Graded glass coatings for Co-Cr implant alloys

A graded glass coating for Vitallium®, a Co-Cr alloy, has been prepared using a simple enameling technique. The composition of the glasses has been tailored to match the thermal expansion of the alloys. The optimum glass composition and firing conditions (temperature and time) needed to fabricate homogeneous coatings with good adhesion to the alloy were determined. The final coating thickness ranged between 25 and 60 μm. Coatings fired under optimum conditions do not delaminate during indentation tests of adhesion. Excellent adhesion to the alloy has been achieved through the formation of 100 nm thick interfacial chromium-oxide (CrOx) layers. The graded glass (consisting of BIG and 6P50 layers) can be successfully coated to a Co-Cr alloy, and forms hydroxyapatite (HA) on the coating surface when immersed in a simulated body fluid (SBF) for 30 days.     

Hydroxyapatite coating by biomimetic method on titanium alloy using concentrated SBF

This article reports a biomimetic approach for coating hydroxyapatite on titanium alloy at ambient temperature. In the present study, coating was obtained by soaking the substrate in a 5 times concentrated simulated body fluid (5XSBF) solution for different periods of time with and without the use of CaO-SiO₂ based glass as a possible source of nucleating agent of apatite formation. Optical microscopic and SEM observations revealed the deposition of Ca-P layer on the titanium alloy by both the methods. Thickness of coating was found to increase with the increase in immersion time. The use of glass did not help the formation of apatite nuclei on the substrate and the coating obtained by this method was also not uniform. EDX analysis indicated that the coating consisted of Ca-P based apatite globules, mostly in agglomerated form, and its crystallinity was poor as revealed by XRD.     

玻璃-陶瓷保护涂层对钛合金表面润湿性的研究

为了减少钛合金在热处理过程中高温氧化所造成的损失，采用耐高温玻璃－陶瓷涂层进行保护，并对涂层的制备进行了介绍。涂层的保护性能 与其在高温下对钛合金表面的润湿性能有密切关系，当涂层加入一些特定氧化物（B2O3，TiO2)时，涂层在热处理过程中对钛合金有很好的润湿作用，能保护其不被氧化。     

一种提高FeCrNi合金材料抗结焦能力的玻璃涂层

由于加工石油的裂解FeCrNi合金制造,其抗结焦性能差,因而采用玻璃涂层来提高FeCrNi合金材料的抗结焦能力。以HP炉管材料作为FeCrNi合金基体,制备玻璃涂层,并对玻璃涂层与基体的结合性能和涂层试样的抗结焦能力进行了实验研究。结果表明,玻璃涂层与基体结合牢固、均匀致密、具有良好的抗结焦能力,本法制备的涂层能提高FeCrNi合金材料的抗结焦能力。     

玻璃基体上电沉积Ni-Co合金镀层的性能研究

对玻璃基体上电沉积Ni Co合金镀层的工艺及镀层的性能进行了研究 ,对底镀层的形貌、成分、结构进行了观察和分析 ,并测定了镀层的耐腐蚀性。结果表明 ,镀层在 0 .5mol/LH2 SO4 和 5%NaCl(pH =3 )中的耐蚀性与 1Cr18Ni9Ti相当     

镍、铁基喷焊层组织与性能研究

为寻找具有耐盐酸腐蚀能力的喷焊用合金粉末,自行设计了3种喷焊粉末,并对比研究了自制粉末与商业Ni60粉氧乙炔喷焊层的显微硬度、显微组织形貌和耐盐酸腐蚀性能.结果表明,自制1号粉喷焊层的显微硬度值明显高于商业Ni60喷焊层,自制2号粉喷焊层的显微硬度和耐蚀性均优于商业Ni60喷焊层.分析认为,钼的加入可改善合金粉末的喷焊工艺性,提高喷焊层的耐盐酸腐蚀性能;铬含量的增加显著提高了喷焊层的显微硬度;喷焊层中铁含量的增加对耐盐酸腐蚀性能有不利影响.     

Bioactive glass and glass-ceramic-coated hip endoprosthesis: experimental study in rabbit

Co–Cr–Mo endoprostheses with a dual bioactive glass (BG) coating and titanium implants coated with a bioactive glass-ceramic (BGC) were studied under lead-bearing conditions in the rabbit hip. The dual BG coating contained an inner layer of high durability and an outer bioactive layer. Each type of coating improved the stabilization of prosthesis during the experiment period of 8 weeks compared to non-coated control implants. EDXA analysis confirmed the ability of BG and BGC coatings to bond chemically to bone. The BGC coating on titanium alloy proved superior to the dual BG coating on Co–Cr–Mo prosthesis with regard to bone formation on the surface of the implant. The bioactive top layer of the dual BG coating showed resorption, especially in the areas without direct bone contact. This is explained by partial crystallization of the glass during firing. Thermal discrepancy between BGC coating and titanium core caused cracking of the coating, which remains a major obstacle to its use as a bioactive coating.     

铜合金表面新型金属陶瓷涂层材料的性能

航天发动机某热端零部件采用的QCr0.8材料,由于经受高温、高速富氧燃气的冲刷,通常会发生高温氧化或者冲刷烧蚀而失效,其应用条件严苛。经分析与研究,选择在Ni-Pb_3O_4-B_2O-BaO-SiO_2体系玻璃相中加入适当的磨料,成功地制备了铜合金表面新型金属陶瓷涂层。采用热震试验及氧化试验对比了磨料中不同比例的镍粉添加量对涂层性能的影响;根据宏观形貌观察并结合SEM微观形貌分析了涂层的形貌以及界面特点。结果表明:镍粉与玻璃熔块添加比为1.2∶1.0的涂料抗热震、抗氧化性能最好,可以有效保护基体。     

The use of XPS for characterisation of glass fibre coatings

We present the results of an investigation of the use of X-ray photoelectron spectroscopy (XPS) as a tool for the rapid characterisation of glass fibre coatings. XPS data have been obtained from a wide range of commercial and experimental glass fibres using three different XPS instruments. By developing a protocol to plot ratios of appropriate atom concentrations, XPS analysis has been shown to give new insights into the in situ nature of the coating on glass. We show how these plots of atom ratios can be used to estimate the surface coverage of the coating on the glass fibres and obtain information on the chemical composition of the coating. Relationships between the XPS data and coated glass fibre parameters are clarified with the aid of a patchy overlayer model. We discuss the use of the XPS Si peak as a glass reference atom in different coverage regimes, and the effect of different XPS detector exit angles. In comparing data from three XPS instruments excellent correlation was obtained after correcting for differences in spectrometer sensitivity factors.     

低熔点玻璃粉包覆FeSiAl合金的结构和电磁性能

将低熔点玻璃粉D250绝缘包覆剂与扁平化的FeSiAl合金粉末机械混合,进行热处理使D250熔融流动而包覆在片状FeSiAl粉末表面。借助XRD,SEM,XRF和EDS等手段研究了包覆后粉末的物相组成、表面形貌和元素组成;用矢量网络分析仪测试了材料在1~18 GHz频率范围内的电磁参数和反射损耗。结果表明,熔融包覆后的粉末形成均匀致密的包覆层,其复介电常数的实部降低到8左右。热处理温度为700℃时材料的最大反射损耗降至-40.10dB,有效频宽达到3.76 GHz。     

Effect of mechanical coating with Ni and Ni–5% Al on the structure and electrochemical properties of the Mg–50% Ni alloy

The Mg–Ni metastable alloys (with amorphous or nanocrystalline structures) are promising candidates for anode application in nickel–metal hydride rechargeable batteries due to its large hydrogen absorbing capacity, low weight, availability, and relative low price. In spite of these interesting features, improvement on the cycle life performance must be achieved to allow its application in commercial products. In the present paper, the effect of mechanical coating of a Mg–50 at.% Ni alloy with Ni and Ni–5 at.% Al on the structure, powder morphology, and electrochemical properties is investigated. The coating additives, Mg–Ni alloy and resulting nanocomposites (i.e., Mg–Ni alloy + additive) were investigated by means of X-ray diffraction and scanning electron microscopy. The Mg–Ni alloy and nanocomposites were submitted to galvanostatic cycles of charge and discharge to evaluate their electrode performances. The mechanical coating with Ni and Ni–5% Al increased the maximum discharge capacity of the Mg–Ni alloy from of 221 to 257 and 273 mA h g⁻¹, respectively. Improvement on the cycle life performance was also achieved by mechanical coating.     

玻璃润滑涂料对钛合金模锻的抗氧化防护作用

以硼硅酸盐玻璃粉为主体,加入有机粘结剂,以水为溶剂,研制了一种无毒、无污染的钛合金高温模锻防护润滑涂料.探讨了涂层在不同温度、时间下氧化增重、显微硬度、表面形貌及表面元素的变化情况,并分析了硼硅酸盐玻璃组分的作用及抗氧化机理.结果表明,该涂料在600～900℃钛合金锻造温度范围内具有良好的抗氧化性能.     

消失模铸造镁合金表面陶瓷化研究

利用消失模铸造工艺,以PbO-ZnO系低温玻璃粉作为主要的陶瓷化材料,进行了镁合金表面陶瓷化研究。利用SEM、XRD、线能谱分析和极化曲线等手段研究了镁合金表面陶瓷涂层的组织结构、相组成和元素的分布,测试了陶瓷层的耐腐蚀性能。结果表明,在基体的表面形成厚度为40～80μm左右的陶瓷涂层,涂层的主要成分有低温玻璃粉组成,并且成分组成由表层到基体变化明显,与基体之间形成了良好的结合界面。通过电化学性能测试表明,表面陶瓷层的腐蚀电位大幅度的提高,腐蚀电流密度降低,经过表面陶瓷化的镁合金耐腐蚀性能得到了提高。     

Determination of interfacial shear strength between the glass fiber and primary coating in double-coated optical fibers from mechanical strip forces

We propose a method of determining interfacial shear strength between the glass fiber and primary coating in double-coated optical fibers. A commercial stripper is used to mechanically strip the polymeric coatings. It consists of two hinged arms and a pair of blades with a semicircular bore. In the mechanical stripping process the relationship between the strip force and stripper displacement is measured. The interfacial shear strength between the glass fiber and primary coating is then determined from this relationship. The measured interfacial shear strength increases with the increasing stripping rate. It is found that measured results are compatible with theoretical results.     

玻璃包覆Fe79-xCox Si8 B13非晶合金微丝的磁性能

实验以熔融纺丝法制备的玻璃包覆Fe79-xCoxSi8B13非晶合金微丝为对象,分析了微丝成分、尺寸以及玻璃包覆层去除对微丝静磁性能的影响。研究结果表明,玻璃包覆Fe79-xCoxSi8B13非晶合金微丝存在明显的磁各向异性,微丝轴向为易磁化方向;随着Co含量的增加,微丝的饱和磁化强度先增大后减小,Co含量为10%的Fe69Co10Si8B13非晶合金微丝饱和磁化强度最高,为1323emu·cm-3;对于玻璃包覆Fe69Co10Si8B13非晶合金微丝,当芯丝半径与玻璃包覆层厚度比值k约小于0.5时,其轴向磁滞回线为近矩形,表现出大巴克豪森效应;微丝的轴向剩磁比随k值的增大而减小,而微丝径向剩磁比保持很小,仅0.03左右;微丝的轴向和径向矫顽力均随比值k的增大而减小;当芯丝半径为10.9μm、玻璃包覆层厚度为9.7μm(k为1.12)时,去除包覆层后微丝的轴向矫顽力降低30%、径向矫顽力降低11%;而轴向剩磁比降低33%、径向剩磁比降低67%。     

Electrophoretic deposition of bioglass reinforced zirconia for biomedical application

Ti-6Al-4V alloy is a bioinert material with low bioactive properties, which may hamper its bonding ability with body tissues that can be overcome by coating the metal with a bioactive glass layer, 45S5 reinforced zirconia. This coating can be deposited using an electrophoretic deposition process. In this study, a comparison is made between three types of coatings which are bioglass, pure zirconia and bioglass reinforced zirconia before and after heat treated. Mechanical evaluations using scratch tests and micro-hardness tests are conducted to evaluate the adhesion strengths and hardness properties of the coatings. The results show the presence of oxygen, and variations in the amounts of bioglass and zirconia, due to the activity of crystallization. X-ray diffraction confirms presence of all precursor elements in the coatings. The highest hardness value of 414 HV 2.942 is obtained for the sintered bioglass-zirconia composite coating, as compared to the hardness of bare titanium alloy of 266 HV 2.942. The highest adhesion strength of 1929 mN is also obtained for the bioglass-zirconia composite coating. These results show excellent performance for sintered bioglass-zirconia composite coating, making it a potential coating material for biomedical implants.     

Molecular characterization of glass fiber surface coatings for thermosetting polymer matrix/glass fiber composites

Model multi-component glass fiber sizings, with formulations based upon current patent disclosures, were prepared to model the full coating packages used in commercial glass fiber manufacture. The sizings consisted of silane coupling agent, film former, and emulsifying surfactant in water and were applied to glass fibers prepared directly from molten glass. Fibers were analyzed before and after acetone extraction. The analyses of the extract solutions, with the fiber analysis, were used to determine the quantity and quality of the physically and chemically adsorbed layers. It was found that all three species remain on the fiber after extraction and that both coupling agent and surfactant concentrations in the coatings are higher than in the applied sizing. The impact of these species on the polymer composite/glass fiber interphase is discussed.     

防脱碳涂料对30CrMnSiA热处理保护的研究

为了降低涂料成本,简化操作,以玻璃粉、滑石粉等为预原料,以虫胶为粘结剂,制备了一种用于30CrMnSiA钢材零件的热处理保护涂料,采用显微硬度测试及光学和扫描电镜观察等手段,研究涂料在热处理过程中对基体合金的保护作用。结果表明:该涂料不仅成本低廉、操作简单且具有优良的性能,在高温下能均匀分布在材料表面而不开裂,油淬后完全脱落,在930℃左右能有效减少材料表面的脱碳情况。材料表面全脱碳层消失,仅出现半脱碳层。脱碳层深度明显减少,最深距离由122.54μm减少至53.78μm,减少约1/2,具有较高应用价值。     

机械镀Zn-Al合金镀层的耐腐蚀性能研究

为了增强机械镀镀层的耐腐蚀性能,采用机械镀方法,以含铝5%(质量分数)的Zn-Al合金粉为原料,在Q235钢材基体表面制备了Zn-Al合金镀层。利用扫描电镜(SEM)表征了合金镀层的截面和断面形貌;采用极化曲线、电化学阻抗谱(EIS)分析了合金镀层在3.5%NaCl溶液中的电化学行为;通过中性盐雾腐蚀实验分析了合金镀层的耐蚀性,并采用XRD分析了镀层的盐雾腐蚀产物。结果表明,Zn-Al合金镀层由葫芦状的Zn-Al合金颗粒交错互嵌堆积而成,镀层颗粒之间以类似隼接的连接方式搭接“卡锁”;与机械镀Zn层相比,Zn-Al合金镀层的腐蚀电位正移了209 mV,腐蚀电流密度仅为纯Zn镀层的7.1%左右,极化电阻为纯Zn镀层的14倍;Zn-Al合金镀层的容抗弧半径明显大于纯Zn镀层的弧半径,且Q_dl较纯锌层减小;纯Zn镀层出现白锈和红锈的时间分别为24和362 h,而Zn-Al合金镀层出现白锈和红锈的时间为48和504 h。Zn-Al合金镀层的耐中性盐雾腐蚀性能明显优于纯Zn镀层,合金镀层对电荷转移具有更好的抑制作用,且Zn-Al合金镀层的腐蚀产物结构致密,可增强物理屏蔽功能。     

Sintering characteristics of nano-sized Ag–Pd–glass composite powders with high Pd content

Nano-sized Ag–Pd (50–50) alloy powders coated with Pb-based glass material with low and high glass transition temperature are directly prepared by high-temperature flame spray pyrolysis. Nano-sized Ag–Pd–glass composite powder is formed from the evaporated vapors by nucleation and growth process, and then glass material moves out to the outside of the powder by crystallization process of alloy. The thickness of the glass coating layer measured from the TEM image is 2.8 nm. The mass changes of the Ag–Pd alloy and Ag–Pd–glass composite powders in the TG analysis under 900 °C are 10.9 and 6.8%, respectively. Glass materials improve the uniformity and density of the Ag–Pd electrode layers by act as sintering agent and adhesion improvement. The Ag–Pd electrode formed from the composite powders with high glass transition temperature glass material has thin and uniform thickness. The specific resistances of the electrodes formed from the nano-sized Ag–Pd–glass composite powders are 0.27, 0.09, and 0.03 mΩ cm at firing temperatures of 700, 800, and 900 °C, respectively.