本文關(guān)鍵詞： 鈦及鈦合金 磷酸鹽 轉(zhuǎn)化膜 納米氮化硅 后處理方式　出處：《山東大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：磷酸鋅轉(zhuǎn)化膜廣泛應(yīng)用于金屬表面的防腐、提高涂裝層結(jié)合力和表面潤滑等方面。同時(shí),鈦因具有高比強(qiáng)度、無磁性、穩(wěn)定性好等許多優(yōu)異性能而在國民經(jīng)濟(jì)中的作用越來越大。但鈦表面由于存在易氧化、對(duì)黏著磨損敏感、對(duì)涂層附著力差等缺陷而限制了其應(yīng)用。本文利用易于實(shí)現(xiàn)的常溫化學(xué)轉(zhuǎn)化方法在鈦(TA2)表面制備磷酸鋅轉(zhuǎn)化膜。通過討論前處理工藝、基礎(chǔ)轉(zhuǎn)化工藝參數(shù)和后處理工藝等因素,并通過添加納米Si_3N_4顆粒,確定了一種在常溫條件下在鈦表面制備納米復(fù)合磷酸鹽轉(zhuǎn)化膜的工藝配方。分別利用X射線衍射(XRD)、場發(fā)射掃描電子顯微鏡(FE-SEM)、聲發(fā)射劃痕儀及三電極電化學(xué)工作站等手段對(duì)轉(zhuǎn)化膜的物相、微觀形貌、力學(xué)性能及耐蝕性能進(jìn)行了系統(tǒng)的表征和分析。結(jié)果表明,轉(zhuǎn)化膜主要有四水磷酸鋅(Zn3(P04)2·4H20)組成,工藝條件對(duì)轉(zhuǎn)化膜物相種類影響不大。堿洗除油、酸洗和表調(diào)對(duì)轉(zhuǎn)化膜的影響是互相不可替代的,是制備完整的高質(zhì)量轉(zhuǎn)化膜的前提。轉(zhuǎn)化時(shí)間和轉(zhuǎn)化溫度對(duì)轉(zhuǎn)化膜物相影響較小,在25℃和75℃溫度分別制備的轉(zhuǎn)化膜膜厚相差較大,而結(jié)合力和耐腐蝕性能相差不大。在0.5-10 min內(nèi),隨著轉(zhuǎn)化時(shí)間延長,轉(zhuǎn)化膜晶粒尺寸變大,數(shù)量增加,晶粒形狀由單一薄片狀向粗糙板條狀變化,逐漸形成致密和均勻的轉(zhuǎn)化膜。不同清洗干燥次序?qū)瘜W(xué)轉(zhuǎn)化膜的微觀形貌及耐腐蝕性能有明顯的影響,先干后洗制備的轉(zhuǎn)化膜,在干燥過程中殘留轉(zhuǎn)化液的析出相填充了晶粒間隙,提高了致密度,析出相覆蓋晶粒表面使得晶粒顯得細(xì)小,進(jìn)一步提高了膜層的耐蝕性能,同時(shí)形成多孔結(jié)構(gòu),有助于改善鈦及鈦合金涂裝性能。在轉(zhuǎn)化膜中引入納米硬質(zhì)顆粒不改變轉(zhuǎn)化膜原有的物相,其本身在轉(zhuǎn)化過程中也不發(fā)生物相變化。納米Si_3N_4顆粒多數(shù)團(tuán)聚在轉(zhuǎn)化膜中的磷酸鋅晶粒之間的凹槽或者空隙中,有些鑲嵌在晶粒側(cè)面,有些附著在裸露基體上,推測鑲嵌在晶粒側(cè)面和附著在裸露基體上的納米Si_3N_4顆粒有可能作為形核中心促進(jìn)轉(zhuǎn)化膜形核和生長。當(dāng)摻雜量在0.5-2.0g/L之間時(shí),磷酸鋅生成量隨著納米Si_3N_4摻雜量增加而增多,晶粒尺寸先增大后減小,轉(zhuǎn)化膜厚度有增大的趨勢,在本文對(duì)比參數(shù)中當(dāng)Si_3N_4摻雜量為0.5g/L時(shí),晶粒尺寸最小,約10μm。在轉(zhuǎn)化液中添加納米Si_3N_4顆粒會(huì)改善轉(zhuǎn)化膜的耐腐蝕性能,隨著摻雜量增大,腐蝕電壓先變大后減小,腐蝕電流先減小后增大。另外,電化學(xué)工作站檢測后,在殘留轉(zhuǎn)化膜中可以檢測到Si_3N_4,說明在內(nèi)部晶粒之間甚至晶粒內(nèi)部也可能含有納米Si_3N_4顆粒。轉(zhuǎn)化液中添加納米Si_3N_4顆粒會(huì)改善轉(zhuǎn)化膜與基體的結(jié)合力。
[Abstract]:Zinc phosphate conversion film is widely used in anticorrosion of metal surface, improving adhesion of coating layer and surface lubrication. At the same time, titanium has high specific strength and no magnetic properties. Many excellent properties such as good stability are playing a more and more important role in the national economy, but the titanium surface is sensitive to adhesive wear because of its easy oxidation. In this paper, zinc phosphate conversion film was prepared on the surface of titanium tetra (TA2) by using the easily realized chemical conversion method at room temperature, and the pretreatment process was discussed. Basic conversion process parameters and post-treatment process factors, and through the addition of nanometer Si_3N_4 particles. A formula for preparing nano-composite phosphate conversion film on titanium surface at room temperature was established. X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM) were used. The phase, microstructure, mechanical properties and corrosion resistance of the conversion film were systematically characterized and analyzed by means of acoustic emission scratch tester and three-electrode electrochemical workstation. The conversion film is mainly composed of zinc phosphate tetrahydrate Zn3P04P044H20), and the technological conditions have little effect on the kinds of phase of the conversion membrane. The influence of acid pickling and surface modulation on the conversion film is irreplaceable and is the premise of preparing the complete high quality conversion film. The transformation time and temperature have little effect on the phase of the conversion film. The thickness of the conversion film prepared at 25 鈩，

本文編號(hào)：1484307