發(fā)布時間：2018-03-14 06:37

  本文選題：復合鍍層　切入點：納米顆粒　出處：《中國石油大學(華東)》2015年碩士論文　論文類型：學位論文

【摘要】：電沉積技術經過幾十年的發(fā)展,即滿足了裝飾上的需要,也對材料表面進行保護作用,成為工業(yè)上不可缺少的技術手段。近年來,由于復合電沉積技術制備的鍍層具有優(yōu)異的力學、熱學、光學及電磁學性能,以及耐腐蝕、硬度高、抗高溫氧化和耐磨等性能,所以,復合鍍層成為研究的熱點,引起了人們的普遍關注。本論文結合相關的研究,以Ni-W為基體金屬制備含有LaCl_3、Al_2O_3的復合鍍層,采用SEM、XRD等分析手段,確定復合鍍層的最佳工藝條件,考察了工藝參數(shù)對復合鍍層的影響;制備Ni-W/LaCl_3復合鍍層,研究復合鍍層的結構和耐腐蝕性能;制備Ni-W/LaCl_3-Al_2O_3復合鍍層,并研究其高溫氧化性能;分析了Ni-W、Ni-W/LaCl_3、Ni-W/Al_2O_3、Ni-W/LaCl_3-Al_2O_3不同鍍層的耐腐蝕性能。具體的研究內容如下:通過設計正交實驗確定Ni-W電沉積的優(yōu)化參數(shù),在此基礎上,研究了單個的工藝參數(shù)對復合鍍層性能的影響。結果表明,優(yōu)化工藝為:硫酸鎳50g/L,鎢酸鈉60g/L,檸檬酸鈉100g/L,次亞磷酸鈉40g/L,pH值為9,電流密度為40mA/cm2,溫度為60℃。最佳工藝條件下,復合鍍層更均勻平整,具有良好的硬度,耐高溫、耐腐蝕性能;隨著電流密度和電鍍時間的增加,Ni-W鍍層的硬度呈現(xiàn)先增大,后減小的變化規(guī)律。在優(yōu)化的工藝條件下,研究添加稀土化合物LaCl_3制備Ni-W/LaCl_3復合鍍層,結果發(fā)現(xiàn):稀土化合物LaCl_3的最佳濃度為1g/L,此濃度下的Ni-W/LaCl_3復合鍍層具有最大的厚度;比Ni-W鍍層的表面致密,耐腐蝕性好。在Ni-W/LaCl_3復合鍍層的基礎上,制備和研究Ni-W/Al_2O_3-LaCl_3復合鍍層,確定了Al_2O_3納米粒子的最佳含量為20g/L;通過熱處理的手段,進行高溫氧化實驗,采用XRD和SEM分析納米粒子含量、氧化溫度對氧化前后的復合鍍層組的組織結構和表面形貌的影響。納米粒子的加入提高了鍍層硬度,細化晶粒;經過800℃,120min熱處理之后,Ni-W/Al_2O_3-LaCl_3復合鍍層比Ni-W/La Cl_3復合鍍層氧化增重低42%,Al_2O_3納米粒子可以提高鍍層的抗高溫氧化性能,但沒有改變鍍層的氧化機制。鍍層600℃以前仍具有較好的性能,高溫氧化以后,鍍層由非晶態(tài)轉變?yōu)榫B(tài)。最后采用電化學工作站測定了Ni-W、Ni-W/LaCl_3、Ni-W/Al_2O_3、Ni-W/LaCl_3-Al_2O_3鍍層在3.5%NaCl溶液中的極化曲線和交流阻抗譜。結果表明:Al_2O_3納米顆粒和稀土化合物LaCl_3的加入優(yōu)化了鍍層的表面形態(tài),提高了鍍層的致密性,提高了復合鍍層的耐腐蝕性能;比較Ni-W、Ni-W/LaCl_3復合鍍層、Ni-W/Al_2O_3復合鍍層,Ni-W/LaCl_3-Al_2O_3復合鍍層的耐蝕性,結果發(fā)現(xiàn)Ni-W/LaCl_3-Al_2O_3復合鍍層具有最好的耐腐蝕性能。
[Abstract]:After decades of development, electrodeposition technology has met the need of decoration and protected the surface of materials. It has become an indispensable technical means in industry in recent years. Because of the excellent mechanical, thermal, optical and electromagnetic properties, corrosion resistance, high hardness, high temperature oxidation resistance and wear resistance, the composite coating has become a hot research topic, because of its excellent mechanical, thermal, optical and electromagnetic properties, such as high temperature oxidation resistance, high hardness, high temperature oxidation resistance and wear resistance. In this paper, the composite coating containing LaClS3Al2O3 was prepared with Ni-W as the base metal, and the optimum technological conditions of the composite coating were determined by means of SEM, XRD and other analytical methods. The influence of process parameters on the composite coating was investigated, the structure and corrosion resistance of the composite coating were studied by preparing Ni-W/LaCl_3 composite coating, and the oxidation performance of Ni-W/LaCl_3-Al_2O_3 composite coating at high temperature was studied. The corrosion resistance of Ni-WN / LaCl3-Al2O3 coating is analyzed. The specific contents are as follows: the optimum parameters of Ni-W electrodeposition are determined by orthogonal design. On this basis, the effects of single process parameters on the properties of composite coatings are studied. The optimized process is: nickel sulfate 50 g / L, sodium tungstate 60 g / L, sodium citrate 100 g / L, sodium hypophosphite 40 g / L, pH 9, current density 40 Ma / cm 2, temperature 60 鈩，

本文編號：1610083