ALIAJE ECOLOGICE PE BAZA DE STANIU PENTRU APLICATII IN INDUSTRIA ELECTROTEHNICA

Autor/autori: Dr. ing. Magdalena LUNGU, Ing. Nicolae STANCU, Dr. ing. Violeta TSAKIRIS, Fiz. Lucia LEONAT, Chim. Alexandra BRATULESCU, Fiz. Delia PATROI, Sorina MITREA, Mihai IORDOC, Aristofan TEISANU

Rezumat: Lucrarea prezinta rezultatele cercetarilor privind obtinerea prin turnare a unor aliaje ecologice de tip Sn-Bi-Sb pentru lipire moale in vederea inlocuirii unor aliaje toxice, cum ar fi cele din Sn-Pb 60-40 utilizate pana de curand. Folosirea Pb sau a materialelor care contin Pb este deja interzisa sau restrictionata in unele tari pentru numeroase aplicatii. De aceea, a aparut necesitatea de a se inlocui Pb folosit ca element de aliere in aliajele de lipire utilizate in industria electrotehnica. In cadrul lucrarilor de cercetare desfasurate, aliajele din Sn-Bi- Sb s-au elaborat prin topire intr-un cuptor electric cu inductie sau intr-un cuptor de tratament termic, pornind fie de la amestecuri de pulberi microcristaline pure din Sn, Bi si Sb, omogenizate mecanic si presate cu un grad de compactare de 80 %, fie de la Sn pur sub forma de picaturi metalice obtinute prin topire, amestecate cu un prealiaj din Bi-Sb, in proportiile gravimetrice stabilite. Aliajele Sn-Bi-Sb au fost caracterizate din punctul de vedere al proprietatilor fizice, electrice, termice, mecanice si electrochimice. Noile aliaje ecologice din Sn-Bi-Sb prezinta unele caracteristici tehnice imbunatatite fata de cele ale aliajelor traditionale Sn-Pb.

Cuvinte cheie: aliaje de staniu fara plumb, lipire moale.

Abstract: The paper presents the research results concerning the obtaining by casting of some ecological alloys of Sn-Bi-Sb for soft soldering in order to replace some toxic alloys, such as Sn-Pb 60-40 used up to now. Using Pb or Pb-containing materials is already prohibited or restricted in some countries for many applications. Therefore, it was necessary to replace the Pb used as an alloying element in solder alloys from electrical engineering industry. In the developed research works, the Sn-Bi-Sb alloys were obtained by melting in an electric induction oven or in a heat treatment oven, starting either from mixtures of pure Sn, Bi and Sb microcrystalline powders, mechanically homogenized and pressed with a degree of compaction of 80 % or from pure Sn metal drops produced by melting, mixed with a Bi-Sb prealloy in the established gravimetric proportions. The Sn-Bi-Sb alloys were characterized from the physical, electrical, thermal, mechanical and electrochemical properties point of view. The new Sn-Bi-Sb ecological alloys have some technical characteristics improved over those of traditional Sn-Pb alloys.

Keywords: lead-free tin alloys, soft soldering.

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