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A New Technique for Brazing Porous Copper to Copper Substrate Using CuNiSnP Amorphous Filler Metal
(2025-11-01)
Mookam, Niwat
;
Jattakul, Prajak
;
Ariga, Tadashi
;
Kanlayasiri, Kannachai
Furnace brazing is a common method for bonding porous metal to a substrate. However, it typically involves lengthy brazing times. This research introduces a novel rapid brazing technique to join porous copper to copper substrates. Using CuNiSnP amorphous filler metal, porous copper specimens were brazed under varying currents (250-1000 A) and times (900-1100 ms). Results showed successful joining without macroscopic deformation of the porous copper, and the brazing times were significantly shorter than those of traditional methods. Microstructural analysis revealed primary alpha, primary beta, and eutectic structures in the joint, all of which were influenced by brazing current and time. Adjusting the brazing conditions altered the morphology of the primary alpha structure, ranging from equiaxed to columnar dendrites, which in turn affected the joint's mechanical properties. The proposed technique offers an efficient method to manipulate joint microstructures for bonding porous copper to copper substrates, potentially improving manufacturing efficiency in industries such as heat exchangers or catalytic converters.
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EFFECT OF DIPPING SOLDERING ON THICKNESS AND INTERMETALLIC COMPOUND MORPHOLOGY BETWEEN Sn-3.0Cu LEAD-FREE SOLDER AND COPPER SUBSTRATE
(2022-01-01)
Mookam, Niwat
;
Kanlayasiri, Kannachai
The thickness and morphology of intermetallic compounds formed between Sn-3.0Cu lead-free solder and the copper substrate were investigated. In the experiment, the dipping soldering was performed at 350°C using Sn-3.0Cu lead-free solder for various dipping time lengths of 5, 10, 20, 50, 75 and 100s, respectively. The results indicated that η- Cu6Sn5 intermetallic phase was found to exist between the lead-free solder and the copper substrate. The formation of an ε-Cu3Sn particles on the η- Cu6Sn5 surface and grain boundary was found only when the substrate was soldered for 75 and 100s. The long soldering time and formation of ε-Cu3Sn particles resulted in the morphology of the η- Cu6Sn5 IMC changed from scallop shape to more round. Nevertheless, the thickness and morphology of intermetallic compounds was also found to be influenced by the diffusion controlled process.
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Effects of Ni Content on Melting Behaviors and Wettability of SnBiAgNi Lead-Free Solder
(2022-01-01)
Mookam, Niwat
;
Jattakul, Prajak
;
Kanlayasiri, Kannachai
This research aimed to study the effects of Ni content on melting behaviors and wettability of SnBiAgNi lead-free solder. Sn-58Bi-0.05Ag was used as the base solder, and Ni was then put in by 0.05, 0.10, 0.50 or 1.00 wt%. Solidus and liquidus temperatures of the solder alloys were examined to study melting behaviors. The Ni content changed the solidus and liquidus temperatures, and Sn-58Bi-0.05Ag-0.10Ni possessed the lowest solidus and liquidus temperatures. Sn-58Bi-0.05Ag-0.10Ni also provided the narrowest pasty range. Wettability of the solders on the copper substrate was expressed in terms of spread factor. The addition of Ni improved the wettability of the base solder, and Sn-58Bi-0.05Ag-0.10Ni provided the highest spread factor.
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Influence of cooling conditions on microstructure and mechanical property of Sn-0.3Ag-0.7Cu lead-free solder
(2021-01-01)
Jattakul, Prajak
;
Madsa, Tavee
;
Sunasuan, Piyawan
;
Mookam, Niwat
This research has investigated the influence of cooling conditions on the microstructure and mechanical properties i.e., tensile strength and microhardness of Sn-0.3Ag-0.7Cu lead-free solder. In the experiments, casting was performed at 300°C with comparison between copper and stainless steel molds under slow and fast cooled conditions. X-ray diffractometer confirmed the presence of Cu6Sn5 and Ag3Sn phases in the solder matrix. Lead-free solder solidified under slow cooled conditions exhibited β-Sn matrix with larger grain growth as compared to the fast cooled solder. The eutectic area of intermetallic compound (IMC) was found to increase with cooling rate. The tensile strength of slow cooled solder was greater than fast cooled solder for both molds. In addition, the microhardness of the solder was also influenced by cooling rate. The dimples size of facture surface was decreased by higher cooling rate. A greater eutectic area of the Cu6Sn5 and Ag3Sn phases of initial β-Sn matrix lead to lower values of the mechanical property from fast cooled conditions.
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Brazing of Porous Copper Foam with Copper Sheet Using CuNiSnP Amorphous Filler Metal
(2021-01-01)
Mookam, Niwat
;
Jattakul, Prajak
;
Rakphet, Tipsuda
;
Kanlayasiri, Kannachai
This research studies effects of the brazing time on interfacial microstructure of brazed joint between the porous copper foam (PCF) and Cu substrate using CuNiSnP amorphous filler metal. To examine the interfacial microstructure and its properties, an assessment of PCF/CuNiSnP/Cu brazed joints was conducted after electric furnace brazing under hydrogen (H2) atmosphere. The results showed that the interfacial microstructure was thick for short brazing time specimens and thin for prolonged brazing time specimens. The interfacial microstructures consisted of Cu-rich solid solution, (Cu, Ni)3P, and Cu3P as a eutectic structure discovered in the brazing region at different brazing times of 5, 10, and 20 min. Only the Cu-rich solid solution and (Cu, Ni)3P were found in the specimen with brazing time of 30 min. indicating that different brazing times affected interfacial microstructures and therefore reliability of the brazed joints.
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Effects of substrate annealing on wettability and intermetallic compound formation in Sn–3.0Cu/Cu systems
(2019-07-01)
Mookam, Niwat
;
Kanlayasiri, Kannachai
This paper investigates the effects of Cu substrate annealing on the wettability of Sn–3.0Cu lead-free solder and the subsequent growth of the intermetallic compounds that are formed at the interface between the solder and the substrate. The annealing processes yielded various grain sizes, grain orientations, and residual strains within the substrates. Then, effects of the Cu substrates on the wetting and intermetallic formation were studied via reflow soldering using Sn–3.0Cu lead-free solder. The annealed substrates were compared to an unannealed Cu reference at soldering times of 20, 40, 60 and 120 s. The experimental results demonstrated that the substrate grain orientation, residual strain and grain size exert no influence on the solder wettability. After soldering, only a η-Cu<inf>6</inf>Sn<inf>5</inf> intermetallic compound was observed in the interfacial layer for both the reference and annealed copper substrates. The thickness of the η-Cu<inf>6</inf>Sn<inf>5</inf> layer was found to be independent of the substrate grain size but increased as the misorientation angle and the residual strain in the substrate increased.
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Influences of soldering time on wettability and intermetallic phase between Sn-3.0Cu solder and copper substrate
(2018-08-14)
Mookam, Niwat
;
Kanlayasiri, Kannachai
In this paper, the influences of soldering time on the wettability and intermetallic phase between Sn-3.0Cu lead-free solder and copper substrate were investigated. Reflow soldering was performed at 350 ° C under variable soldering times of 10, 20, 40, 60, 120, 240 and 480 s. The results indicated that the wettability and intermetallic growth depend on the soldering time. In addition, the Cu<inf>6</inf>Sn<inf>5</inf> and Cu<inf>3</inf>Sn intermetallic phases with a hexagonal crystal structure were found between the lead-free solder and the copper substrate. The growth of intermetallic phases increased with soldering time, and the growth of intermetallic phases remarkably depended on grain boundary diffusion and was volume diffusion-controlled for Cu<inf>6</inf>Sn<inf>5</inf> and Cu<inf>3</inf>Sn, respectively.
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Evolution of Intermetallic Compounds between Sn-0.3Ag-0.7Cu Low-silver Lead-free Solder and Cu Substrate during Thermal Aging
(2012-01-01)
Mookam, Niwat
;
Kanlayasiri, Kannachai
The growth, transformation, and lattice structure of intermetallic compounds formed between Sn-0.3Ag-0.7Cu lead-free solder and copper substrate were investigated. Dip soldering was used to initiate the reaction between the solder and substrate. An η-Cu <inf>6</inf>Sn <inf>5</inf> intermetallic phase possessing a hexagonal lattice structure was found at the as-soldered interface. Thermal aging at a number of conditions resulted in the formation of a Cu <inf>3</inf>Sn intermetallic phase between the Cu <inf>6</inf>Sn <inf>5</inf> layer and the copper substrate. e{open}-Cu <inf>3</inf>Sn with an orthorhombic lattice structure was found together with hexagonal Cu <inf>3</inf>Sn. Subsequently, the activation energies of the intermetallic phases were calculated and compared to results obtained from the literature. The comparison showed that good agreement existed between the findings from this study and literature data within a similar temperature range. © 2012 The Chinese Society for Metals.
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Effect of soldering condition on formation of intermetallic phases developed between Sn-0.3Ag-0.7Cu low-silver lead-free solder and Cu substrate
(2011-05-26)
Mookam, Niwat
;
Kanlayasiri, Kannachai
In this paper, effect of soldering time and temperature on formation of intermetallic compounds developed between Sn-0.3Ag-0.7Cu lead-free solder and copper substrate was investigated. Dip soldering was performed at 250, 270, and 290 °C with soldering time of 5, 10, 15, and 20 s. Either ε-Cu <inf>3</inf>Sn or η-Cu<inf>6</inf>Sn<inf>5</inf> intermetallic phase was found at the interface between the solder and the substrate depending on the soldering condition, i.e., soldering time and soldering temperature. ε-Cu<inf>3</inf>Sn was found only when the substrate was soldered at 250 °C for 5 and 10 s. At other soldering conditions, only η-Cu <inf>6</inf>Sn<inf>5</inf> was found at the interfacial zone. Crystal structure of ε-Cu<inf>3</inf>Sn intermetallic phase was orthorhombic, and it was hexagonal structure for η-Cu<inf>6</inf>Sn<inf>5</inf>. Transformation of the intermetallic phases was also discussed. © 2011 Elsevier B.V. All rights reserved.

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