Na2B4O7对钛合金微弧氧化涂层耐磨和耐腐蚀性能的影响  

Effect of Na2B4O7 on Wear and Corrosion Resistance of Micro-arc Oxidation Coating on Titanium Alloy

作　　者：师文海 海几哲[1] 单春龙 张相哲 杨清炜 马学海[3] SHI Wenhai;HAI Jizhe;SHAN Chunlong;ZHANG Xiangzhe;YANG Qingwei;MA Xuehai(College of Mechanical Engineering,Xinjiang University,Urumqi 830000,China;Sixth Affiliated Hospital of Xinjiang Medical University,Urumqi 830000,China;Key Laboratory of Mental Development and Learning Science,Xinjiang Normal University,Urumqi 830000,China)

机构地区：[1]新疆大学机械工程学院,乌鲁木齐830000 [2]新疆医科大学第六附属医院,乌鲁木齐830000 [3]新疆师范大学心智发展与学习科学重点实验室,乌鲁木齐830000

出　　处：《表面技术》2024年第24期88-98,共11页Surface Technology

基　　金：国家自然科学基金地区科学基金(52165026);机械制造系统工程国家重点实验室开放课题(sklms2021011)。

摘　　要：目的提高钛合金微弧氧化(Microarc Oxidation,MAO)涂层的耐磨和耐腐蚀性能,探究更优复合电解液。方法在磷酸盐和硅酸盐电解液中,通过分别加入不同含量的四硼酸钠,调控氧化过程中的化学反应和微弧放电类型,从而降低涂层表面的粗糙度,改变涂层的内部结构、厚度及二氧化钛的相变,最终提高涂层的耐磨性能和耐腐蚀性能。结果在硅酸盐电解液中,四硼酸钠的加入使得涂层表面粗糙度Sa从5.408μm降到1.089μm,涂层表面突起颗粒物消失并形成孔状结构,相比TC4钛合金自腐蚀电流密度降低了2~3个数量级,磨损量也大大降低。在磷酸盐电解液中添加四硼酸钠也表现出相同的趋势。结论四硼酸钠不仅可以通过溶解涂层表面氧化物,降低涂层表面粗糙度;还可以通过形成新的微弧放电类型,增加涂层的厚度并改变其内部结构。其中在两种基电解液中加入5 g/L的四硼酸钠得到的涂层在各自组中均显示出最优性能,同时发现,在模拟体液中进行摩擦实验时,MAO涂层可诱导羟基磷灰石润滑层形成保护基底。四硼酸钠的加入提高了涂层的亲水性,在摩擦实验中诱导形成更多的羟基磷灰石。其中,磷酸盐基电解液形成的涂层亲水性更好,在摩擦过程中诱导形成的磷灰石含量是硅酸盐涂层的数倍。Micro-arc oxidation(MAO)technology is often used in the surface treatment of medical titanium alloys,giving them abrasion-resistant,corrosion-resistant,or osteogenic properties.The performance of the MAO coating is determined by a combination of factors,such as power supply mode,voltage/current size,electrolyte type,oxidation time,additives,etc.The composition of the electrolyte is one of the key factors affecting the structure and performance of the MAO coating.Sodium tetraborate is used as a single electrolyte for micro-arc oxidation,and due to its special discharge method,the coating often results in high corrosion resistance.However,when sodium tetraborate is used as an additive,it not only plays a discharge role,but also may react with the coating,and the effect of adding sodium tetraborate to different electrolytes is worth exploring.The work aims to improve the wear resistance and corrosion resistance of micro-arc oxidation coatings on titanium alloy and develop better composite electrolytes.In phosphate and silicate electrolytes,by adding varying amounts of tetraborate sodium,the chemical reactions and micro-arc discharge methods during the oxidation process were altered to reduce coating surface roughness,modify internal structure,thickness,and titanium dioxide phase transformation,ultimately improving the wear and corrosion resistance of the coating.Titanium alloy were made into 30 mm×20 mm×5 mm samples,and sandpaper was used to grind to 1200 mesh.In the MAO process,the unipolar pulse was used,the anode current density was set to 2.6 A,the frequency was set to 900 Hz,and the duty cycle was 15%.The silicate electrolyte contained 15.0 g/L Na2SiO3·9H_(2)O and 2.0 g/L NaOH,and the phosphate electrolyte contained 15.0 g/L Na3PO4·12H_(2)O and 2.0 g/L NaOH.Different amounts of sodium tetraborate were added to the electrolytes in the two groups,and the duration of the MAO process was 12 min.The surface and side morphology of the MAO coating were analyzed by scanning electron microscope,and the elemental com

关 键 词：钛合金 添加剂 微弧氧化 电解液 四硼酸钠 耐磨性能 

分 类 号：TG174.4[金属学及工艺—金属表面处理]