Corrosion resistance and hemocompatibility of multilayered Ti/TiN-coated surgical AISI 316L stainless steel

Ti/TiN-multilayered films were prepared on surgical AISI316L stainless steel by arc ion plating. The crystallographic orientation and surface morphology were studied using XRD and SEM. The corrosion resistance of the coated specimen was evaluated by open-circuit test and potentiodynamic polarization test. It was found that the multilayered Ti/TiN-coated specimen had a weaker tendency towards corrosion and higher corrosion resistance in simulated bodily fluid than the bare substrate and the TiN-coated specimen. Additionally, in vitro hemocompatibility of the multilayered film and AISI316L was evaluated by dynamic clotting time and platelet adhesion experiments. The results indicated that for the multilayered Ti/TiN-coated specimen, the clotting time was lengthened and the adhesion and mutual interaction of platelets on its surface was also restrained.     

Evaluation of TiO2 coatings obtained using the sol–gel technique on surgical grade type 316L stainless steel in simulated body fluid

Gel titania is the titania which was prepared by hydrolysis of a titanium isopropoxide through a sol–gel process. A film of this titania was coated on surgical grade 316L stainless steel using a sol–gel dipping technique. The densified films at 700 °C in vacuum were characterized by X-ray diffraction and EDXA analysis for its crystallinity and purity. The content of the films were determined by FT–IR spectroscopy. The morphology of the coating was analyzed by SEM. The corrosion behavior of 316L SS samples coated with densified titania films were studied in simulated body fluid Ringer's solution by DC potentiodynamic polarization and AC impedance spectroscopic methods. The corrosion kinetic parameters show a considerable increase in the corrosion resistance for the coated steel samples in comparison to the pristine steel substrates.     

基体偏压模式对CrN薄膜结构和阻氢性能的影响

为了避免金属材料因为氢扩散而导致的失效,通常在其表面制备氧化物或氮化物等的阻氢薄膜,而薄膜的微观组织、晶体结构等对其阻氢性能的影响显著.本文在不锈钢基体上制备出CrN阻氢薄膜,系统研究了高/低基体偏压调制模式对CrN薄膜结构和阻氢等性能的影响.采用高功率磁控溅射技术在四组基体偏压模式下分别制备了具备一定高温抗氧化性的C...     

Si3N4和52100钢对磨副材料对CrN薄膜干摩擦学行为的影响

利用阴极电弧离子镀技术在316L不锈钢基体上制备了CrN薄膜。采用扫描电子显微镜(SEM)、X射线衍射仪(XRD)、纳米压痕仪对CrN薄膜的形貌、成分和力学性能进行了表征。为了研究Si_3N_4和52100钢对磨副材料对CrN薄膜和316L不锈钢干摩擦行为的影响,在2N、5N、8N三种载荷下,将CrN薄膜和316L不锈钢基体与Si_3N_4陶瓷球和52100钢球分别进行了往复式滑动干摩擦实验。采用扫描电子显微镜观察了磨痕的微观形貌,并对CrN薄膜和316L不锈钢基体的磨损机制进行了分析。结果表明:CrN薄膜表面平整,缺陷较少;CrN薄膜的纳米硬度约为28GPa,弹性模量约为350GPa;与Si_3N_4陶瓷球相比,CrN薄膜与52100钢球摩擦时摩擦因数相对较小(保持在0.7左右)且更加稳定;316L不锈钢的摩擦因数远大于CrN薄膜且波动较大;对磨球为Si_3N_4陶瓷球时,CrN薄膜的主要磨损机制为磨粒磨损,伴有少量的氧化和黏着磨损,316L不锈钢的磨损机制主要为磨粒磨损和塑性变形,伴有少量的氧化和黏着磨损;对磨球为52100钢球时,CrN薄膜的主要磨损机制为黏着磨损,伴有少量的氧化,316L不锈钢的磨损机制主要为黏着磨损,伴有少量的氧化和磨粒磨损。CrN薄膜与两种对磨球的磨损量均小于316L不锈钢基体的磨损量,说明CrN薄膜有效提高了基体的耐磨性。     

Ti/TiN纳米多层薄膜改性层在Troyde s模拟体液中的抗腐蚀性能

用电弧离子镀设备，在医用不锈钢基体上沉积Ti／TiN纳米多层薄膜，考察薄膜在Troyde’s模拟体液中的抗腐蚀性能．结果表明，在中性与酸性模拟体液中316L Ti／TiN(45／45s)体系的击穿电位分别提高5倍和2倍，腐蚀电流密度为基体的1／8与1／3，明显降低发生局部腐蚀的敏感性，但滞后环的出现说明薄膜被击穿后自修复能力较差．分析说明薄膜的纳米多层结构与纯Ti层的存在可有效提高医用不锈钢在Troyde’s模拟体液中的抗点蚀能力．     

Advances in DLC coatings by hybrid PSII and PECVD as a barrier to corrosion in simulated body fluid*

In this study, diamond-like carbon (DLC) films were deposited on biomedical AISI316L stainless steel by hybrid plasma source ion implantation (PSII) and plasma-enhanced chemical vapour deposition (PECVD). Potentiodynamic polarization tests and Electrochemical Impedance Spectroscopy (EIS) have been employed to investigate the corrosion performance of different DLC films in Tyrode's simulated body fluid (pH = 7.4). The corrosion resistance of the DLC films by PECVD deteriorated rapidly after 24 h of immersion, but those made by hybrid PSII and PECVD offered more effective barrier for AISI316L stainless steel during 72 h of immersion. The test results demonstrated that the DLC film by hybrid PSII and PECVD possessed less corrosion current density, greater corrosion resistance, and more positive breakdown potential in simulated body fluid.     

掺钽TiO2薄膜的生物活性研究

采用射频磁控溅射技术在表面纳米化316L不锈钢基体上制备掺钽TiO2薄膜,研究了不同掺钽量对表面纳米化316L不锈钢基TiO2薄膜形貌、结构、亲水性和生物活性的影响规律。结果表明掺杂适量的钽能够细化TiO2薄膜颗粒;掺钽能够改善TiO2薄膜的亲水性和生物活性;含钽36%的TiO2薄膜表面自由能比未掺杂时提高了30.1mN/m,在SBF溶液中能促进羟基磷灰石在其表面晶化。     

Corrosion behavior and passive film chemistry of 216L stainless steel in sulphuric acid

Corrosion behavior and chemical structure of the passive film of a newly developed 200 series austenitic stainless steel (216L) were studied in sulfuric acid (H₂SO₄) and compared with 316L. From potentiodynamic polarization studies it was found that the corrosion behavior of 216L closely follows that of 316L. The breakdown of passivity was evaluated by addition of sodium chloride (NaCl). The immersion tests revealed that the corrosion rate of 216L in various concentrations of H₂SO₄ at ambient temperature is equivalent to 316L. X-ray photoelectron spectroscopy (XPS) analysis of the passive film formed on 216L revealed enrichment of Cr ions on the surface while Mo and N compounds were also present. Ni and Mn ions were conspicuous by their absence in the passive film.     

纳米结构316L不锈钢基掺钽TiO_2薄膜生物活性研究

采用射频磁控溅射技术在表面微结构纳米化316L不锈钢和粗晶粒316L不锈钢基体上制备掺钽TiO2薄膜。采用扫描电镜和X射线衍射仪分析薄膜形貌和晶体结构,用体外模拟人体体液浸泡实验研究薄膜的生物活性。结果表明:表面微结构纳米化的316L不锈钢具有强烈诱导掺钽TiO2薄膜形核效应;316L不锈钢表面微结构纳米化能显著提高自身及其表层掺钽TiO2薄膜的生物活性;316L不锈钢表面纳米化后,其表层掺钽TiO2薄膜诱导的羟基磷灰石形貌由原先的球状变为多孔网状结构。     

The preparation and blood compatibility of pure iron thin film using filter cathode vacuum arc

用磁过滤阴极真空弧源法在单晶硅基片上制备纯铁薄膜,分析了薄膜表面的组成、元素价态和薄膜的物相结构,研究了薄膜的腐蚀降解行为和抗凝血性能. 结果表明:具有纳米晶粒的纯铁薄膜其腐蚀速率低于普通晶粒的纯铁,在纯铁薄膜表面粘附的血小板数量少于316L不锈钢, 且激活和团聚比较轻微,增生的伪足数量比较少;纯铁薄膜表面对血浆中的凝血因子激活比较轻微,具有较好的抗腐蚀性和血液相容性.     

Ti和TiO2薄膜在血管支架表面附着状况的研究

采用非平衡磁控溅射法在316L不锈钢制成的血管支架表面制备Ti以及TiO2薄膜,初步研究了Ti薄膜厚度、TiO2薄膜沉积速率对薄膜在血管支架表面附着状况的影响.结果表明,支架表面较薄的Ti薄膜附着状况较厚的Ti薄膜好;低沉积速率制备的TiO2薄膜在支架表面附着状况好于高沉积速率制备的TiO2薄膜;对于Ti/TiO2复合薄膜,Ti层厚度过大不利于Ti/TiO2复合薄膜在支架表面附着.     

Chemical composition and corrosion resistance of passive chromate films formed on stainless steels 316 L and 1.4301

The chemical composition and corrosion behavior of the natural and formed by chemical treatment in chromium-containing solution passive films on 316 L and 1.4301 stainless steel surfaces have been investigated by means of X-ray photoelectron spectroscopy and electrochemical in situ method of anodic polarization curves. It have been established that the oxide films formed by the chemical treatment have different chemical composition (Cr-enriched), color and reduced corrosion resistance compared to the natural passive films on both steels. The results have shown that the lower part of the oxide layer represents a uniform modified passive film and the upper one is a porous Cr³⁺-enriched film with an island-like structure. The latter permits a direct contact of the solution with the modified passive film which controls the corrosion resistance by the dissolution of the Fe³⁺ oxides present in the lower thinner layer.     

高氮奥氏体不锈钢耐点蚀性能研究

目前产于高氮不锈钢的研究多集中于理论基础、制造工艺和力学性能等方面,有关耐蚀性方面的研究有限。通过循环极化、Mott-Schottky曲线以及电化学阻抗(EIS)等方法,研究了Cr23Mo1N奥氏体不锈钢(高氮钢,HNSS)和316L不锈钢在Cl-溶液中的耐点蚀性能。结果表明:与316L不锈钢相比,高氮钢具有更正的自腐蚀电位,更小的维钝电流密度。阻抗谱表明高氮钢的钝化膜比316L更加稳定,且电荷转移电阻更大。Mott-Schottky曲线表明高氮钢的点缺陷施主浓度比316L不锈钢低一个数量级,钝化膜的绝缘性更好。循环极化曲线表明高氮钢的点蚀敏感性更小,钝化膜的自修复能力更强,耐蚀性能更加优越。     

Synthesis of nanostructured zirconia electrodeposited films on AISI 316L stainless steel and its behaviour in corrosion resistance assessment

This work deals with the study of AISI 316L stainless steel samples coated with nanostructured zirconia thin films, using electrodeposition methods. The chemical composition and compounds formed were determined by X-ray photoelectron spectroscopy (XPS). The morphology of zirconia films was analysed by scanning electron microscopy (SEM) and atomic force microscopy (AFM).Corrosion resistance of the coated steel was tested in a chloride environment. XPS analysis results show zirconium element on the metal surface, bound to oxygen-forming zirconia. The anodic polarization curves obtained in Hank's solution show that zirconia coating can be used as protective coating against pitting corrosion of AISI 316L stainless steels.     

AZ31镁合金表面磁控溅射Zr(Al,Ti)-SiN_x复合薄膜及其耐蚀性能

镁合金表面沉积薄膜可以提高其耐蚀性,但现有的几种沉积方法得到的膜疏松、与基体结合力差,影响了其耐腐蚀性能.为此,采用磁控溅射法在AZ31镁合金表面制备了Al,Zr,Ti膜及其与SiN_x的复合薄膜.用扫描电镜、X射线衍射、XPS研究了金属膜及其与SiNi_x复合薄膜的晶体结构、表面形貌和化学成分.结果表明:所制备的SiN_x薄膜为非晶态的富N膜;Zr膜的耐腐蚀性最好,Al膜的保护性最差;Zr-SiN_x复合薄膜比AZ31镁合金的腐蚀电流密度降低了3个数量级,Ti-SiN_x复合薄膜在阳极极化区出现了钝化.SiN_x复合薄膜的耐腐蚀性优于AZ31镁合金和单一金属膜.     

铁氧化菌作用下316L不锈钢点蚀电化学特性的研究

采用电化学测量、交流阻抗技术、扫描电镜观察和能谱分析等实验方法,研究了316L不锈钢在铁氧化菌(IOB)溶液中的腐蚀电化学行为,分析了炼油厂冷却水系统微生物腐蚀的特征及机制,结果表明,在含有IOB溶液中的自腐蚀电位(Ecorr)、点蚀电位(Epit)和极化电阻(Rp)均随浸泡时间的增加呈现出降-升-降的变化趋势;在含有IOB溶液中的腐蚀速率均大于在无菌溶液中;IOB的生长代谢活动及其生物膜的完整性和致密性影响了316L不锈钢表面的腐蚀过程,使不锈钢表面的钝化膜层腐蚀破坏程度增加,加速了316L不锈钢的点蚀.     

Microstructure-mechanical and chemical behavior relationships in passive thin films

The passive films play an important role in corrosion and stress corrosion cracking of austenitic stainless steels. The current research investigates the relationship between alloy chemistry, microstructure, and mechanical behavior of passive films formed on 316, 304, and 904L stainless steels (SS). X-ray photoelectron spectroscopy and transmission electron microscopy were used to investigate the effect of alloy chemistry and microstructure constituents on the thin film fracture properties determined by nanoindentation tests. The analyses showed that fracture loads are directly related to the crystallography of the thin films. It was found that decreasing the ratio of iron to other metallic elements in the film led to an increase in the load required to fracture the film. It was also found that films grown on 304, 316, and 904L stainless steels were the cubic polymorph of Cr₂O₃, rather than the lower energy rhombohedral form. In the case of 904L SS the film formed as an epitaxial layer. In the other two cases it consisted of small crystalline islands in an amorphous matrix. A dichromate treatment of 316 SS decreased the iron content in the oxide film and increased the hardness. It also resulted in an epitaxial film.     

Elaboration of sol–gel derived apatite films on surgical grade stainless steel for biomedical applications

Thin film hydroxyapatite deposits through dip-coating onto prefinished low carbon 316L stainless steel substrates were prepared using alkoxide based sol–gel technique. This technique provides several advantages in the control of microstructure and the thickness of the coatings. The coatings were annealed in vacuum; sintering temperature reaching 900 °C were applied to enhance the crystallinity and purity of the films. The resultant coatings have been characterized by the use of FT-IR, XRD, EDXA SEM ICP-AES, shear bond strength and potentiodynamic polarization. The experimental results revealed that the crystallinity, microstructure, corrosion resistance and morphology of the coatings prove the formation of hydroxyapatite coating appropriate for several biomedical applications.     

Influence of steel composition and pre-treatment conditions on morphology and microstructure of TiO2 mesoporous layers produced by dip coating on steel substrates

Mesoporous titania films were prepared by template-assisted dip coating on AISI 430, 304 and 316Ti steel substrates that underwent different pre-treatment, namely grinding, grinding–calcination and grinding–etching. The influence of steel grade and pre-treatment conditions on the film morphology and microstructure was studied, and reasons for film degradation were elucidated. Among tested steels, 430 interfered with the coating process the most yielding films of poor integrity and with a strongly distorted pore structure. Steels 304 and 316Ti showed better resistance to the precursor solution, resulting in less fractured films and defined pore morphology. Grinding and subsequent calcination proved to be the best choice among tested pre-treatment methods which reflected in improved film quality. The results show that only a proper combination of steel grade and substrate pre-treatment affords high-quality titania coatings with defined porosity.     

Gradient CrCN cathodic arc PVD coatings

This work reports on the growth and properties of Cathodic Arc Physical Vapor Deposition of low friction-coefficient CrCN coatings, as deposited on the basis of complementary carbon/nitrogen gradient concentrations through the film thickness. The coatings developed in this study exhibited friction coefficients ranging from 0.2 to 0.6, against 100Cr6 bearing steel, depending on the preparation conditions. Gradient CrCN films with COF of 0.35 and comparable mechanical strength to that of CrN were achieved. The adhesion rate of metallic elements such as Fe during the sliding process of CrCN coated tools on AISI316L steels were monitored using a pin-on-disc experimental set-up. The results demonstrated a low tendency of the gradient CrCN deposited films to pick up material from the AISI316L steels surfaces, in contrast to that found when using standard CrN cathodic arc PVD films.