Effect of Y_2O_3 Content on Microstructure of Gradient Bioceramic Composite Coating Produced by Wide-Band Laser Cladding

To eliminate thermal stress and cracks in the process of laser cladding, a kind of bioceramic coating with gradient compositional design was prepared on the surface of Ti alloy by using wide-band laser cladding. And effect of Y2O3 content on gradient bioceramic composite coating was studied. The experimental results indicate that adding rare earth can refine grain. Different rare earth contents affect formation of HA and β-TCP in bioceramic coating. When the content of rare earth ranges from 0.4% to 0.6%, the active extent of rare earth in synthesizing HA and β-TCP is the best, which indicates that “monosodium glutamate” effect of rare earth plays a dominant role. However, when rare earth content is up to 0.8%, the amount of synthesizing HA and β-TCP in coating conversely goes down, which demonstrates that rare earth gradually losts its catalysis in manufacturing HA and β-TCP.

Characteristics of a multi-component MgO-based bioceramic coating synthesized in-situ by plasma electrolytic oxidation

Plasma electrolytic oxidation(PEO)has held great potential for the advancement of biodegradable implants,as it helps in developing porous bioceramic coatings on the surface of magnesium alloys.In this research work,MgO-based bioceramic coatings containing the Si,P,Ca,Na,and F elements have been successfully fabricated on an AZ31 magnesium alloy plate utilizing the PEO method.The characteristic current-voltage behavior of the samples during the process was surveyed in an electrolyte containing Ca(H_(2)PO_(4))_(2),Na_(2)SiO_(3)·9H_(2)O,Na_(3)PO_(4)·12H_(2)O,NaF,and KOH with a pH of 12.5 and electrical conductivity of 20 mS/cm^(-1).The results revealed that applying a voltage of 350-400 V(that is 50-100 V higher than the breakdown limit)could greatly facilitate the synthesis of a PEO ceramic coating with fewer defects and more uniform morphology.The resulting coating was a compositionally graded bioceramic layer with a thickness in the range of 3.5±0.4 to 6.0±0.7µm,comprising the above-mentioned elements as promising bioactive agents.The synthesized ceramic features were investigated in terms of the elemental distribution of components through the thickness,which indicated a gradual rise in the Si and P contents and,conversely,a decline in the F content towards the outer surface.The growth mechanism of the PEO coating has been discussed accordingly.

Laser surface coating of RE bioceramic layer on TC4

A layer of premixed CaHPO 4·2H 2O CaCO 3 Y 2O 3 powders stuck on pretreated surface of Ti 6Al 4V alloy substrate was successfully transformed into a composite of rare earth bioceramic coating by laser synthesizing and cladding only once. The microstructure and properties of the coating material were introduced. The titanium alloy with bioceramic coating on one side were implanted into the femur bone and thigh muscles of adult Mongrel dogs for testing its biocompatibility. The results of implantation experiments show that the microstructure of the coating material is static, the bonding properties between coating and substrate are better. The bioceramic coating had not toxicity side effectiveness on the body and there is a better compatibility of osteoconducton. No effect of the coating material on the bio activity of osteoblast and osteoclast was found.

Dynamics of Gradient Bioceramic Composite Coating on Surface of Titanium Alloy by Wide-Band Laser Cladding

The gradient bioceramic coating was prepared on the surface of titanium alloy using wide-band laser cladding.The dynamics of gradient bioceramic composite coating containing hydroxyapatite(HA)prepared with mixture of CaHPO4·2H2O and CaCO3 under the condition of wide-band laser was studied theoretically.The corresponding mathematical model and its numerical solution were presented.The examination experiment showed that HA bioceramic composite coatings can be obtained by appropriately choosing wide-band laser cladding parameters.The microstructure and surface morphology of HA bioceramic coating were observed by SEM and X-ray diffraction.The experimental results showed that the bioceramic coating is composed of HA,β-TCP,CaO,CaTiO3 and TiO2.The surface of bioceramic coating takes coral-shaped structure or short-rod piled structure,which helps osteoblast grow into bioceramic and improves the biocompatibility.

Influence of Electrolyte Composition on the Calcium-Phosphorus compound Coating on Titanium Substrate by Micro-arc Oxidation

The compound bioceramic coating containing calcium (Ca) and phosphorus (P) on titanium alloy substrate was prepared by means of micro-arc oxidation (MAO) treatment. The results show that under the different electrolyte the coating with the color of gray or black and surface morphology of cauliflower or honeycomb, where Ca content and P contain can attain 30% and 20% respectively, can be obtained. Meanwhile, the influences of electrolyte temperature, current density and discharge time on morphology and thickness of coating are also discussed here.

Study on High Temperature Corrosion Performance and Protective Coatings of Mo-containing Intermetallic Alloy IC6

Oxidation and hot corrosion behaviors of Ni3Al-Mo (IC6) alloy were studied. Surface protective coatings were also developed for the engineering application of the alloy. The sputtered NiCrAlY coating may greatly improve the oxidation and hot corrosion resistance of IC6 alloy by forming a protective Al2O3 scale, and the coating shows little effect on the mechanical properties of IC6 alloy.

Graphit-ic与Dymon-ic薄膜的结构与性能研究

用全封闭非平衡磁控溅射技术制备Graphit-ic和Dymon-ic薄膜。利用SEM,AFM,TEM,XRD,纳米压痕仪,高温摩擦磨损试验机等研究了薄膜的微观结构、表面形貌、显微硬度以及摩擦磨损性能。结果表明:Graphit-ic薄膜和Dymon-ic薄膜均由非晶组织构成,薄膜均匀、致密,粗糙度小;Graphit-ic薄膜的显微硬度低于Dymon-ic薄膜;同时,在干摩擦条件下,Graphit-ic薄膜和Dymon-ic薄膜与GCr15钢球对磨时显示出良好的耐磨减摩性能,Graphit-ic薄膜的摩擦系数低于Dymon-ic薄膜,但其比磨损率却高于Dymon-ic薄膜。

纳米TiC颗粒对Ni-TiC复合镀层组织与性能的影响

采用双脉冲复合电镀技术,在瓦特型镀液中,制备含微-纳米TiC颗粒的Ni基复合镀层。研究镀液中纳米TiC添加量对复合镀层微观形貌、组织结构、硬度、摩擦和抗氧化性能的影响。结果表明:镀液中添加纳米TiC后,Ni-TiC复合镀层表面出现团聚、致密度降低,复合镀层的组织为Ni和TiC;随镀液中纳米TiC添加量的增加,复合镀层的显微硬度呈先增后降的趋势,而摩擦因数则先降后升;当纳米TiC颗粒添加量为6.0g/L时,复合镀层显微硬度最大,为445HV,摩擦因数较小,为0.22,磨损机制以磨料磨损为主;在900℃,100h氧化条件下抗氧化性能最佳,氧化增重为6.828mg/cm^2,为微米复合镀层的0.5倍。

IC-6高温合金的氧化性能与防护

测定了IC - 6高温合金在 90 0℃～ 110 0℃的氧化动力学曲线 .结果表明 :90 0℃ ,IC - 6合金的氧化膜主要由α-Al2 O3 、NiAl2 O4 和NiO构成并含有少量的NiMoO4 和MoO2 .10 5 0℃和 110 0℃氧化时 ,IC - 6合金表面生成了挥发性很强的MoO3 ,发生了氧化失重 .IC - 6合金上沉积NiCoCrAlY涂层后 ,90 0℃时 ,涂层的氧化膜主要为α-Al2 O3 ;10 5 0℃时 ,氧化膜主要为α -Al2 O3 和Cr2 O3 ,大大改善了合金的抗氧化性 .110 0℃时 ,氧化膜主要由α-Al2 O3 、NiAl2 O4 和NiO构成 ,涂层虽然有一定的保护性 ,但效果不如 90 0℃和 10 5 0℃时显著 .形成以α -Al2 O3 和Cr2 O3 为主的氧化膜是使合金沉积NiCoCrAlY涂层后抗氧化能力大大提高的直接原因 .

低温热处理对Graphit-iC类石墨碳膜组织结构及耐磨性的影响

应用拉曼光谱(Raman)等测试方法分析了不同热处理温度对PVD技术制备的Graphit-iC类石墨碳膜涂层的组织结构、显微硬度、结合强度和磨损率的影响规律。结果表明:随温度升高,涂层发生sp3→sp2结构转变,相对强度比I_D/I_G增加,石墨化倾向增大;涂层磨损率在25～250℃温度区间内保持较低的水平,当温度继续上升后表面显微硬度及结合力降低,磨损率显著增大,耐磨性降低。

两种IC-6高温合金防护涂层的氧化行为

研究了IC - 6高温合金及其防护性涂层NiCrAlY和NiCoCrAlY涂层在 90 0～ 110 0℃时的氧化 .结果表明 :沉积NiCrAlY和NiCoCrAlY涂层后大大改善了IC - 6合金的抗氧化性 .在 10 0 0和 110 0℃时 ,NiCrAlY涂层的抗氧化性优于NiCoCrAlY涂层 .90 0℃时 ,NiCrAlY涂层氧化膜主要是α -Al2 O3 ,同时还含有少量的Cr2 O3 ;而NiCoCrAlY涂层氧化膜为单一的α-Al2 O3 ,但由于NiCoCrAlY涂层表面氧化膜不致密 ,降低了涂层的抗氧化性 .10 0 0℃氧化时 ,NiCrAlY涂层和NiCoCrAlY涂层的氧化膜主要由α -Al2 O3 和Cr2 O3

Zinc-doped hydroxyapatite-zeolite/polycaprolactone composites coating on magnesium substrate for enhancing in-vitro corrosion and antibacterial performance

This work is focused on developing zinc-doped hydroxyapatite-zeolite(Zn HA-Zeo)and polycaprolactone(PCL)composite coatings on magnesium(Mg)substrate to improve the corrosion resistance and antimicrobial properties.Dip-coating technique was used to coat Zn HA-Zeo/PCL on the Mg substrate at room temperature.The samples were subjected to field emission scanning electron microscopy(FESEM),X-ray diffraction(XRD),Fourier transform infrared(FTIR),energy dispersive X-ray spectroscopy(EDX)and antimicrobial potential.Results demonstrated that composite coatings consist of HA,scholzite,zeolite,and PCL phases.EDX spectra indicated the presence of calcium(Ca),silicon(Si),aluminum(Al),zinc(Zn),phosphorus(P)and oxygen(O).The composite surface appeared in spherical-like microstructure on coating with thickness ranging 226-260μm.Zinc-doped HA-Zeo composite coating had a high corrosion resistance and provided sufficient protection to the Mg surface against galvanic corrosion.Doped Zn HA-Zeo coating samples exhibited superior disc inhibition by confirming antimicrobial activity against the E.coli as compared to HA-Zeo sample.Altogether these results showed that the Zn HA-Zeo coatings not only improved the corrosion resistance,but also enhanced the antimicrobial property and hence they can be used as suitable candidates for implant applications.

Synthesis of Niobium Doped ZnO Nanoparticles by Electrochemical Method: Characterization, Photodegradation of Indigo Carmine Dye and Antibacterial Study

Niobium doped Zincoxide nanoparticles has been synthesized through electrochemical method and characterized by UV-Visible spectroscopy, IR Spectroscopy, SEM, XRD, ICPMS and EDAX data. The UV-Visible spectroscopy result reveals that the band gap energy of ZnO/Nb2O5 nanoparticles to be 3.8 eV. The XRD results show that the crystallite size is to be 31.9 nm. The ICPMS data indicate the presence of 3,3461,328 counts of 93 Nb and 577,906,390 counts of 66 Zn. An improvement in the photocatalytic degradation of Indigocarmine dye (IC) in comparison to commercially available pure ZnO was observed. The photodegradation efficiency for ZnO/Nb2O5 and ZnO were found to be 97.4% and 52.1% respectively. The enhancement in photocatalytic activity of ZnO/ Nb2O5 was ascribed to the extended light absorption range and suppression of electron hole pair recombination upon Nb loading. The antibacterial activity of ZnO/Nb2O5 nanoparticles was investigated. These particles were shown to have an effective bactericide.

IC封装钎焊表面变色原因探讨

本文对IC封装钎焊位置变色现象进行了形貌和成份分析,认为变色的主要原因是Ni镀层有针孔或空洞,根本原因在电镀工艺。

高性能涂层微钻在IC封装基板精密微孔加工应用研究

研究微钻不同涂层种类对IC封装基板加工性能及效率的影响。针对几种典型难加工IC封装基板,通过对IC封装基板机械钻孔加工难点、刀具失效机理、不同高性能涂层微钻的性能特点进行分析,设计不同高性能涂层微钻,获得了IC封装基板尤其是难加工封装基板的钻孔品质保障、效率提升、刀具寿命提高方面的有效解决方案。研究结果显示,针对刀具磨损极大的高填料封装基板,金刚石涂层可有效改善微钻的耐磨性能,相对于未涂层微钻和其他类型涂层微钻,刀具寿命显著提升。类金刚石涂层因其较低摩擦系数,有利于切屑的快速排出、降低了加工温度和减小了切削力。对厚径比大、排尘困难的封装基板,如FC-BGA用厚芯板的微孔加工,能有效改善孔壁粗糙度,提升孔位精度,降低断刀率,大幅提升钻孔品质;对于较薄的封装基板如CSP板的微孔加工,能够降低断刀率、增加叠板数量,提升加工效率。

风力发电机叶片防除冰涂层(二):温升数值计算及防除冰性能

针对电热超疏水涂层覆冰过程中表现出的三类不同冰层形貌,该文建立了电加热融冰数值计算模型,并对仿真计算结果进行了相应的试验验证,验证结果与仿真结果基本一致,该模型能有效模拟融冰过程和温度分布。临界融冰功率的计算结果表明,电热超疏水涂层融冰所需功率大于非超疏水电热涂层,尤其在乳突状冰层出现后,融冰功率将大幅增加。电热超疏水涂层防冰试验结果表明,在雨凇覆冰环境中,超疏水性能单独作用时,叶片在覆冰前期能延缓覆冰;电热性能与超疏水性能共同作用时,叶片无覆冰形成。电热超疏水涂层用于风力发电机防覆冰具有较好的效果,但用于覆冰后的融冰时将需要更多的能量。

莫米松糠酸酯高特异性抗体制备及酶联免疫分析方法

莫米松糠酸酯(mometasone furoate,MF)是一种常见的糖皮质激素。为快速、便捷地监控MF的滥用情况,制备了MF单克隆抗体并建立了其竞争酶联免疫检测方法。将氨氧乙酸分别连接至MF和莫米松二糠酸酯(mometasone difuroate,MDF),合成了免疫半抗原和包被半抗原。免疫半抗原以活泼脂法连接钥孔血蓝蛋白获得全抗原,通过免疫小鼠、细胞融合及筛选获得能够稳定分泌抗MF单克隆抗体的细胞株,制备并纯化了抗体。该抗体的主要识别区域为MF的五元环区域,因此不和常见的64种糖皮质激素发生交叉反应。建立了基于异源包被的MF间接竞争酶联免疫检测法,其半抑制浓度(IC_(50))为1.2 ng/mL,对肌肉和肝脏的最低检出限分别为0.52μg/kg和0.59μg/kg。灵敏度相比于同源包被提升了20倍。使用60%甲醇水溶液提取动物组织的添加回收率为70%~82%。该方法能有效应用于动物组织中MF的快速筛查。

超疏水材料及其涂层的研究进展

随着科技的飞速发展,各种新型材料层出不穷,其中超疏水材料及其涂层因其卓越的抗水特性,在医学、建筑、纺织等众多领域展现出广阔的应用前景,逐渐成为近年来备受关注的研究热点和前沿。因此,深入研究超疏水材料及其涂层的理论和制备方法显得尤为重要,这不仅有助于科研人员更好地理解和掌握此类材料的特性和应用,为其进一步的研究提供基础理论支撑,同时也有助于推动相关领域的技术创新和发展。详细阐述了超疏水材料的相关理论,包括其分子结构、表面能和润湿性等基础理论知识。同时,系统探讨了其制备方法,包括采用蜡处理法、光刻技术法、层层自组装法、电化学和化学物理复合法等各种方法制备具有超疏水性能的表面材料,并对各种方法进行比较和评价。最后,详细介绍了超疏水材料的性能及其在不同领域的应用,包括其在自清洁、防腐、防冰和防雾等方面的功能,为读者提供参考和借鉴。然而,超疏水材料及其涂层在实际应用中仍存在一些不足。对这些问题进行了探讨,分析其存在的问题和挑战,同时对未来发展进行了展望,为相关领域的研究提供一定的参考思路。