Special feature This is resin flux cored lead free solder made by Sn and Cu, which can solder easily to Al wire coated by urethane or the other materials. The flux consist of high moisture adsorption materials, so need to wash with water after soldering. Evaluation of special characteristic A.Evaluation of special characteristic 1.Electrolytic corrosion 2.Washability test of flux residue 2-1.Ionic residue 2-2.Corrosion 3.Solderability B.Basic characteristic 1. Solder alloy 1-1:Alloy composition 1-2:melting point 2. Flux content 3. Halide content 4. Flux expansion 5. Insulation resistance 6. Voltage-applied moisture resistance (Migration test) Characteristics Solder alloy Flux Resin flux cored solder Table1. Characteristics of R23-C601-3 Test items Characteristic Test method Alloy composition Sn:Balance Cu:3.0 JIS Z 3910 Solidus temperature 227 Liquidus temperature 312 The type of flux Fluoride Halide content 20% JIS Z 3197 8.1.4.2.1 Flux content 3.0% JIS Z 3197 8.1.2 Ionic residue 1.0µg NaCl /in 2 JIS Z 3197 8.5.2 Corrosion No corrosion JIS Z 3197 8.4.1 Expansion Cu 77% Al 75% JIS Z 3197 8.3.1.1 Initial 4.7E+13 Ω JIS Z 3197 8.5.3 Insulation After 168h 3.0E+8 Ω Condition : B resistance After 1008h 4.5E+8 Ω (85, 85%RH) Migration test No migration JIS Z 3197 8.5.4 1
A.Special characteristic 1.Electrolytic corrosion Outline An electrolytic corrosion happens at the point of soldering because difference metals, base metal or alloy of solder contact. The electrolytic corrosion happens by the difference of metal s electrode potential composed of metal alloy, the lower metal of electrode potential is dissolved as anode and metal alloy are peeled off. So R23 (Sn-3.0Cu), metal components of R23-C601-3, shall be measured electrolytic corrosion characteristic and compared with K4 (Sn-3.5Ag-0.2Ni) of Pb free solder for Al and 18Sn-2.0Ag-Pb that is Pb solder for Al. Test method (Our company method) 2 Al plates (5mm 30mm) shall be soldered with flux for Al and 30g metal sample. The test specimen shall be soaked in 40 artificial sea water and kept in this state. Measuring time shall be taken to erode the point of soldering and separate each Al plate. Test metal specimens are as follows, A R23( Sn-3.0Cu) B K4( Sn-3.5Ag-0.2Ni) C 18Sn-2.0Ag-Pb 2.Washability of flux residue Outline It is important to wash flux residue for prevention of corrosion and insulation reliability assurance for a long time. About R23-C601-3, the flux residue is hygroscopic property, so there is ionic material in the flux residue, it needs to wash. So we shall show the method of washing of R23-C601-3 and the reliability after washing, and evaluate the ionic residue value and the corrosion after washing and no washing. 2-1 Ionic residue Test method (Our company method) Test board, specified in JIS, shall be soldered by R23-C601-3 with soldering iron of 380 and washed by ion exchanged water, the specific resistance is more than 5000Ωm at 20, three times that is three, one and one with ultrasonic washer. The ionexchanged water shall be changed and the board shall be rinsed every washing. After washing the board shall be dried in drying machine by blow adjusted 80 for 5 minutes. Test method (Based on JIS Z 3197 8.5.2) 18 pieces of test boards shall be prepared, the half, 9 boards shall be soldered and washed as above method, the other 9 boards not soldered as blank. Each 9 boards shall be measured the Ionic residue value by Omega Meter. As comparison, no washing test boards shall be done, too. Ionic residue value is less than 14µg NaCl/in 2 enlarged Initial enlarged crack Before washing After washing Erosion characteristic of R23 (Sn-3.0Cu) at the surface between Al and solder is not better than K4 (Sn-3.5Ag-0.2Ni) and 18Sn-2.0Ag-Pb. Table2. Electrolytic corrosion sample time R23 96h K4 3096h 18Sn-2.0Ag-Pb 504h sample R23-C601-3 Table3. Ionic residue value washing Ionic residue value (µg NaCl/in 2 ) washing 1.0 no washing more than 50 s showed that the flux residue was able to be washed by water with ultrasonic washer and in the case of no-washing, much ionic material remained. 2
2-2 Corrosion Test method (Based on JIS Z 3197 8.4.1) The swirled sample R23-C601-3 shall be melted at the center of Cu plate been finished preparation for 5 seconds after it begins to melt. After that the test piece shall be got cold at room temperature, and washed and dried in the washing method shown in 2-1. It shall be put in thermoregulator adjusted 40±2,90~95% and kept in this state for 96 hours. 96 hours later corrosion shall be observed. As comparison, no washing and Al plate shall be done, too. Washed Cu and Al plates were not found corrosion, but no washed plates were found corrosion at soldered portion and the base. Initial 96 hours later 3.Solderability Outline Al has more strong oxide film on the surface than Cu or other base metals, so the solderability is not good. And in the case that Al is coated any organic substances, for example the heat resistance is high, even if it is thermoplasticity, it is difficult to solder with just heating. So some strong activator is needed to remove it. R23-C601-3 is good at the solderability for Al and removing the organic substance, that is high heat resistance, coated Al. We shall show the solderability of R23-C601-3 and compare of general Pb free solder as follows. Test method (Our company method) Copper plate covered with Al urethane wire shall be soldered with R23-C601-3.Temperature of soldering iron is 380. And J3-STE-3, Pb free solder contain fluorine in our company, shall be done, too. R23-C601-3 J3-STE-3 Fig. washing 96h later Point of corrosion Note: 1solder 2Cu plate Fig. no washing 3
B.Basic characteristic 1.Solder alloy 1.1:Alloy composition Table4. Alloy composition Sn Pb Cu Bi Sb Barance less than 0.05 1.2:Melting point 3.0±0.3 Table5. Melting point Solidus temperature( ) 227 Liquidus temperature( ) 312 2.Flux content Test method (Based on JIS Z 3197 8.1.2) 30±1g W 1, the resin cored of solder shall be heated by burner in crucible. After solder and flux shall be separated completely, the solder shall be solidified and cleaned, dried, and measured W2. The flux content shall be calculated by the following formula. Flux content(%) = (W1 -W2) 100 / W1 Flux content shall be 3.0±0.3 (%) 0.10 Table6. Flux content Flux content(%) 3.0 0.10 Zn Fe Al As Cd 0.001 0.02 0.001 0.03 less than 0.002 3.Halide content Test method (Based on JIS Z 3197 8.1.4.2.1) 5.0±0.1g flux shall be put into 300ml beaker and dissolved with ion exchanged water. The solution shall be titrated by silver nitrate standard solution with electric titration equipment. Halide content shall be 0% Fluorine content shall be 20±3% Table7. Halide content Halide content(%) 0 Fluorine content (%) 20 4.Expansion Test method (Based on JIS Z 3197 8.3.1.1) The one side of Cu plate (30 30 0.3mm) shall be polished by abrasive paper (No.1000) in alcohol and cleaned with alcohol, and dried at room temperature. These plates shall be put into a dryer adjusted 150±3 for 1 hour to produce uniform oxidate on the plates. Al plate (30 30 0.5mm) shall be not pretreated like copper plate. Swirled 0.30±0.03g resin flux cored of solder shall be placed at the center of Cu (Al) plate. It shall be melted on a solder bath adjusted 270 for 30 seconds after starting to melt, and lifted from the bath and cooled at room temperature. Flux residue shall be removed. The height of the spread solder shall be measured by a micrometer and calculated by the following method. Cu :75% min.,al :70% min. S:Spreading ratio(%) H:height of the spread solder (mm) D:diameter of the solder, when it is assumed to be a sphere (mm) D: = 1.24V 1/3 V:density of solder Table8. Spreading ratio Spreading ratio (%) Cu 77.4 Al 75.3 note:diameter of solder is φ0.8 mm 4
5.Insulation resistance Test method (Based on JIS Z 3197 8.5.3) The test board specified JIS shall be soldered with a soldering iron (380 ) and cleaned by ion exchanged water. It shall be dried in a drying machine adjusted 80 for 5 minutes. It shall be put into a thermoregulator adjusted 85 85%, and initial, 24, 96, 168, 408, 648, 840, 1008 hours later, the insulation resistance shall be measured at DC100V. s are showed as follows. Table9. Insulation resistance (Ω) Initial 24hr 96hr 168hr No.1 2.3E+13 1.1E+8 1.5E+8 1.8E+8 No.2 6.5E+13 2.6E+8 3.3E+8 3.5E+8 No.3 7.0E+13 3.0E+8 4.1E+8 4.5E+8 Average 4.7E+13 2.0E+8 2.8E+8 3.0E+8 408hr 648hr 840hr 1008hr No.1 2.0E+8 2.1E+8 2.3E+8 2.4E+8 No.2 4.0E+8 4.6E+8 5.1E+8 5.6E+8 No.3 5.3E+8 5.7E+8 6.2E+8 6.6E+8 Average 3.5E+8 3.8E+8 4.2E+8 4.5E+8 6.Voltage-applied moisture resistance (Migration test) Test method (Based on JIS Z 3197 8.5.4) The test board specified JIS is soldered with a soldering iron (380 ) and cleaned by ion exchanged water. It shall be dried in a drying machine adjusted 8 0 for 5 minutes. It shall be put into a thermoregulator adjusted 85 85%, DC45 to 50V shall be applied between the electrodes, and initial, 24, 96, 168, 408, 648, 840, 1008 hours later, the insulation resistance shall be measured at DC100V. 1008h later the test boards shall be taken out and confirmed that if there shall be any migration. Any migration were not found. Table10. Voltage-applied resistance (Ω) Initial 24hr 96hr 168hr No.1 5.0E+12 1.0E+8 1.1E+8 2.1E+8 No.2 3.5E+13 4.4E+8 5.0E+8 6.9E+8 No.3 2.6E+13 3.1E+8 3.8E+8 5.0E+8 Average 1.7E+13 2.6E+8 2.8E+8 4.2E+8 408hr 648hr 840hr 1008hr No.1 5.3E+8 6.8E+8 7.5E+8 8.1E+8 No.2 9.5E+8 9.6E+8 1.2E+9 1.2E+9 No.3 7.9E+8 9.6E+8 1.1E+9 1.0E+9 Average 7.4E+8 8.6E+8 9.8E+8 9.8E+8 1.0E+14 insulation resistance(ω) 1.0E+13 1.0E+12 1.0E+11 1.0E+10 1.0E+09 1.0E+08 1.0E+07 0 500 Time(h) 1000 Fig. Insulation resistance test Insulation resistance (Ω) 1.0E+14 1.0E+13 1.0E+12 1.0E+11 1.0E+10 1.0E+09 1.0E+08 1.0E+07 0 500 Time (h) 1000 Fig. Voltage-applied resistance test 5