Cov khoom ntawm txhuas - tin alloys

Cov hlau lead tseem ceeb tshaj plaws - raws li alloys yog cov hmoov txhuas - tin alloys. Cov hlau no muaj lub teeb grey metallic luster, yog softer, thiab muaj ib tug qis porosity tshaj ib txheej ntawm txhuas los yog tin. Cov txheej txheem electrode muaj peev xwm sib txawv ntawm cov hlau lead thiab cov tin tsuas yog 10mV, thiab cov overpotential ntawm hydrogen yog siab, yog li nws tuaj yeem yog co - precipitated nyob rau hauv ib qho yooj yim muaj zog acid plating tov. Nws tsuas yog yuav tsum tau tswj cov concentration piv ntawm cov hlau lead thiab tin ions thiab qhov ceev tam sim no kom tau txais cov khoom sib xyaw alloy. Alloy plating, nws tam sim no efficiency yog ze rau 100 %.

Pb - tin alloy plating tov, ntxiv rau feem ntau siv fluoroborate plating tov, sulfamate, phenolsulfonate, alkanolsulfonate thiab citrate plating tov tau siv nyob rau hauv ntau lawm.

Lub metallographic qauv ntawm txhuas - tin alloy yog supersaturated khoom tov, tab sis theem transformation yuav maj mam tshwm sim thaum lub sij hawm cia. Hauv qee qhov tshwj xeeb, cov khoom tseem yuav tsim cov sib txuas sib txuas nrog cov substrate, xws li tin thiab tooj liab. Thaum tus yam ntxwv no muaj cov cai tshwj xeeb, cov txheej txheem kev sib cais nruab nrab yuav tsum tau ntxiv ntawm cov substrate thiab cov hlau lead - tin alloy plating txheej.

Lub melting point ntawm tin - txhuas alloy yog qis dua cov ntshiab tin thiab ntshiab txhuas, thiab nws cov zoo zoo yog tias nws cov porosity thiab solderability yog zoo dua li ntawm ib cov hlau. Yog tias cov txheej txheej ntshiab tin tau muab tso rau lub sijhawm ntev, koob - zoo li cov muaju (tin whiskers) yuav loj tuaj rau ntawm qhov chaw, uas tuaj yeem ua rau luv luv; nws kuj tuaj yeem tsim" tin plague" ntawm qhov kub thiab txias. Yog 2% rau 3% ntawm txhuas yog ntxiv rau cov tin ntshiab, qhov tshwm sim no tsis yooj yim tshwm sim. Yog li ntawd, txheej txheej no yog qhov tseem ceeb tshaj plaws ntawm cov txheej txheem solderability hauv cov khoom siv hluav taws xob.

Lead - tin alloys nrog cov ntsiab lus sib txawv tin muaj cov khoom sib txawv thiab siv. Feem ntau, kev siv ntau yam txhuas - tin alloys yog txiav txim siab raws li qhov sib txawv ntawm cov alloys uas lawv muaj.

Cov muaj pes tsawg leeg ntawm txhuas thiab tin ntawm qhov qis tshaj eutectic point (183 degree) yog 61.9 % tin thiab 38.1% coj. Lub sijhawm no, cov alloy muaj qhov zoo tshaj plaws vuam lub zog thiab wetting muaj peev xwm. Yog li ntawd, feem ntau ntawm cov tam sim no solder thiab vuam txheej siv 60 % tin thiab 40% coj. Alloy txheej.