To improve the properties of Sn10Sb8Cu solder alloy, two new solders (SnSbCuAg and SnSbCuNi) were formed by adding small amounts of Ag or Ni into the solder alloy. The results show that the melting point of the SnSb...To improve the properties of Sn10Sb8Cu solder alloy, two new solders (SnSbCuAg and SnSbCuNi) were formed by adding small amounts of Ag or Ni into the solder alloy. The results show that the melting point of the SnSbCuAg solder alloy decreases by 14.1℃ and the spreading area increases by 16.5% compared to the matrix solder. The melting point of the SnSbCuNi solder alloy decreases by 5.4℃ and the spreading area is slightly less than that of the matrix solder. Microstructure analysis shows that adding trace Ag makes the melting point decline due to the dispersed distribution of SnAg phase with low melting point. Adding trace Ni, Cu6Sn5 and (Cu, Ni)6Sn5 with polyhedron shape on the copper substrate can be easily seen in the SnSbCuNi solder alloy, which makes the viscosity of the melting solder increase and the spreading property of the solder decline.展开更多
The microstructural formation and properties of Sn-2.5Bi-xln-lZn-0.3Ag (in wt%) alloys and the evolution of soldered interfaces on a Cu substrate were investigated. Apart from the relatively low melting point (abou...The microstructural formation and properties of Sn-2.5Bi-xln-lZn-0.3Ag (in wt%) alloys and the evolution of soldered interfaces on a Cu substrate were investigated. Apart from the relatively low melting point (about 195C), which is close to that of conventional eutectic Sn-Pb solder, the investigated solder presents superior wettability, solderability, and ductility. The refined equiaxial grains enhance the me- chanical properties, and the embedded bulk intermetallic compounds (IMCs) (Cu6Sn5 and CusZns) and granular Bi particles improve the joint reliability. The addition of In reduces the solubility of Zn in the 13-Sn matrix and strongly influences the separation and growth behaviors of the IMCs. The soldered interface of Sn-2.5Bi-xln-lZn-0.3Ag/Cu consists of Cu-Zn and Cu-Sn IMC layers.展开更多
An Al–Ti–Cu–Si solid–liquid dual-phase alloy that exhibits good wettability and appropriate interfacial reaction with SiC at 500–600°C was designed for SiC–metal joining. The microstructure, phases, differe...An Al–Ti–Cu–Si solid–liquid dual-phase alloy that exhibits good wettability and appropriate interfacial reaction with SiC at 500–600°C was designed for SiC–metal joining. The microstructure, phases, differential thermal curves, and high-temperature wetting behavior of the alloy were analyzed using scanning electron microscopy, X-ray diffraction analysis, differential scanning calorimetry, and the sessile drop method. The experimental results show that the 76.5Al–8.5Ti–5Cu–10Si alloy is mainly composed of Al–Al2Cu and Al–Si hypoeutectic low-melting-point microstructures (493–586°C) and the high-melting-point intermetallic compound AlTiSi (840°C). The contact angle, determined by high-temperature wetting experiments, is approximately 54°. Furthermore, the wetting interface is smooth and contains no obvious defects. Metallurgical bonding at the interface is attributable to the reaction between Al and Si in the alloy and ceramic, respectively. The formation of the brittle Al4C3phase at the interface is suppressed by the addition of 10wt% Si to the alloy. ? 2017, University of Science and Technology Beijing and Springer-Verlag Berlin Heidelberg.展开更多
The growth rule of the interfacial intermetallic compound (IMC) and the degradation of shear strength of Sn-0.SAg-0.5Cu-2.0Bi-0.05Ni (SACBN)/Cu solder joints were investigated in comparison with Sn-3.0Ag-0.5Cu (S...The growth rule of the interfacial intermetallic compound (IMC) and the degradation of shear strength of Sn-0.SAg-0.5Cu-2.0Bi-0.05Ni (SACBN)/Cu solder joints were investigated in comparison with Sn-3.0Ag-0.5Cu (SAC305)/ Cu solder joints aging at 373, 403, and 438 K. The results show that (Cul-x,Nix)6Sn5 phase forms between the SACBN solder and Cu substrate during soldering. The interracial IMC thickens constantly with the aging time increasing, and the higher the aging temperature, the faster the IMC layer grows. Compared with the SAC305/Cu couple, the SACBN/Cu couple exhibits a lower layer growth coefficient. The activation energies of IMC growth for SACBN/Cu and SAC305/Cu couples are 111.70 and 82.35 kJ/mol, respectively. In general, the shear strength of aged solder joints declines continuously. However, SACBN/Cu solder joints exhibit a better shear strength than SAC305/Cu solder joints.展开更多
A new type of lead-free solder alloy Sn2.0Ag0.7CuRE was fabricated under vacuum condition. The microstructure and properties of the material, such as tensile strength, elongation, melting range, conductance and spread...A new type of lead-free solder alloy Sn2.0Ag0.7CuRE was fabricated under vacuum condition. The microstructure and properties of the material, such as tensile strength, elongation, melting range, conductance and spreading area were all investigated. Result shows that when the content of RE ≤ 0.1% (mass fraction), RE distribute uniformly in the solder alloy, and the tensile strength and conductance of Sn2.0Ag0.7CuRE solder alloy are better than those of traditional Sn37Pb solder. Its elongation and spreading area are almost equal to those of Sn37Pb solder. When the content of RE reaches 0.5%, RE compounds can be easily found around the boundaries of grains and phases, and the tensile strength and elongation and spreading area of Sn2.0Ag0.7CuRE solder alloy all decrease sharply. Therefore, RE amount added to the Sn2.0Ag0.7CuRE solder alloy under 0.1% is proper.展开更多
The growth of Au-Sn intermetallic compounds(IMCs) is a major concern to the reliability of solder joints in microelectronic,optoelectronic and micro-electronic-mechanical system(MEMS) which has a layer of Au metalliza...The growth of Au-Sn intermetallic compounds(IMCs) is a major concern to the reliability of solder joints in microelectronic,optoelectronic and micro-electronic-mechanical system(MEMS) which has a layer of Au metallization on the surface of components or leads.This paper presented the growth behavior of Au-Sn IMCs at interfaces of Au metallization and Sn-based solder joints with the addition of Cu alloying element during aging process,and growth coefficients of the Au-Sn IMCs were calculated.Results on the interfacial reaction between Sn-xCu solders and Au metallization during aging process show that three layers of Au-Sn IMCs including AuSn,AuSn2 and AuSn4 formed at the interface region.The thickness of each Au-Sn IMC layer vs square root of aging time follows linear relationship.Calculation of the IMC growth coefficients shows that the diffusion coefficients decrease with the addition Cu elements,which indicates that Cu addition suppresses the growth of Au-Sn IMCs layer.展开更多
The present investigation is based on the results of a directionally solidified (DS) Sn-9 wt%Zn-2 wt%Cu alloy, including primary/secondary/tertiary dendrite arm spacings of the Sn-rich matrix, the morphologies of th...The present investigation is based on the results of a directionally solidified (DS) Sn-9 wt%Zn-2 wt%Cu alloy, including primary/secondary/tertiary dendrite arm spacings of the Sn-rich matrix, the morphologies of the eutectic mixture and the corresponding interphase spacing, the nature and proportion of the Cu-Zn intermetallic compound (IMC). The main purpose is to establish interrelations of these microstructure features with experimental solidification thermal parameters, such as cooling rates and growth rates (v), macrosegregation and hardness. Such interrelations are interesting for both industry and academy since they represent a tool permitting the preprogramming of final properties based on the design of the microstructure. In the case of Sn-Zn-Cu alloys, hardly anything is known about the combined effects of the length scale of the microstructure and fraction and distribution of the primary IMC on hardness. The alloy microstructure is composed of a β-Sn dendritic region, surrounded by a eutectic mixture of α-Zn and β-Sn phases and the γ-Cu5Zn8 IMC. The eutectic interphase spacing varies in the range 1.2-3.6 μm, with the α-Zn phase having a globular morphology for ν 〉 0.5 mm/s and a needle-like morphology for ν 〈 0.3 mm/s. A modified Hall-Petch-type experimental expression relating hardness to the interphase spacing is proposed.展开更多
基金supported by the Program for Science & Technology Innovation Talents in Universities of Henan Province (No.2010HASTIT032)the City Key Technologies R & D Program of Luoyang (No.0801038A), China
文摘To improve the properties of Sn10Sb8Cu solder alloy, two new solders (SnSbCuAg and SnSbCuNi) were formed by adding small amounts of Ag or Ni into the solder alloy. The results show that the melting point of the SnSbCuAg solder alloy decreases by 14.1℃ and the spreading area increases by 16.5% compared to the matrix solder. The melting point of the SnSbCuNi solder alloy decreases by 5.4℃ and the spreading area is slightly less than that of the matrix solder. Microstructure analysis shows that adding trace Ag makes the melting point decline due to the dispersed distribution of SnAg phase with low melting point. Adding trace Ni, Cu6Sn5 and (Cu, Ni)6Sn5 with polyhedron shape on the copper substrate can be easily seen in the SnSbCuNi solder alloy, which makes the viscosity of the melting solder increase and the spreading property of the solder decline.
基金the National Natural Science Foundation of China(No.51077099)Shang hai Baosteel Group Co.(No.50834011)
文摘The microstructural formation and properties of Sn-2.5Bi-xln-lZn-0.3Ag (in wt%) alloys and the evolution of soldered interfaces on a Cu substrate were investigated. Apart from the relatively low melting point (about 195C), which is close to that of conventional eutectic Sn-Pb solder, the investigated solder presents superior wettability, solderability, and ductility. The refined equiaxial grains enhance the me- chanical properties, and the embedded bulk intermetallic compounds (IMCs) (Cu6Sn5 and CusZns) and granular Bi particles improve the joint reliability. The addition of In reduces the solubility of Zn in the 13-Sn matrix and strongly influences the separation and growth behaviors of the IMCs. The soldered interface of Sn-2.5Bi-xln-lZn-0.3Ag/Cu consists of Cu-Zn and Cu-Sn IMC layers.
基金financially supported by the High-Tech Research and Development Program of China(No.SS2013AA031305)the Key Technologies R&D Program of Tianjin(No.12ZCDGGX49100)
文摘An Al–Ti–Cu–Si solid–liquid dual-phase alloy that exhibits good wettability and appropriate interfacial reaction with SiC at 500–600°C was designed for SiC–metal joining. The microstructure, phases, differential thermal curves, and high-temperature wetting behavior of the alloy were analyzed using scanning electron microscopy, X-ray diffraction analysis, differential scanning calorimetry, and the sessile drop method. The experimental results show that the 76.5Al–8.5Ti–5Cu–10Si alloy is mainly composed of Al–Al2Cu and Al–Si hypoeutectic low-melting-point microstructures (493–586°C) and the high-melting-point intermetallic compound AlTiSi (840°C). The contact angle, determined by high-temperature wetting experiments, is approximately 54°. Furthermore, the wetting interface is smooth and contains no obvious defects. Metallurgical bonding at the interface is attributable to the reaction between Al and Si in the alloy and ceramic, respectively. The formation of the brittle Al4C3phase at the interface is suppressed by the addition of 10wt% Si to the alloy. ? 2017, University of Science and Technology Beijing and Springer-Verlag Berlin Heidelberg.
基金financially supported by the National Natural Science Foundation of China(No.U0734006)Shenzhen Tongfang Electronic New Material Co.,Ltd
文摘The growth rule of the interfacial intermetallic compound (IMC) and the degradation of shear strength of Sn-0.SAg-0.5Cu-2.0Bi-0.05Ni (SACBN)/Cu solder joints were investigated in comparison with Sn-3.0Ag-0.5Cu (SAC305)/ Cu solder joints aging at 373, 403, and 438 K. The results show that (Cul-x,Nix)6Sn5 phase forms between the SACBN solder and Cu substrate during soldering. The interracial IMC thickens constantly with the aging time increasing, and the higher the aging temperature, the faster the IMC layer grows. Compared with the SAC305/Cu couple, the SACBN/Cu couple exhibits a lower layer growth coefficient. The activation energies of IMC growth for SACBN/Cu and SAC305/Cu couples are 111.70 and 82.35 kJ/mol, respectively. In general, the shear strength of aged solder joints declines continuously. However, SACBN/Cu solder joints exhibit a better shear strength than SAC305/Cu solder joints.
文摘A new type of lead-free solder alloy Sn2.0Ag0.7CuRE was fabricated under vacuum condition. The microstructure and properties of the material, such as tensile strength, elongation, melting range, conductance and spreading area were all investigated. Result shows that when the content of RE ≤ 0.1% (mass fraction), RE distribute uniformly in the solder alloy, and the tensile strength and conductance of Sn2.0Ag0.7CuRE solder alloy are better than those of traditional Sn37Pb solder. Its elongation and spreading area are almost equal to those of Sn37Pb solder. When the content of RE reaches 0.5%, RE compounds can be easily found around the boundaries of grains and phases, and the tensile strength and elongation and spreading area of Sn2.0Ag0.7CuRE solder alloy all decrease sharply. Therefore, RE amount added to the Sn2.0Ag0.7CuRE solder alloy under 0.1% is proper.
基金This work was financially supported by the National Natural Science Foundation of China ( No 50675047/ E052105)Joint Project between Samsung Electronics Co Ltd( Korea) and Harbin Institute of Technology( HIT)
文摘The growth of Au-Sn intermetallic compounds(IMCs) is a major concern to the reliability of solder joints in microelectronic,optoelectronic and micro-electronic-mechanical system(MEMS) which has a layer of Au metallization on the surface of components or leads.This paper presented the growth behavior of Au-Sn IMCs at interfaces of Au metallization and Sn-based solder joints with the addition of Cu alloying element during aging process,and growth coefficients of the Au-Sn IMCs were calculated.Results on the interfacial reaction between Sn-xCu solders and Au metallization during aging process show that three layers of Au-Sn IMCs including AuSn,AuSn2 and AuSn4 formed at the interface region.The thickness of each Au-Sn IMC layer vs square root of aging time follows linear relationship.Calculation of the IMC growth coefficients shows that the diffusion coefficients decrease with the addition Cu elements,which indicates that Cu addition suppresses the growth of Au-Sn IMCs layer.
基金financial support provided by FAPESP(So Paulo Research Foundation,Brazil:Grants 2013/08259-3 and 2015/11863-5)CNPq
文摘The present investigation is based on the results of a directionally solidified (DS) Sn-9 wt%Zn-2 wt%Cu alloy, including primary/secondary/tertiary dendrite arm spacings of the Sn-rich matrix, the morphologies of the eutectic mixture and the corresponding interphase spacing, the nature and proportion of the Cu-Zn intermetallic compound (IMC). The main purpose is to establish interrelations of these microstructure features with experimental solidification thermal parameters, such as cooling rates and growth rates (v), macrosegregation and hardness. Such interrelations are interesting for both industry and academy since they represent a tool permitting the preprogramming of final properties based on the design of the microstructure. In the case of Sn-Zn-Cu alloys, hardly anything is known about the combined effects of the length scale of the microstructure and fraction and distribution of the primary IMC on hardness. The alloy microstructure is composed of a β-Sn dendritic region, surrounded by a eutectic mixture of α-Zn and β-Sn phases and the γ-Cu5Zn8 IMC. The eutectic interphase spacing varies in the range 1.2-3.6 μm, with the α-Zn phase having a globular morphology for ν 〉 0.5 mm/s and a needle-like morphology for ν 〈 0.3 mm/s. A modified Hall-Petch-type experimental expression relating hardness to the interphase spacing is proposed.