An experiment procedure was presented for the synthesis of γ-AIOOH nanoparticles by a dehydration process which employed the solution of H202 as dehydrator. The phase and morphology of the product were investigated b...An experiment procedure was presented for the synthesis of γ-AIOOH nanoparticles by a dehydration process which employed the solution of H202 as dehydrator. The phase and morphology of the product were investigated by XRD and TEM. The tribological properties of γ-AIOOH nanoparticles with the average diameter of 15 nm as additives in liquid paraffin were investigated by a four-ball tester, and the worn surfaces were analyzed by SEM and EDS. Results show that the average size of synthesized γ-AIOOH nanoparticles increases with the increase of the pH value and temperature of the reactant. The γ-AIOOH nanoparticles as additives could exhibit good tribological properties due to their covering effect, which prevents the direct contact of asperities and reduces the adhesion. As the real area of contact decreases with the decrease of applied load, the optimum concentration varies from 0.4 % to 0.1% when the applied load decreases from 294 N to 200 N.展开更多
Three-dimensional thermo-electrical finite element analyses were conducted to simulate the current density and temperature distributions in solder bump joints with different pad geometries.The effects of pad thickness...Three-dimensional thermo-electrical finite element analyses were conducted to simulate the current density and temperature distributions in solder bump joints with different pad geometries.The effects of pad thickness,diameter and shape on current density and temperate distributions were investigated respectively.It was found that pads with larger thickness or/and diameter could reduce current density and temperature in solder bump significantly.Pad shapes affected the current density and temperature distributions in solder bumps.The relatively low current density and temperature didn＇t occur in the bump joint with traditional rounded pad but occurred in bump joints with octagonal and nonagonal pads respectively.Therefore,optimized pad geometry may be designed to alleviate the current crowding effect and reduce the bump temperature,and therefore delay electromigration failure and increase the mean-time-to-failure.展开更多
基金Sponsored by the Excellent Young Scholars Research Fund of Beijing Institute of Technology(2006Y0411)
文摘An experiment procedure was presented for the synthesis of γ-AIOOH nanoparticles by a dehydration process which employed the solution of H202 as dehydrator. The phase and morphology of the product were investigated by XRD and TEM. The tribological properties of γ-AIOOH nanoparticles with the average diameter of 15 nm as additives in liquid paraffin were investigated by a four-ball tester, and the worn surfaces were analyzed by SEM and EDS. Results show that the average size of synthesized γ-AIOOH nanoparticles increases with the increase of the pH value and temperature of the reactant. The γ-AIOOH nanoparticles as additives could exhibit good tribological properties due to their covering effect, which prevents the direct contact of asperities and reduces the adhesion. As the real area of contact decreases with the decrease of applied load, the optimum concentration varies from 0.4 % to 0.1% when the applied load decreases from 294 N to 200 N.
文摘Three-dimensional thermo-electrical finite element analyses were conducted to simulate the current density and temperature distributions in solder bump joints with different pad geometries.The effects of pad thickness,diameter and shape on current density and temperate distributions were investigated respectively.It was found that pads with larger thickness or/and diameter could reduce current density and temperature in solder bump significantly.Pad shapes affected the current density and temperature distributions in solder bumps.The relatively low current density and temperature didn＇t occur in the bump joint with traditional rounded pad but occurred in bump joints with octagonal and nonagonal pads respectively.Therefore,optimized pad geometry may be designed to alleviate the current crowding effect and reduce the bump temperature,and therefore delay electromigration failure and increase the mean-time-to-failure.
