發(fā)布時(shí)間：2018-07-08 10:23

  本文選題：無氰電鍍鎘-鈦 + 鈦含量��； 參考：《南昌航空大學(xué)》2017年碩士論文

【摘要】：無氰電鍍鎘-鈦合金鍍層可作為高強(qiáng)度鋼的防護(hù)層,該鍍層中微量的鈦(0.1-0.7%)對(duì)鍍層的氫脆性能和耐蝕性能有較大的影響,但在實(shí)際生產(chǎn)中仍存在鍍層中鈦含量難以控制,鍍液不夠穩(wěn)定易水解等技術(shù)難題,阻礙了該項(xiàng)技術(shù)的推廣應(yīng)用。本文以中性銨鹽鍍鎘液為基礎(chǔ)鍍液,加入自制的氯氧鈦,采用電沉積法制備了鎘-鈦合金鍍層,通過極化曲線法、X射線光電子能譜(XPS)等測(cè)試方法探索了鎘-鈦合金鍍層的電沉積行為;利用掃描電鏡(SEM)、X射線衍射儀(XRD)觀察了鍍層微觀形貌和晶面取向,采用單因素實(shí)驗(yàn)研究了工藝參數(shù)對(duì)鍍層鈦含量的影響;利用“陳化”實(shí)驗(yàn)和“連續(xù)鍍”實(shí)驗(yàn)研究了鍍液的穩(wěn)定性,主要研究結(jié)果如下:1.無氰電鍍鎘-鈦合金鍍液中的鈦酰離子在陰極表面未發(fā)生電化學(xué)反應(yīng),而是在陰極界面處與OH-反應(yīng)生成TiO2和少量的Ti_2O_3,夾雜于鎘鍍層中,其沉積過程推測(cè)為:TiO~(2+)+OH-→ TiO_2+H~+TiO~(2+)+H→ TiO~++H~+2TiO~++2OH-→ Ti_2O_3+H_2O鍍液中鈦鹽的引入增大了工作電流密度區(qū)的陰極極化,使鎘的形核過電位變大,鍍層晶粒變細(xì)。2.自制主鹽氯氧鈦時(shí),鈦與鹽酸的比例控制為1:4(g/ml),中性銨鹽鍍鎘液中引入該自制的氯氧鈦(鈦含量)為4-5 g/L,且鍍液中鈦與鎘的比例為1:3,施鍍時(shí)電流密度控制為2-3 A/dm~2時(shí),獲取10μm鎘-鈦合金鍍層為稻黃色,鈦含量達(dá)0.4%左右,且該鍍液可長(zhǎng)期穩(wěn)定使用。3.無氰鍍純鎘層表面為暗灰色,結(jié)晶粗糙,主要取向?yàn)?101)、(002)面,沉積類型為傾斜型鍍層,而鍍液中引入自制的氯氧鈦所獲取的鎘-鈦合金鍍層(鈦含量約為0.5%)表面呈稻黃色,結(jié)晶細(xì)致,在(101)、(100)、(110)面為主要取向,沉積類型為垂直型鍍層,鈦的引入改變了鍍層的擇優(yōu)取向和沉積類型,有利于氫氣的釋放,降低了氫脆的可能性。另外鎘-鈦合金鍍層的自腐蝕電位為-0.825 V,自腐蝕電流密度為1.765×10-2 A/dm~2,比純鎘鍍層的自腐蝕電位更正,自腐蝕電流密度更小,鍍層的耐蝕性增強(qiáng)。4.“陳化”實(shí)驗(yàn)和“連續(xù)鍍”實(shí)驗(yàn)研究表明:新配制的鍍液pH值為5.99和7.05時(shí),鍍液穩(wěn)定常數(shù)分別為0.886和0.873,18 d后鍍液變渾濁,而pH值為6.7時(shí),穩(wěn)定常數(shù)為0.946,該鎘-鈦合金鍍液在10-60℃室內(nèi)長(zhǎng)期存放時(shí),未產(chǎn)生沉淀,但溫度高于60℃時(shí),鍍液開始渾濁,產(chǎn)生白色沉淀,沉淀產(chǎn)物主要是Ti(OH)_4、TiO_2、H_2Ti_2O_(11)·3H_2O、NH_4Cl;新配制的25 L鍍液連續(xù)施鍍過程中,施鍍至16 d時(shí),通電量為2.07×10~6 C,鍍層鈦含量達(dá)到峰值,至28 d后,通電量為3.63×10~6C,鍍層鈦含量低于0.1%,鍍液中絡(luò)合劑消耗較快,需重新分析補(bǔ)充鍍液的成分,確保其能長(zhǎng)期穩(wěn)定生產(chǎn)。
[Abstract]:The non-cyanide cadmium titanium alloy coating can be used as a protective layer for high strength steel. The trace amount of titanium (0.1-0.7%) in the coating has a great influence on the hydrogen embrittlement and corrosion resistance of the coating, but it is still difficult to control the titanium content in the coating in actual production. The solution is not stable and easy to hydrolyze, which hinders the popularization and application of the technology. In this paper, cadmium-titanium alloy coating was prepared by electrodeposition with neutral ammonium salt cadmium plating solution and adding self-made titanium oxychloride. The electrodeposition behavior of cadmium-titanium alloy coating was investigated by means of X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The effect of technological parameters on titanium content of the coating was studied by single factor experiment, and the stability of plating solution was studied by "aging" experiment and "continuous plating" experiment. The main results were as follows: 1. There was no electrochemical reaction between Ti ~ (2 +) ions and OH- on the cathode surface in the cadmium-titanium alloy plating bath without cyanide. Instead, TIO _ 2 and a small amount of Ti _ 2O _ 3 were formed at the cathode interface to form a small amount of Ti _ 2O _ 3, which was mixed with cadmium coating. The deposition process of TiO2OH- TiO- TiO- TiO- + TiO- TiO- TiO- Ti2O2Ti2O3H- Ti2O3H- Ti2O3H- Ti2O2Ti2O3H- Ti2O2Ti2O3H- Ti2O2Ti2O3H- Ti2O-Ti2O2Ti2O3H- Ti2O-Ti2O-TiO- TiO- TiO- TiO- TiO@@ The ratio of titanium to hydrochloric acid was controlled at 1:4 (g/ml) when the main salt was made by ourselves. The titanium oxychloride (titanium content) was introduced into the neutral ammonium salt cadmium plating solution was 4-5 g / L, and the ratio of titanium to cadmium in the bath was 1: 3, and the current density was 2-3 Ar / dm2 when the plating was applied. The 10 渭 m cadmium-titanium alloy coating is rice-yellow, the titanium content is about 0.4%, and the bath can be used steadily for a long time. The surface of pure cadmium without cyanide plating is dark gray, crystal rough, and the main orientation is (101), (002) surface. The deposit type is inclined type. The surface of cadmium titanium alloy coating (about 0.5% titanium content) obtained by introducing self-made titanium oxychloride into the bath is rice yellow. The crystal is fine, the main orientation is on the (101), (100), (110) surface, and the type of deposition is vertical. The introduction of titanium changes the preferred orientation and deposition type of the coating, which is favorable to the release of hydrogen and reduces the possibility of hydrogen embrittlement. In addition, the self-corrosion potential of the coating is -0.825 V, the self-corrosion current density is 1.765 脳 10 ~ (-2) A / D ~ (-2), the self-corrosion current density is smaller than that of the pure cadmium coating, and the corrosion resistance of the coating is enhanced by .4.The results show that the corrosion resistance of the coating is better than that of the pure cadmium coating. The results of "aging" experiment and "continuous plating" experiment show that when the pH value of the newly prepared bath is 5.99 and 7.05, the bath stability constant is 0.886 and 0.873ng respectively, and the bath becomes turbid after 18 days, while the pH value is 6.7. The stability constant was 0.946. When the cadmium titanium alloy plating bath was stored in room for a long time at 10-60 鈩，

本文編號(hào)：2107124