电化学表面处理对SiC纤维的强化作用

采用SEM分析了用电化学表面处理方法得到的高强度SiC纤维表面形貌和断口的结构,讨论了表面氧化膜的形成对用VCD法制备的SiC纤维力学性能的影响。     

塑料用填料的表面处理与应用效果探讨

本文论述了塑料用的无机填料的表面结构，表面处理方法以及在填充复合体系中的应用效果。     

PP/PMMA接枝剑麻纤维复合材料--(Ⅱ)SF表面处理对PP/SF复合材料结构和性能的影响

分别用碱处理和甲基丙烯酸甲酯接枝聚合的方法对SF进行表面改性．研究了SF表面处理对PP／SF复合材料的热性能、动态力学性能、晶态结构、微观结构和力学性能的影响．结果表明SF表面处理改善了PP与SF间的界面相容性,提高了PP／SF共混物的热稳定性和复合材料的损耗因子强度,增加了β晶型PP的含量,降低了PP相的结晶度。同时提高了PP／SF复合材料的强度和韧性．SF表面接枝PMMA比表面碱处理对PP／SF复合材料结构和性能的影响更为显著．     

浸渍法在聚丙烯基体上负载二氧化钛薄膜

采用TiO2浆料浸渍法在聚丙烯塑料上负载纳米二氧化钛薄膜.研究了不同表面处理方法、表面处理条件和浆料固相含量对TiO2薄膜的形成和结构的影响.用扫描电镜观察了TiO2薄膜的表面形态,用傅立叶变换红外光谱仪和X射线光电子能谱分析了表面处理后聚丙烯表面所带基团、原子及化学态.研究表明,经过离子溅射表面镀Ti膜处理和表面磺化处理后,可改善聚丙烯表面与TiO2粒子间的亲和度,以镀Ti膜的表面形成的TiO2薄膜结构较均匀致密.表面磺化处理存在最佳时间,时间过长,会使表面产生点蚀,影响成膜质量.最佳处理时间与磺化速率有关.浆料中TiO2含量越高,浆料粘度越大,膜越容易开裂和脱落,较低粘度的浆料可获得结构较均匀的膜.     

气相处理对碳纤维表面及其复合材料性能的影响

本文对气相表面处理碳纤维的新工艺进行了系统研究。处理后的碳纤维强度、模量不下降,且其表面能、表面化学官能团含量明显增加;表面微晶结构变小,与环氧树脂复合后,层间剪切强度(LLSS)提高47%左右。本文还对复合材料断口的形态结构进行了分析,说明这种表面处理方法能有效改善碳纤维增强环氧树脂复合材料(CFRP)的界面粘结。     

刻蚀处理对钛表面形貌的影响

发展电化学刻蚀和化学刻蚀技术,对钛表面进行处理,并应用扫描电镜、X射线衍射方法对其表面进行表征,探讨电化学刻蚀钛表面形成微观结构的机理.结果表明,经刻蚀后钛表面形成了纳米级微观结构,提高了表面粗糙度,可增强生物材料涂层与钛基底的结合强度.     

电晕处理对高性能PBO纤维的表面性能及其界面粘接性能的影响

对高性能PBO纤维表面进行了电晕处理,优化了其处理工艺。用XPS,FT-IR和SEM研究了处理前后纤维表面化学结构及物理结构的变化,通过单丝拔出试验和短梁剪切试验评价了PBO纤维与树脂基体的微宏观界面粘接性能。结果表明:经电晕处理后,PBO纤维表面含氧量增多,表面浸润性得到改善,单丝拔出的PBO-环氧界面剪切强度(IFSS)提高了25.6 ％,但短梁剪切强度(ILSS)的提高不明显。     

壳聚糖膜表面的氦等离子体改性研究

采用溶液浇铸法制备了壳聚糖膜,通过氮等离子体对壳聚糖膜进行表面改性以提高其表面亲水性.采缮用扫描电子显微镜(SEM)、表面接触角分析仪和X射线光电子能谱(XPS)对改性前后壳聚糖膜的表面结构和性能进行分析和表征,研究了不同等离子体处理时间和不同放电功率对壳聚糖膜表面结构和性能的影响.结果表明:经氮等离子体处理后,壳聚糖膜的表面接触角可由103.0°降为48.8°,表面亲水性得到明显改善.由XPS分析得知,膜表面的氧、氮含量及氧碳比增加,表面的C-C键发生了断裂而生成新的>C=O(COOR、COOH或CONH)等极性基团,从而使其亲水性增强.     

粉体粒子的表面改质处理评价方法

本文介绍了无机盐或炸药的粉体粒子的表面改质处理的评价方法。各种粉体材料用某些高聚物或表面活性剂处理后,可改变其表面结构和特性,以改善粉体的分散性、在基材中的混炼性、吸湿性以及粉体粒子与粘合剂的粘结强度。本文介绍了实验方去并讨沦了影响测定的主要因素。     

硅烷类偶联剂对蓄光性荧光粉的表面处理

采用硅烷类偶联剂对蓄光性荧光粉YLAG进行了表面处理,并将荧光粉与尼龙66(PA66)进行熔融共混,利用散射式浊度仪、透射电镜、红外光谱、扫描电镜分别研究了表面处理前后荧光粉的沉降性、微观形貌及化学结构的变化,以及荧光粉/聚合物共混体系的形态结构.结果表明,经硅烷偶联剂进行表面处理后,荧光粉与偶联剂有一定键合作用,表面处理后荧光粉的沉降速度明显减小,在PA66中的分散性得以改善.     

NiTi 合金表面激光原位反应合成TiN增强金属基复合材料涂层

采用连续高功率固体Nd-YA G激光辐照, 使预置于NiTi 合金表面的Ti 粉在N₂ 环境中形成TiN 增强Ti 基复合材料涂层。选择适当的激光辐照工艺参数, 获得致密的TiN 增强金属基复合材料激光改性层。SEM 观察及EDAX 成分分析结果表明, TiN/ Ti 金属基复合材料表面改性层与基体NiTi 合金存在良好的冶金结合, 界面处成分均匀过渡, 表面Ni 含量极低。显微硬度测试及磨损实验表明, TiN/ Ti 金属基复合材料改性层显著提高了NiTi 合金的表面硬度和耐磨性, 激光表面改性层可有效地改善NiTi 合金作为生物医学材料使用的表面成分和性能。      

Deposition of Bioactive Layer on NiTi Alloy by Chemical Treatment

A simple chemical method was developed for inducing bioactivity on NiTi alloys(50 at.pct by Ni/Ti).A layer of calcium phosphate was deposited on the surface to improve biocompatibility of thealloy.NiTi alloys were first etched in HNO3 aqueous solution,and then treated with boiling diluted NaOH solution.A rough surface was created and a thin TiO2 layer was formed on the surface.Pre-calcification was then introduced by immersing the treated NiTi alloys in supersaturated Na2HPO4 solution and supersaturated Ca(OH)2 solution in turn before calcification in simulated body fluid (SBF).A dense and uniform bonelike calcium phosphate(Ca-P) bioactive layer was formed on the surfaces of the specimen,which would improve their biocompatibility.Morphology and element analysis on NiTi surfaces during the treatments were investigated in detail by means of environment scanning electron microscopy(ESEM),energy dispersion X-ray spectroscopy(EDXS),and X-ray diffraction (XPD).     

Nitinol surface roughness modulates in vitro cell response: a comparison between fibroblasts and osteoblasts

The purpose of the present in vitro study was to examine the biocompatibility of a nickel–titanium (NiTi) shape memory alloy. Human gingival fibroblastic and rat embryo osteoblastic cells were cultured on NiTi discs. The discs were prepared with two surface roughnesses. Cell response to these surfaces was compared for the two types of cells. The comparison was based on an analysis of the cell morphology, adhesion and proliferation rates. Fibronectin labeling by immunofluorescence staining was also performed. For osteoblastic cells, alkaline phosphatase assay was conducted as a function of NiTi surface roughness and for different durations.     

Erratum to “An analysis of inclusion defects on strip steel surface induced by polyurethane roller [Eng. Failure Anal. 18(3) (2011) 1122–1127]”

In a cold rolling mill, inclusions were inspected on the strip steel surface after multiple cold rolling process in summer season, which caused a large amount of inferior strips. To clarify the reason of the surface defects, experimental research and in situ investigation have been performed. The micro-structure of inclusions was investigated under scanning electron microscope (SEM), and micropits were observed on the strip surface with vermiform particles trapped inside. A large content of carbon was tested in the micro-pit by energy dispersive X-ray analysis (EDAX). Adherents on polyurethane (PU) roller surface and debris in the PU roller bracket were examined by SEM, EDAX and Fourier transform infrared spectroscopy (FTIR) respectively. The vermiform particles were also observed in the SEM analysis of the debris, and the FTIR results of the debris showed good agreement with the PU standard spectrum. It was proved that inclusions were caused by the wear debris from PU roller. Replacing the PU roller in time and enhancing the crystallinity of PU roller were effective methods to eliminate such kind of inclusions.     

Osteoarthritic process modifies expression response to NiTi alloy presence

Nickel-titanium alloy (nitinol, NiTi) is a biomaterial with unique thermal shape memory, superelasticity and high damping properties. Therefore NiTi has been used in medical applications. In this in vitro study, the effect of NiTi alloy (with two surface modifications – helium and hydrogen) on gene expression profile of selected interleukins (IL-1β, IL-6 and IL-8) and matrix metalloproteinases (MMP-1 and MMP-2) in human physiological osteoblasts and human osteoarthritic osteoblasts was examined to respond to a question of the different behavior of bone tissue in the implantation of metallic materials in the presence of cells affected by the osteoarthritic process. The cells were cultivated in contact with NiTi and with or without LPS (bacterial lipolysaccharide). Changes in expression of target genes were calculated by 2^-ΔΔCt method. An increased gene expression of IL-1β in osteoarthritic osteoblasts, with even higher expression in cells collected directly from the metal surface was observed. In case of physiological osteoblasts, the change in expression was detected after LPS treatment in cells surrounding the disc. Higher expression levels of IL-8 were observed in osteoarthritic osteoblasts after NiTi treatment in contact with alloy, and in physiological osteoblasts without relation to location in combination of NiTi and LPS. IL-6 was slightly increased in physiological osteoblastes after application of LPS. MMP-1 expression level was obviously significantly higher in osteoarthritic osteoblasts with differences regarding the metal surface and location. MMP-2 expression was decreased in both cell lines after LPS treatment. In conclusion, results of present study show that the NiTi alloy and the treatment by LPS, especially repeated doses of LPS, change the gene expression of selected ILs and MMPs in human osteoblast cell cultures. Some of the changes were depicted solely to osteoarthritic osteoblasts.     

医用多孔NiTi合金表面微弧氧化改性研究

为解决多孔Ni Ti合金耐蚀性降低和Ni离子释放量增大而引起的使用安全性问题.本文采用微弧氧化技术对医用多孔Ni Ti合金进行表面改性处理,研究结果表明,微弧氧化处理并未改变多孔Ni Ti合金原有的孔隙结构和孔隙率,只在其外表面和孔隙内表面均形成了典型的微弧氧化多孔涂层.该涂层主要由氧化铝相组成,并含有少量的Ti和Ni元素,且外表面涂层的Ti和Ni含量要略低于孔隙内表面涂层.微弧氧化涂层提高了多孔Ni Ti合金的表面接触角,将原有的亲水表面转变成了疏水表面.经微弧处理后,多孔Ni Ti合金的耐蚀性较基体提高了1个数量级以上,Ni离子释放量也较基体降低了1个数量级以上.     

Effect of micro-arc oxidation surface modification on the properties of the NiTi shape memory alloy

In this paper, the effects of micro-arc oxidation (MAO) surface modification (alumina coatings) on the phase transformation behavior, shape memory characteristics, in vitro haemocopatibility and cytocompatibility of the biomedical NiTi alloy were investigated respectively by differential scanning calorimetry, bending test, hemolysis ratio test, dynamic blood clotting test, platelet adhesion test and cytotoxicity testing by human osteoblasts (Hobs). The results showed that there were no obvious changes of the phase transformation temperatures and shape memory characteristics of the NiTi alloy after the MAO surface modification and the coating could withstand the thermal shock and volume change caused by martensite-austenite phase transformation. Compared to the uncoated NiTi alloys, the MAO surface modification could effectively improve the haemocopatibility of the coated NiTi alloys by the reduced hemolysis ratio, the prolonged dynamic clotting time and the decreased number of platelet adhesion; and the rough and porous alumina coatings could obviously promote the adherence, spread and proliferation of the Hobs with the significant increase of proliferation number of Hobs adhered on the surface of the coated NiTi alloys (P?<?0.05).     

Electropolishing of NiTi for Improving Biocompatibility

A modified electrolyte （CH3COOH-HClO4-A-B） for electropolishing （EP） of NiTi was presented for improving the corrosion resistance and biocompatibility of the alloy. Using the proposed parameters, a homogeneous and uniform surface was obtained. Atomic force microscopy （AFM） revealed that the surface roughness （Ra） for EP sample （23.21 nm） was close to mechanical polishing （MP） sample （19.36 nm）. Analysis by X-ray photoelectron spectroscopy （XPS） showed that Ti/Ni ratio increased from 3.1 for MP sample to 27.6 for EP sample. Measurements using potentiodynamic polarization in Hanks＇ solution showed that no pitting occurred for EP sample even though the applied potential increased up to 1500 mV （vs SCE）, while the MP sample was broken down at 650 mV. The present study indicates that electropolishing NiTi with this modified electrolyte contributes to the improved biocompatibility of NiTi.     

On the electropolishing of NiTi braided stents – challenges and solutions

Nickel Titanium (NiTi) alloys possess special mechanical properties and good biocompatibility hence used as base material for the production of vascular stents. Normally, vascular stents are machined from NiTi tubes, using laser cutting processes. Braiding is a promising alternative for the machining of certain NiTi stents. However, a surface finish treatment, such as electropolishing of the braided stents, is still required in order to achieve a medical‐grade surface finish. The thermally‐grown oxide resulting from the shape‐setting heat treatment, following the braiding must be removed. Moreover, electropolishing is required to achieve optimum corrosion resistance. Therefore, the aim of this study is to find suitable parameters for the effective electropolishing of NiTi textile stents. Electropolishing of a device with such a complex geometry is challenging, hence a custom‐designed electrolytic cell was constructed and used in this study. We examined the stent surfaces before and after electropolishing, using scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). Potentiodynamic tests were performed in NaCl 0.9% solution for as‐received and electropolished samples. The results from the present study indicate an improvement in surface quality of the braided stents after electropolishing. Potentiodynamic tests revealed that electropolishing improves the corrosion resistance of the NiTi stents.     

Effect of Ta2O5/TiO2 thin film on mechanical properties,corrosion and cell behavior of the NiTi alloy implanted with tantalum

The NiTi shape memory alloy has been modified by plasma immersion ion implantation (PIII) with Ta at different incident currents to improve the corrosion resistance and other surface and biological properties. The surface topography, chemical components, mechanical properties, corrosion resistance and cytocompatibility are investigated. Atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) revealed that Ta implantation led to the formation of compact Ta₂O₅/TiO₂ nano-film on the surface of the NiTi alloy. The results of Auger electron spectroscopy (AES) showed that Ni was suppressed in the superficial surface layer of the modified NiTi alloy samples. The results of nano-indentation illustrated a lower level of nano-hardness and Young's modulus after Ta implantation. Potentiodynamic anodic polarization curves showed that the corrosion resistance of NiTi alloys was enhanced by Ta implantation. Cells reached confluency and a double-layered structure had developed after cultured for three days. The NiTi alloy modified by a moderate incident current possesses a uniform and slippery surface morphology and the largest surface roughness, leading to the best corrosion resistance and the highest cell proliferation rate, respectively.