【作者】 李琳；

【导师】 杨中东；

【作者基本信息】 东北大学 ， 环境科学， 2013， 硕士

【摘要】 钛合金具有密度小、比强度高、耐腐蚀、耐高温等优点,已成为广泛应用于航空、航天、舰艇等国防以及民用机械工业部门的重要结构材料,其中以TC4(Ti-6Al-4V)钛合金用途最为广泛,用量约占钛合金总量的一半以上,但由于钛合金硬度低,耐磨性能较差的局限制约了其在实际生产中的应用。因此,提高钛合金摩擦磨损性能已成为钛合金领域的研究热点。本文主要致力于通过阳极氧化-复合PTFE的方法在TC4钛合金的表面制备具有耐摩擦磨损性能的自润滑膜的研究,首先对影响钛合金阳极氧化膜表面形貌、膜厚的主要因素进行实验研究分析,利用SEM、XRD等测试方法对阳极氧化膜及复合自润滑膜的表面形貌、微观相结构进行分析,并采用摩擦磨损试验机测试其摩擦磨损性能。(1)通过对硫酸体系中钛合金的阳极氧化的研究,分析电解液浓度、NH4HF2添加剂浓度、氧化电压、氧化温度以及氧化时间对氧化膜膜孔、膜厚的影响,讨论影响氧化膜耐磨性能的主要因素。实验结果表明,电解液浓度与氧化电压主要影响氧化膜表面膜孔孔径的大小,随着电解液浓度、电压的升高,孔径增大,在电解液H2SO4浓度为0.3-1mol/L、电压为60-130V范围内,膜孔孔径约为100-500nm之间；阳极氧化温度主要影响氧化膜表面膜孔均匀性,随着温度的降低,氧化膜膜孔均匀性提高；阳极氧化时间对氧化膜厚度有重要影响,在氧化时间为1h-3h范围,氧化膜厚度约为4.4-11.9μm之间；对钛合金阳极氧化膜进行化学腐蚀溶解扩孔处理后,孔径可达200-1500nm之间。对TC4钛合金阳极氧化膜进行摩擦系数测定后发现,具有阳极氧化膜的钛合金表面摩擦系数较钛合金基体显著下降,其降低程度与膜层厚度和膜孔均匀性有关,氧化膜膜层越厚,膜孔越均匀,摩擦系数越低,经测试,阳极氧化前TC4钛合金表面摩擦系数约为0.5,在电解液H2SO4浓度0.8mol/L、温度-5℃、氧化电压130V、阳极氧化时间3h条件下制备的钛合金阳极氧化膜摩擦系数降至0.35；对此条件下的氧化膜进行800℃热处理2h后,氧化膜相结构由锐钛矿和金红石型共存TiO2几乎全部转化为金红石型TiO2,同时摩擦系数也降至0.29。(2)阳极氧化-PTFE自润滑减摩复合膜制备及其摩擦磨损性能研究。实验结果表明,对电解液(H2SO4)浓度0.8mol/L,温度-5℃,氧化电压130V,阳极氧化时间3h条件下制备的钛合金阳极氧化膜进行PTFE涂覆,涂覆液PTFE含量为6.7%,涂覆时间为30mmin,烘干时间1h、温度100℃,测得复合膜层摩擦系数显著降低,约为0.2左右,随着PTFE含量的增加,其摩擦系数持续降低,当PTFE含量为20%时,摩擦系数降至0.13-0.14之间；将上述在PTFE含量为6.7%条件下制得的阳极氧化膜-PTFE自润滑减摩复合膜在200-300℃下进行热处理,则由于PTFE粒子更好的填充膜孔,摩擦系数降至0.12,实验研究表明钛合金阳极氧化-PTFE自润滑减摩复合膜显著提高了钛合金的耐摩擦磨损性能。更多还原

【Abstract】 Titanium alloy has many advantages, such as small density, high strength, corrosion resistance, high temperature resistant. It has become the important structural material which widely used in aviation, aerospace, ships, chemical industry, national defense and civilian industry. The TC4(Ti-6Al-4V) titanium is the most widely used among them, whose dosage accounted for more than half of the total titanium alloy, but the low hardness and poor wear resistance restrict its application in practical production. Surface modification treatment of titanium alloy can improve the friction and wear properties, it has become a hot research in titanium alloy field.This article is focused on using the method of anodic oxidation-PTFE composite coating on the surface of TC4titanium alloy to prepare self-lubricating film which has friction and wear resistance. Meanwhile, analyzed for the main influence factors of surface morphology and film thickness of the titanium anode oxidation film, and using XRD, SEM and other methods to test the surface morphology and microstructure of anodic oxidation film and composite self-lubricating film, and using the friction and wear testing machine to test friction and wear properties.(1) Through the study of anodic oxidation of titanium alloy in sulfuric acid system, analyses the electrolyte concentration, NH4HF2concentration, oxidation voltage, oxidation temperature and oxidation time on surface morphology and thickness of oxide film, discuss the main factors which influence the wear-resisting property of oxidation film. The experimental results show that the change of electrolyte concentration, NH4HF2concentration and the oxidation voltage play a prominent role in surface film hole diameter and film thickness of the oxidation film, the increase of the size of the aperture with the increase of the concentration of electrolyte, voltage, aperture, and under the condition of the electrolyte(H2S04) concentration is0.3-1mol/L, oxidation voltage is60-130V, the diameter of film hole is about100-500nm; oxidation time has a great influence on the thickness of oxide film, the thickness of oxide film is4.4-11.9μm between lh-3h; and the reaction temperature is mainly influence the uniformity of surface membrane pore of the oxidation film. After determining the friction coefficient of TC4titanium alloy anodic oxidation film, it is find that the titanium alloy friction coefficient with anodic oxidation film declined significantly than the not anodized, its reduce level is related with thickness of film and uniformity of membrane pore, the more thicker of the oxidation film, the lower of friction coefficient, the test shows that the friction coefficient TC4titanium alloy is about0.45～0.5before the anodic oxidation, under the condition of the electrolyte(H2SO4) concentration is0.8mol/L, the temperature is-5℃, oxidation voltage is130V, the anodic oxidation time is3h to prepare anode oxidation film,the titanium alloy friction coefficient decline to0.35, thermal treatment this oxide film in800℃for2h under this condition, oxide film phase structure determination (XRD) shows that almost all of their component are rutile type TiO2, friction coefficient decline to0.29.(2) The preparation of anode oxidation-PTFE composite coating and the research foe its friction and wear properties. Experimental results show that under the condition of the electrolyte(H2SO4) concentration is0.8mol/L, the temperature is-5℃, oxidation voltage is130V, the anodic oxidation time is3h to prepare anode oxidation film and coats6.7%PTFE with30min, surface film were blocked by filling, and the friction coefficient significantly reduced to0.2; the friction coefficient continue reduce to0.13-0.14with20%PTFE; thermal treatment under the200-300℃after coating with6.7%PTFE, making the PTFE in the molten state and filling film hole better, the friction coefficient is declined to0.12, the self-lubricating antifriction composite coating significantly improve the wear-resisting property of titanium alloy.更多还原