【摘要】：鈀鎳(Pd-Ni)合金由于其相對較低的成本與優(yōu)異的綜合性能,在裝飾,電接觸材料,電催化,有機合成等領(lǐng)域被廣泛研究與應(yīng)用。本文首先開發(fā)了 Pd-Ni合金膜電鍍工藝,在其基礎(chǔ)上,通過電鍍的方式分別在316L不銹鋼表面制備了 Pd-Ni/TiO2復(fù)合鍍層與Pd-Ni-W三元合金鍍層兩種鍍層。主要通過電化學(xué)方法研究了鍍層的耐蝕性能與機理。通過XRD、SEM、EDS、GODES等方法對鍍層的形貌和結(jié)構(gòu)進行表征,并且討論了其與耐蝕性能之間的關(guān)系。具體研究如下:(1)在316L不銹鋼表面,通過直流電鍍的方法分別制備了 Pd-Ni合金鍍層與Pd-Ni/TiO2復(fù)合鍍層鍍。電化學(xué)測試結(jié)果表明:Pd-Ni/TiO2復(fù)合鍍層在60℃的20%硫酸溶液中電流密度更小,交流阻抗容抗弧半徑更大。XRD測試表明復(fù)合鍍層的晶粒尺寸相比合金鍍層的更小。通過SEM觀察兩種鍍層的微觀形貌,發(fā)現(xiàn)在電鍍液中加入5 g/L納米TiO2顆粒后獲得的鍍層形貌明顯不同。(2)在直流電鍍的基礎(chǔ)上,采用單因素變量法研究了電鍍脈沖工藝參數(shù)對Pd-Ni/TiO2復(fù)合鍍層電化學(xué)性能的影響。包括:電流密度,占空比,頻率和電鍍溫度。結(jié)果表明:Pd-Ni/TiO2復(fù)合鍍層最佳的工藝為:電流密度1 A/dm2,占空比0.8,頻率1 Hz和電鍍溫度 40℃。(3)著重研究了電鍍液中不同納米TiO2含量對所獲得鍍層的結(jié)構(gòu)與性能的影響。通過XRD測試發(fā)現(xiàn),TiO2的加入能夠起到細化晶粒的作用,并且加入量越多,鍍層晶粒尺寸越小。通過SEM結(jié)果發(fā)現(xiàn),TiO2的加入能夠修飾鍍層表面的形貌。加入量過大時,在鍍層表面觀測到了TiO2顆粒團聚現(xiàn)象。EDS與GDOES結(jié)果表明,TiO2顆粒的加入還會影響鍍層成分的變化。鍍液中TiO2顆粒越多,鍍層中Pd含量降低,Ni含量反而上升。此外,GDOES測試結(jié)果還表明復(fù)合鍍層中的TiO2顆粒并不是存在于整個鍍層的。電化學(xué)測試結(jié)果表明:5g/LTiO2顆粒鍍液中獲得的復(fù)合鍍層耐蝕性最好。然而隨著鍍液中TiO2顆粒含量繼續(xù)增加其耐蝕性反而下降。(4)開發(fā)了 Pd-Ni-W三元合金電鍍工藝,獲得了不同W含量的鍍層,由于元素W的存在,所得鍍層晶粒得到細化。此結(jié)果由XRD與陰極極化曲線得到驗證。隨著電鍍液中W含量的增加,所得鍍層的Ni含量增加,同時Pd含量隨之減少。適量W的添加到Pd-Ni電鍍液,從其中得到的Pd-Ni-W三元合金鍍層在熱硫酸溶液中的耐蝕性會稍有提升。鍍層中W含量的增加對于鍍層的硬度增加是有利的。Pd-Ni-W合金鍍層試樣在氣液沖擊環(huán)境下沒有機械損傷,但試樣的電化學(xué)腐蝕速率加快。
[Abstract]:PD-Ni (Pd-Ni) alloys have been widely studied and applied in decoration, electrical contact materials, electrocatalysis, organic synthesis and other fields because of their relatively low cost and excellent comprehensive properties. In this paper, the electroplating process of Pd-Ni alloy film was developed. On the basis of it, Pd-Ni/TiO2 composite coating and Pd-Ni-W ternary alloy coating were prepared on 316L stainless steel surface by electroplating. The corrosion resistance and mechanism of the coating were studied by electrochemical method. The morphology and structure of the coating were characterized by XRD,SEM,EDS,GODES, and the relationship between the morphology and corrosion resistance of the coating was discussed. The specific research is as follows: (1) Pd-Ni alloy coating and Pd-Ni/TiO2 composite coating were prepared by DC plating on 316L stainless steel surface. The electrochemical test results show that the current density of Pd-Ni/TiO2 composite coating is smaller and the AC impedance arc radius is larger in 20% sulfuric acid solution at 60 鈩，

本文編號：2480454