本文選題：鋁合金 + 鈍化　； 參考：《沈陽理工大學(xué)》2017年碩士論文

【摘要】：鋁及鋁合金是目前工業(yè)上應(yīng)用較為廣泛的輕金屬,由于其儲量大、來源廣、熔點高、具有很好的延展性,因此在汽車工件、飛機機身等機械工業(yè)領(lǐng)域有大量需求。鋁合金具有很高的塑性,可被加工成各種板材、型材、鑄件應(yīng)用在工業(yè)生產(chǎn)中。鋁合金本身能夠與氧氣接觸形成一層防止腐蝕的氧化膜,但在工業(yè)和大氣環(huán)境中酸性物質(zhì)、鹽類物質(zhì)的侵蝕程度較強,而自身氧化膜遠遠不能夠滿足防腐蝕的需要,在生產(chǎn)中腐蝕會造成嚴重的經(jīng)濟損失和安全隱患,因此鋁及鋁合金的防腐研究越來越受到人們的重視。以高效、綠色環(huán)保、簡化工藝為目標,對目前存在的鋯酸鹽、稀土鹽、鉬酸鹽、有機物等幾類鈍化體系比較優(yōu)劣,篩選出氟鋯酸鉀鈍化體系。氟鋯酸鉀及強氧化物組成的鈍化體系具有較強的氧化性,膜層的耐腐蝕性能較好,但鈍化液不穩(wěn)定。因此以氟鋯酸鉀為主要成膜物質(zhì),研究使用添加劑來替代強氧化物,使得膜層耐蝕性能提升,并制備出穩(wěn)定可重復(fù)使用的的鈍化液。首先通過鋁合金耐鹽霧腐蝕實驗和電化學(xué)極化測試的單因素試驗確定氟鋯酸鉀的含量為2.0g/L,并優(yōu)化其鈍化工藝得到鈍化時間7min,溫度25℃,pH值3.2的鈍化條件。在此基礎(chǔ)上研究添加劑Mn(NO_3)_2和LaCl_3對膜層耐蝕性能提高的作用。確定了Mn(NO_3)_2濃度為2.4g/L時,其氧化性可使鋁合金的耐蝕性能提高,達到87小時。LaCl3在0.3g/L時可促進成膜過程,使得鈍化膜更加致密,耐蝕性能提高20%,達103小時。樹脂作為有機物有很好的封閉作用和疏水性,能夠?qū)︿X合金起到防護作用,因此本文還研究了以氟鋯酸鉀-樹脂為主要成膜物質(zhì)的無機-有機復(fù)合鈍化體系。在單獨氟鋯酸鉀最優(yōu)鈍化工藝的基礎(chǔ)上,通過單因素實驗確定復(fù)合體系鈍化液配方,通過正交試驗優(yōu)化得到樹脂的量為10g/L,添加偏釩酸鈉1.0g/L、硅烷3ml/L,固化條件為:80℃,60min。此鈍化體系及工藝可使鋁合金耐鹽霧腐蝕時間大大提高,達138小時,復(fù)合膜層的疏水性有所提高,附著力可達1級。并通過SEM及EDS研究了膜層的微觀形貌以及膜層的元素組成分析成膜過程。
[Abstract]:Aluminum and aluminum alloys are widely used in industry at present. Because of their large reserves, wide sources, high melting point and good ductility, aluminum and aluminum alloys have a large demand in the field of mechanical industry such as automobile parts, aircraft fuselage and so on. Aluminum alloy has high plasticity, can be processed into various plates, profiles, castings used in industrial production. Aluminum alloy itself can contact with oxygen to form a corrosion resistant oxide film, but in the industrial and atmospheric environment, the corrosion degree of acid substances, salt substances is relatively strong, and its own oxide film is far from meeting the need of corrosion prevention. Corrosion in production will cause serious economic losses and safety risks, so people pay more and more attention to the corrosion protection of aluminum and aluminum alloys. Aiming at high efficiency, green environmental protection and simplified technology, the passivation system of potassium zirconate, potassium zirconate, molybdate, organic compound and so on was selected. The passivation system was compared with that of zirconate, rare earth salt, molybdate and organic matter. The passivation system composed of potassium fluoride zirconate and strong oxides has strong oxidation property and good corrosion resistance, but the passivation solution is unstable. Therefore, using potassium zirconate as the main film-forming material, the additive was used to replace the strong oxide to improve the corrosion resistance of the film, and a stable and reusable passivation solution was prepared. Firstly, the content of potassium zirconate was determined to be 2.0 g / L by single factor test of salt spray corrosion resistance and electrochemical polarization test of aluminum alloy, and the passivation conditions of passivation time of 7 min and pH value of 3.2 at 25 鈩，

本文編號：1823343