Sn-10Sb-5Cu lead-free solder was fabricated for high temperature application in electronic package. Wetting behaviors and interfacial reaction between such a high temperature lead-free solder and Cu substrate were inv...Sn-10Sb-5Cu lead-free solder was fabricated for high temperature application in electronic package. Wetting behaviors and interfacial reaction between such a high temperature lead-free solder and Cu substrate were investigated and compared with those of 95Pb-Sn solder. The results showed that the wetting properties of Sn-10Sb-SCu solder are superior to those of 95Pb-Sn solder in maximum wetting force, wetting time and wetting angle in the temperature range of 340-400℃. However, the surface of the Sn-10Sb-5Cu solder sample after wetting balance tests was rougher than that of 95Pb-Sn solder at the temperature lower than 360℃. In static liquid-state interracial reaction, the types and thickness of the intermetallic compounds （IMCs） of both solders were different from each other. The wetting kinetics in the Sn-10Sb-5Cu/Cu system was more rapid than that in 95Pb-Sn/Cu system, and the higher formation rate of IMCs in the former system was considered as the reason.展开更多
In the present work, the effect of Ni doping on the microstructures and properties of Zn-20 Sn high temperature lead-free solder has been investigated. Interestingly,Ni was present as the form of Ni-Zn compounds in th...In the present work, the effect of Ni doping on the microstructures and properties of Zn-20 Sn high temperature lead-free solder has been investigated. Interestingly,Ni was present as the form of Ni-Zn compounds in the microstructure of Zn-20 Sn-xNi alloy.When the Ni-doping amount was 0.2~0.4 wt.%, the presence of δ phase was found, and when the doping amoun was 0.8 wt.%, the presence of γ phase was observed. With the increase of Ni content, the liquidus temperature increased but the solidus temperature did not change obviously. In addition, the microhardness and electrical resistivities of Zn-20 Sn-xNi solder increased gradually. And the spreading area and shear strength increased firstly but decreased afterwards. When the content of Ni was 0.4 wt.%, the spreading area and shear strength of solder reached to be maximum. After the addition of 0.4 wt.% Ni, the microstructure of the interfacial intermetallic compound(IMC) layer of the interface didn't change, but the total thickness of the IMC layer reduced. The δ-phase was embedded in the grain boundary of ε-Cu Zn5, which hindered the diffusion of atoms. The thickness of IMC layer at the interface reduced, which led to the improvement of the shear strength of the interface.展开更多
A novel Zn-based high-temperature solder was developed to join copper/steel at moderate temperature. The effects of Bi and rare earth metal on the microstructures , wettability of solders as well as the mechanical pro...A novel Zn-based high-temperature solder was developed to join copper/steel at moderate temperature. The effects of Bi and rare earth metal on the microstructures , wettability of solders as well as the mechanical properties of solder joints were investigated. The results indicated that with the addition of Bi into Zn-Cu-Sn （ZCS） alloy, significant improvement in wettability is realized. When the content of Bi element is 1.5 wt. % in the solder, the spreading area researched over 200 mm^2. Furthermore, with the addition of RE, refined primary ε-CuZn5 phases were formed and the shear strength of the solder joint was largely improved.展开更多
In this paper, the preparation of 0.08BiGaO3–0.90BaTiO3–0.02LiNbO3 is investigated at pressure 3.8 GPa and temperature 1100–1200？C. Experimental results indicate that not only is the sintered rate more effective, ...In this paper, the preparation of 0.08BiGaO3–0.90BaTiO3–0.02LiNbO3 is investigated at pressure 3.8 GPa and temperature 1100–1200？C. Experimental results indicate that not only is the sintered rate more effective, but also the sintered temperature is lower under high pressure and high temperature than those of under normal pressure. It is thought that the adscititious pressure plays the key role in this process, which is discussed in detail. The composition and the structure of the as-prepared samples are recorded by XRD patterns. The result shows that the phases of Ba TiO3, BaBiO（2.77）, and Ba2Bi4Ti5O（18） with piezoelectric ceramic performance generate in the sintered samples. Furthermore, the surface morphology characteristics of the typical samples are also investigated using a scanning electron microscope. It indicates that the grain size and surface structure of the samples are closely related to the sintering temperature and sintering time. It is hoped that this study can provide a new train of thought for the preparation of lead-free piezoelectric ceramics with excellent performance.展开更多
It is important, for electronic application, to decrease the melting point of Sn-5Sb solder alloy because it is relatively high as compared with the most popular eutectic Pb-Sn solder alloy. Adding Au or Ag can decrea...It is important, for electronic application, to decrease the melting point of Sn-5Sb solder alloy because it is relatively high as compared with the most popular eutectic Pb-Sn solder alloy. Adding Au or Ag can decrease the onset melting temperature （233℃） of this alloy to 203,5℃ and 216℃, respectively. The results indicate that the Sn-5Sb-i.5Au alloy has very good ultimate tensile strength （UTS）, ductility, and fusion heat, which are better than both those of the Sn-5Sb-3.SAg and Sn-5Sb alloys. The formation of intermetallic compounds （IMCs） AuSn4 and Ag3Sn enhanced the SbSn precipitates in the solidification microstructure microstructure stability, while retained the formation of thus significantly improved the strength and ductility For all alloys, both UTS and yield stress （σy） increase with increasing strain rate and decrease with increasing temperature in tensile tests, but changes of ductility are generally small with inconsistent trends.展开更多
Two kinds of silver based medium temperature brazing filler metals(45AgCuZnSn and 60AgCuSn) were selected to braze and seal brass flange pipe and copper pipe by high frequency heating brazing. In this paper, the quali...Two kinds of silver based medium temperature brazing filler metals(45AgCuZnSn and 60AgCuSn) were selected to braze and seal brass flange pipe and copper pipe by high frequency heating brazing. In this paper, the quality of the braze was evaluated by immersion ultrasound, and the microstructure of the brazed joint was observed by SEM and EDS. The experimental results show that the high frequency heating brazing can quickly achieve the device sealing;through the ultrasonic flaw detection image calculation, the brazed bonding rate obtained by 60AgCuSn brazing is 87%, and by 45AgCuZnSn brazing is 71%;the cross-sectional area of the brazed joint obtained by two kinds of silver based medium temperature brazing filler metals is observed, the brazed joint obtained by 45AgCuZnSn brazing has defects visual, and a large amount of Zn element gathered in the defects, there is no obvious porosity in the brazed joint by 60AgCuSn brazing,and the bonding layer is dense and coherent. Through the contrast test, the choice of 60AgCuSn alloy brazing can meet the needs of high frequency brazing of brass flange pipe and copper pipe.展开更多
This article reports the effects of phosphorus addition on the melting behavior, microstructure, and mechanical properties of Sn3.0Ag0.SCu solder. The melting behavior of the solder alloys was determined by differenti...This article reports the effects of phosphorus addition on the melting behavior, microstructure, and mechanical properties of Sn3.0Ag0.SCu solder. The melting behavior of the solder alloys was determined by differential scanning calorimetry. The interracial micro- structure and phase composition of solder/Cu joints were studied by scanning electron microscopy and energy dispersive spectrometry. Thermodynamics of Cu-P phase formation at the interface between Sn3.0Ag0.5Cu0.5P solder and the Cu substrate was characterized. The results indicate that P addition into Sn3.0Ag0.5Cu solder can change the microstructure and cause the appearance of rod-like CuaP phase which is distributed randomly in the solder bulk. The Sn3.0Ag0.5Cu0.5P joint shows a mixture of ductile and brittle fracture after shear test- ing. Meanwhile, the solidus temperature of Sn3.0Ag0.5Cu solder is slightly enhanced with P addition.展开更多
(Ba_(0.3)Bi_(0.7))(Mg_(0.05)Fe_(0.6)Ti_(0.35))O_(3) ceramics were either doped with vanadium or sintered in calcined powder with the same composition.Compared to an undoped ceramic sintered without the calcined powder...(Ba_(0.3)Bi_(0.7))(Mg_(0.05)Fe_(0.6)Ti_(0.35))O_(3) ceramics were either doped with vanadium or sintered in calcined powder with the same composition.Compared to an undoped ceramic sintered without the calcined powder,both ceramics showed reduced leakage current densities(lower than 1×10^(-7) A/cm^(2))and absence of dielectric relaxation behaviors observed in frequency-and temperaturedependent dielectric measurements.The Curie temperatures of both samples were higher than 460℃.The maximum field-induced strain over the applied field,S_(max)/E_(max),of 366 pm/V of the undoped ceramic sintered without the calcined powder increased to 455 and 799 pm/V for the V-doped ceramics and the ceramics sintered with the calcined powder,respectively.The increase was related to a reduced concentration of bismuth vacancy-oxygen vacancy defect dipoles.展开更多
In order to obtain both high piezoelectric property and good temperature stability in BaTiO_(3)-based ceramics in the common usage temperature range,Sn4þand Zr4þare co-doped into BaTiO3 ceramics according to...In order to obtain both high piezoelectric property and good temperature stability in BaTiO_(3)-based ceramics in the common usage temperature range,Sn4þand Zr4þare co-doped into BaTiO3 ceramics according to the formula of Ba(Ti_(0.96)Sn_(x)Zr_(0.04-x))O_(3)(BTSZ)(x=0.01-0.4)with 1 mol%CuO being added as sintering-aid in this study.The CuO-modified BTSZ ceramics show both high piezoelectric properties and good temperature stability.Particularly,the CuO-modified Ba(Ti_(0.96)Sn_(x)Zr_(0.04-x))O_(3)ceramic displays the high piezoelectric properties of d_(33)=350 pC/N,k_(p)=49.5%at room-temperature and a weak temperature dependence of kp in the temperature range of15C and 60C.Moreover,the CuO-modified Ba(Ti_(0.96)Sn_(x)Zr_(0.04-x))O_(3)ceramic shows stable thermal aging behavior with the d33 being almost unchanged until the aging temperature of 100C,which is even higher than its Curie temperature.The high piezoelectric properties of CuO-modified Ba(Ti_(0.96)Sn_(x)Zr_(0.04-x))O_(3)ceramic were ascribed to the dense microstructure with small and uniform grain size distribution.The stable thermal aging behavior can be explained by the aging effect based on the defect dipolar model.展开更多
基金supported by the Science and Technology Program of Zhejiang Province,China (No.2008F1024)
文摘Sn-10Sb-5Cu lead-free solder was fabricated for high temperature application in electronic package. Wetting behaviors and interfacial reaction between such a high temperature lead-free solder and Cu substrate were investigated and compared with those of 95Pb-Sn solder. The results showed that the wetting properties of Sn-10Sb-SCu solder are superior to those of 95Pb-Sn solder in maximum wetting force, wetting time and wetting angle in the temperature range of 340-400℃. However, the surface of the Sn-10Sb-5Cu solder sample after wetting balance tests was rougher than that of 95Pb-Sn solder at the temperature lower than 360℃. In static liquid-state interracial reaction, the types and thickness of the intermetallic compounds （IMCs） of both solders were different from each other. The wetting kinetics in the Sn-10Sb-5Cu/Cu system was more rapid than that in 95Pb-Sn/Cu system, and the higher formation rate of IMCs in the former system was considered as the reason.
基金supported by the scientific and technological project in Fujian Province(2015H0008)
文摘In the present work, the effect of Ni doping on the microstructures and properties of Zn-20 Sn high temperature lead-free solder has been investigated. Interestingly,Ni was present as the form of Ni-Zn compounds in the microstructure of Zn-20 Sn-xNi alloy.When the Ni-doping amount was 0.2~0.4 wt.%, the presence of δ phase was found, and when the doping amoun was 0.8 wt.%, the presence of γ phase was observed. With the increase of Ni content, the liquidus temperature increased but the solidus temperature did not change obviously. In addition, the microhardness and electrical resistivities of Zn-20 Sn-xNi solder increased gradually. And the spreading area and shear strength increased firstly but decreased afterwards. When the content of Ni was 0.4 wt.%, the spreading area and shear strength of solder reached to be maximum. After the addition of 0.4 wt.% Ni, the microstructure of the interfacial intermetallic compound(IMC) layer of the interface didn't change, but the total thickness of the IMC layer reduced. The δ-phase was embedded in the grain boundary of ε-Cu Zn5, which hindered the diffusion of atoms. The thickness of IMC layer at the interface reduced, which led to the improvement of the shear strength of the interface.
文摘A novel Zn-based high-temperature solder was developed to join copper/steel at moderate temperature. The effects of Bi and rare earth metal on the microstructures , wettability of solders as well as the mechanical properties of solder joints were investigated. The results indicated that with the addition of Bi into Zn-Cu-Sn （ZCS） alloy, significant improvement in wettability is realized. When the content of Bi element is 1.5 wt. % in the solder, the spreading area researched over 200 mm^2. Furthermore, with the addition of RE, refined primary ε-CuZn5 phases were formed and the shear strength of the solder joint was largely improved.
基金Project supported by the National Natural Science Foundation of China(Grant No.51172089)the Natural Science Foundation of Education Department of Guizhou Province,China(Grant Nos.KY[2013]183 and LH[2015]7232)the Research Fund for the Doctoral Program of Tongren University,China(Grant No.DS1302)
文摘In this paper, the preparation of 0.08BiGaO3–0.90BaTiO3–0.02LiNbO3 is investigated at pressure 3.8 GPa and temperature 1100–1200？C. Experimental results indicate that not only is the sintered rate more effective, but also the sintered temperature is lower under high pressure and high temperature than those of under normal pressure. It is thought that the adscititious pressure plays the key role in this process, which is discussed in detail. The composition and the structure of the as-prepared samples are recorded by XRD patterns. The result shows that the phases of Ba TiO3, BaBiO（2.77）, and Ba2Bi4Ti5O（18） with piezoelectric ceramic performance generate in the sintered samples. Furthermore, the surface morphology characteristics of the typical samples are also investigated using a scanning electron microscope. It indicates that the grain size and surface structure of the samples are closely related to the sintering temperature and sintering time. It is hoped that this study can provide a new train of thought for the preparation of lead-free piezoelectric ceramics with excellent performance.
文摘It is important, for electronic application, to decrease the melting point of Sn-5Sb solder alloy because it is relatively high as compared with the most popular eutectic Pb-Sn solder alloy. Adding Au or Ag can decrease the onset melting temperature （233℃） of this alloy to 203,5℃ and 216℃, respectively. The results indicate that the Sn-5Sb-i.5Au alloy has very good ultimate tensile strength （UTS）, ductility, and fusion heat, which are better than both those of the Sn-5Sb-3.SAg and Sn-5Sb alloys. The formation of intermetallic compounds （IMCs） AuSn4 and Ag3Sn enhanced the SbSn precipitates in the solidification microstructure microstructure stability, while retained the formation of thus significantly improved the strength and ductility For all alloys, both UTS and yield stress （σy） increase with increasing strain rate and decrease with increasing temperature in tensile tests, but changes of ductility are generally small with inconsistent trends.
基金supported by the National Key R&D Program of China(Grant No. 2017YFB0305702)。
文摘Two kinds of silver based medium temperature brazing filler metals(45AgCuZnSn and 60AgCuSn) were selected to braze and seal brass flange pipe and copper pipe by high frequency heating brazing. In this paper, the quality of the braze was evaluated by immersion ultrasound, and the microstructure of the brazed joint was observed by SEM and EDS. The experimental results show that the high frequency heating brazing can quickly achieve the device sealing;through the ultrasonic flaw detection image calculation, the brazed bonding rate obtained by 60AgCuSn brazing is 87%, and by 45AgCuZnSn brazing is 71%;the cross-sectional area of the brazed joint obtained by two kinds of silver based medium temperature brazing filler metals is observed, the brazed joint obtained by 45AgCuZnSn brazing has defects visual, and a large amount of Zn element gathered in the defects, there is no obvious porosity in the brazed joint by 60AgCuSn brazing,and the bonding layer is dense and coherent. Through the contrast test, the choice of 60AgCuSn alloy brazing can meet the needs of high frequency brazing of brass flange pipe and copper pipe.
文摘This article reports the effects of phosphorus addition on the melting behavior, microstructure, and mechanical properties of Sn3.0Ag0.SCu solder. The melting behavior of the solder alloys was determined by differential scanning calorimetry. The interracial micro- structure and phase composition of solder/Cu joints were studied by scanning electron microscopy and energy dispersive spectrometry. Thermodynamics of Cu-P phase formation at the interface between Sn3.0Ag0.5Cu0.5P solder and the Cu substrate was characterized. The results indicate that P addition into Sn3.0Ag0.5Cu solder can change the microstructure and cause the appearance of rod-like CuaP phase which is distributed randomly in the solder bulk. The Sn3.0Ag0.5Cu0.5P joint shows a mixture of ductile and brittle fracture after shear test- ing. Meanwhile, the solidus temperature of Sn3.0Ag0.5Cu solder is slightly enhanced with P addition.
基金supported by Elements Science and Technology Project of the Ministry of Education,Culture,Sports,Science and Technology,Japan.
文摘(Ba_(0.3)Bi_(0.7))(Mg_(0.05)Fe_(0.6)Ti_(0.35))O_(3) ceramics were either doped with vanadium or sintered in calcined powder with the same composition.Compared to an undoped ceramic sintered without the calcined powder,both ceramics showed reduced leakage current densities(lower than 1×10^(-7) A/cm^(2))and absence of dielectric relaxation behaviors observed in frequency-and temperaturedependent dielectric measurements.The Curie temperatures of both samples were higher than 460℃.The maximum field-induced strain over the applied field,S_(max)/E_(max),of 366 pm/V of the undoped ceramic sintered without the calcined powder increased to 455 and 799 pm/V for the V-doped ceramics and the ceramics sintered with the calcined powder,respectively.The increase was related to a reduced concentration of bismuth vacancy-oxygen vacancy defect dipoles.
基金supported by the Natural Science Foundation of Shandong Province(Grant No.ZR2010EM005)the Specialized Research Fund for the Doctoral Program of Higher Education(Grant No.20090131110015)the National Natural Science Foundation of China(Grant No.51172128).
文摘In order to obtain both high piezoelectric property and good temperature stability in BaTiO_(3)-based ceramics in the common usage temperature range,Sn4þand Zr4þare co-doped into BaTiO3 ceramics according to the formula of Ba(Ti_(0.96)Sn_(x)Zr_(0.04-x))O_(3)(BTSZ)(x=0.01-0.4)with 1 mol%CuO being added as sintering-aid in this study.The CuO-modified BTSZ ceramics show both high piezoelectric properties and good temperature stability.Particularly,the CuO-modified Ba(Ti_(0.96)Sn_(x)Zr_(0.04-x))O_(3)ceramic displays the high piezoelectric properties of d_(33)=350 pC/N,k_(p)=49.5%at room-temperature and a weak temperature dependence of kp in the temperature range of15C and 60C.Moreover,the CuO-modified Ba(Ti_(0.96)Sn_(x)Zr_(0.04-x))O_(3)ceramic shows stable thermal aging behavior with the d33 being almost unchanged until the aging temperature of 100C,which is even higher than its Curie temperature.The high piezoelectric properties of CuO-modified Ba(Ti_(0.96)Sn_(x)Zr_(0.04-x))O_(3)ceramic were ascribed to the dense microstructure with small and uniform grain size distribution.The stable thermal aging behavior can be explained by the aging effect based on the defect dipolar model.
