural Science Foundation of China(2011A610208)+1 种基金Advanced Coating and Film innovation team(2011B81001)Outstanding Talent Recruiting Program Dedicated to Academician Q.J.Xue"(2009A31004)from Ningbo municipal government
文摘In order to improve the corrosion resistance of NdFeB,AlN/Al dual protective coatings were prepared by DC magnetron sputtering in a home-made industrial apparatus.The inner Al layer with an excellent toughness was deposited onto NdFeB substrate firstly.And then the outmost AlN layer with a higher hardness was prepared with the nitrogen/argon mixture gas of the nitrogen partial pressure at 50%of the total pressure of 0.5 Pa and depositing time of 30,50 and 70 min,respectively.The denser outmost AlN layer was formed on the inner Al crystal layer.There is an occurrence of the interfacial reaction and metallurgy bonding in the interface layer between the coatings and NdFeB substrate.It has been found that the thickness of outmost AlN layer has a significant impact on corrosion resistance.For 50 min to deposit outmost AlN layer,AlN/Al coated NdFeB has the best corrosion resistance.
文摘通过热力学方法分析了 Al N生成反应进行的可能性 ,探讨了 Al N/ Al原位复合材料的金相组织 ,确定了增强相 Al N的存在及其尺寸大小。研究结果表明 :Al N增强相为纳米级尺寸 ,它均匀分布于共晶相中 ,基体α- Al相中没有Al N相。纳米增强相 Al N对复合材料有细化晶粒强化及弥散强化作用。
文摘The pressureless infiltration process to synthesize a silicon nitride composite was investigated. An Al-2wt%Mg alloy was infiltrated into silicon nitride preforms in the atmosphere of nitrogen. It is possible to infiltrate the Al-2wt%Mg alloy in silicon nitride preforms, The growth of the composite with useful thickness was facilitated by the presence of magnesium powder at the interface and by flowing nitrogen. The microstructure of the Si3N4-Al composite has been characterized using scanning electron microscope. During the infiltration of Si3N4 preforms, Si3N4 reacted with aluminium to form silicon and AIN. The silicon produced during the growth consumed in the formation of MgSiAIO, MgSiAlN and Al3.27Si0.47 type phases. The growth of the composite was found to proceed in two ways, depending on the oxide content in the initial preforms, First, less oxide content preforms gave rise to MgAlSiO and MgAlSiN type phases after infiltration. Second, more oxide content preforms gave rise to AlN-Al2O3 solid solution phase （AlON）, The AlON phase was only present in the composite, containing 10% aluminium in the silicon nitride preforms before infiltration.
文摘Recently, the study of nanocomposites has attracted much attention, but the powder isdifficult to be homogenized and nanoparticles are not well distributed when nanophase isintroduced into matrix via general mechanical mixing. The in situ formation of AlNsubmicron particles in Al<sub>2</sub>O<sub>3</sub> matrix has been explored to prepare AlN-Al<sub>2</sub>O<sub>3</sub> composite bymeans of reaction-bonding method.
