TC4钛合金阳极氧化着色膜显色规律探讨

目的在不同电解液、电压等工艺参数下对TC4钛合金进行阳极氧化,获得彩色膜,分析探讨着色膜颜色随不同工艺参数变化的显色规律,并通过该显色规律分析着色膜显色机理。方法分别选用NaOH电解液、H3PO3电解液、Na2SiO3盐溶液对Ti6A14V钛合金进行氧化着色。通过金相显微镜、SEM、XRD、AFM和3nh色差仪等测试方法,分析氧化膜层显微组织、形貌特征、物相成分、膜层厚度与颜色变化。结果3nh色差仪测得膜层颜色值(L^*、a^*、b^*)随电压具有周期变化规律。在电压参数为120 V左右的起弧电压之前,三种电解液阳极氧化着色膜均是由非晶态的钛氧化物组成,显色规律一致,氧化膜层致密均匀,只是生长速率稍有不同。膜层显色是干涉加强光色与干涉减弱光色的互补光色的共同作用。通过钛合金氧化膜干涉光程差公式修正,推导出了薄膜厚度的理论计算公式,且AFM测试结果与理论计算得出的膜厚基本一致。随着电压继续升高,电解反应剧烈,宏观表面观察到微弧放电现象,电解过程过渡到微弧氧化阶段。结论在低电压阳极氧化阶段,TC4钛合金着色膜层是由致密均匀的非晶态钛氧化物组成,膜层生长方式是随电压均匀层状生长,显色原理主要是薄膜干涉原理。通过控制电压参数,可控制膜层厚度,继而得到理想的颜色。在Na2SiO3盐溶液中的膜层生长速率为1~1.7 nm/V。

Study on the Color Development of Anodic Oxidation Film of TC4 Titanium Alloy

The work aims to anodize TC4 titanium alloy under different electrolytes and different voltages to obtain color film, discuss the coloration of color film with different process parameters, and analyze the coloration of color film by the color development rule. Ti6A14V titanium alloy was oxidized and colored by NaOH electrolyte, H3PO3 electrolyte and Na2SiO3 salt solution. The microstructure, morphology, phase composition, film thickness and color change of the oxide film layer were analyzed by metallographic microscope, SEM, XRD, AFM and 3nh color difference meter. The color of the film (L*, a*, b*) measured by the 3nh color difference meter had a periodic variation with the voltage. Before the voltage parameter was about 120 V, the anodic oxidation film of the three electrolytes was composed of amorphous titanium oxide, with the same color development law. The oxide film layer was dense and uniform, but the growth rate was slightly different. Film color development was a combination of interference enhancing light color and interference complementary light color. Through the formula of interference optical path difference of titanium alloy oxide film, the theoretical calculation formula of film thickness was derived. The AFM test results were basically consistent with the theoretically calculated film thickness. As the voltage continued to rise, the electrolysis reaction was severe, the micro-arc discharge phenomenon was observed on the macroscopic surface, and the electrolysis process transitioned to the micro-arc oxidation stage. In the low-voltage anodization stage, the TC4 titanium alloy colored film layer is composed of dense and uniform amorphous titanium oxide. The growth mode of the film layer is uniform layer-like growth with voltage. The principle of color development is mainly the principle of thin film interference. The voltage parameters can control the film thickness to obtain the desired color. The film growth rate in the Na2SiO3 salt solution is from 1 nm/V to 1.7 nm/V.