本文選題：TC4鈦合金　切入點：電鍍　出處：《蘭州理工大學》2017年碩士論文　論文類型：學位論文

【摘要】：鈦合金因其密度小、比強度高、耐蝕性及生物相溶性好等特點受到人們的青睞,使其在汽車、醫(yī)療器械及航空航天國防事業(yè)中得到了廣泛應用。然而,鈦合金表面硬度低,易氧化的特點使鈦合金在工業(yè)應用中表現出較差的耐磨性,大大限制了其應用范圍,因此對鈦合金表面進行改性處理就顯得尤為重要。Ni-P鍍層因其簡單的操作工藝和良好的耐磨耐蝕性等特點常被用于金屬表面的改性處理,本文擬采用電鍍Ni-P鍍層的方法對TC4鈦合金表面進行改性處理,提高鈦合金的表面性能。通過對電鍍鎳磷制備工藝及研究現狀的總結,在次磷酸-鎳鹽體系中對TC4鈦合金電鍍Ni-P工藝進行了研究,通過設計正交試驗對工藝配方和參數進行了優(yōu)化,獲得的最佳工藝配方為:NiSO_4·6H_2O 140g/L、電流密度4A/dm2、pH值3.5、NiCl_2·6H_2O 16g/L、溫度65℃、NaH_2PO_2·H_2O 8g/L、H_3PO_4 35g/L。TC4鈦合金在該工藝條件下電鍍Ni-P鍍層,不僅鍍速快硬度高,而且獲得的鍍層表面光亮平整、致密度高。在正交試驗的基礎上,采用單因素實驗,研究了各工藝參數對Ni-P鍍層沉積速度、硬度及磷含量的影響規(guī)律。為了改善鈦合金表面Ni-P鍍層的性能,對鈦合金表面預處理工藝進行了研究。通過對不同預處理工藝下獲得的鍍層的表面形貌、硬度和結合強度的對比分析,確定了最佳預處理工藝:打磨→化學除油→酸洗活化→化學預鍍。對鍍層的微觀形貌、物相組成、硬度及耐磨耐蝕性進行了研究分析,結果表明:鍍層表面呈均勻分布的胞狀結構,表面致密光滑,主要成分為Ni和P;隨著熱處理溫度的升高,鍍層結構由非晶態(tài)逐漸轉化為晶態(tài),熱處理溫度在400℃時,鍍層中有Ni_3P相析出;鍍層的硬度與P含量和熱處理溫度有關,鍍層硬度隨著P含量的增加呈現先增大后減小的趨勢,當P含量在8%時鍍層硬度有最大值;鍍層硬度隨熱處理溫度的升高先增加后減小,經過400℃熱處理后鍍層硬度達到最大;鍍層經400℃熱處理后耐磨耐蝕性顯著增強。
[Abstract]:Because of its low density, high specific strength, corrosion resistance and good biocompatibility, titanium alloy has been widely used in automobile, medical device and aerospace industry. However, the surface hardness of titanium alloy is low. The characteristic of easy oxidation makes titanium alloy exhibit poor wear resistance in industrial application, which greatly limits its application scope. Therefore, it is very important to modify titanium alloy surface. Ni-P coating is often used to modify metal surface because of its simple operation technology and good wear resistance and corrosion resistance. In this paper, the surface of TC4 titanium alloy is modified by electroplating of Ni-P coating to improve the surface properties of titanium alloy. The TC4 titanium alloy electroplating Ni-P process was studied in the system of hypophosphoric acid and nickel salt. The formulation and parameters of the process were optimized by designing orthogonal test. The best technological formula obtained is: 1: NiSOS 4 路6H _ 2O 140 g / L, current density 4 A / m ~ (2 / 2) pH 3.5 / NiCl _ 2 路6H _ 2O 16 g / L, temperature 65 鈩，

本文編號：1636117