微束等离子喷涂羟基磷灰石涂层的体外生物活性研究

采用微束等离子喷涂(MPS)方法在Ti6A14V基体上制备羟基磷灰石(HA)涂层.利用扫描电镜(SEM)和x射线衍射(XRD)分析技术对HA涂层的表面形貌、相组成和结晶度进行表征,并通过模拟体液进行体外生物活性试验.结果表明,微束等离子喷涂制备的HA涂层具有一定粗糙度,存在气孔以及微裂纹.涂层存在热分解现象,涂层中含有HA、α-TCP、β-TCP和非晶相,不含CaO等杂质相.模拟体液试验表明,微束等离子喷涂工艺制备的HA涂层具有较好的生物活性和稳定性.涂层表面均有较大比例的CaP沉积层,且涂层整体保持完整,没有出现明显的剥离.     

工艺参数和热处理对纯钛表面激光熔覆原位合成羟基磷灰石涂层中物相组成的影响

使用CaCO3和CaHPO4混合粉末,在纯钛表面通过激光熔覆原位合成的方法制备羟基磷灰石(Ca10(PO4)6(OH)2,HA)涂层,研究了激光功率,扫描速度和热处理对涂层物相的影响,以期提高涂层中HA的含量。结果表明,低功率下,涂层的主要组成物相为磷酸四钙(Ca4(PO4)2O,TTCP),同时有少量的HA,α-磷酸钙(α-Ca3(PO4)2,α-TCP),CaO和CaTiO3;随功率的增加,涂层中的TTCP,HA和 CaO逐渐减少,只剩下α-TCP和CaTiO3。与功率相比,扫描速度对涂层物相的影响较小。当激光功率为400 W时,不同扫描速度下涂层的物相没有发生明显的变化,主要物相均为TTCP。将涂层在800 ℃下保温5 h,然后随炉冷却,可以使涂层中的TTCP和α-TCP全部转变为HA,进而得到含HA较多的涂层。     

烧结钕铁硼磁体等离子喷涂-晶界扩散氧化镝研究

目的 采用悬浮液等离子喷涂技术,在烧结Nd-Fe-B磁体表面制备结构完整、厚度可控、结合力较强的Dy2O3涂层,并通过晶界扩散提高Nd-Fe-B磁体的矫顽力.方法 制备Dy2O3悬浮液,在烧结Nd-Fe-B表面,利用悬浮液等离子喷涂技术制备Dy2O3涂层.利用激光粒度仪测试粉体粒度.采用光学显微镜、扫描电子显微镜(SE...     

CaCO3和CaHPO4·2H2O粉末配比对激光熔覆原位合成羟基磷灰石涂层的影响

使用碳酸钙(CaCO3)和二水磷酸氢钙(DCPD,CaHPO4·2H2O)混合粉末在纯钛表面利用激光熔覆的法制备羟基磷灰石HA,Ca5(PO4)3(OH)涂层,研究CaCO3和DCPD的质量比对涂层相组成和微观组织的影响。研究发现,CaCO3和DCPD之间的反应不仅在涂层中生成结晶度较高的HA,同时还生成了一定量的磷酸四钙(TTCP,Ca4P2O9),α-磷酸钙(α-TCP,α-Ca3(PO4)2),β-磷酸钙(β-TCP,β-Ca3(PO4)2)和焦磷酸钙(Ca2P2O7),且各相的含量与混合粉末的钙磷原子比有较大关系。HA只有在混合粉末的钙磷原子比大于1.54的情况下才能生成,其含量随钙磷原子比的升高而缓慢增加;当混合粉末的钙磷原子比达到2.0时,涂层中的HA的含量达到25%(质量分数),同时涂层中还存在大量的TTCP,因此制备的涂层需要进行一定的后续热处理以增加其中HA的含量。由于制备过程中粉末之间的反应会生成大量的气体,因此制备的涂层均为多孔结构,其中用钙磷原子比为2.0的混合粉末制备的涂层中,孔隙的尺寸在100~300μm之间。粉末钙磷原子比还能影响涂层的结合强度、孔隙率和裂纹数量。随钙磷原子比的升...     

等离子喷涂-水热合成羟基磷灰石涂层的体外稳定性

以CaHPO4为初始粉料，采用等离子喷涂一水热合成复合技术在Ti-6Al-4V基体上制备了羟基磷灰石(HA)涂层。用SEM，EDX和XRD分析涂层的形貌和组成，用电子拉伸机测定涂层的结合强度。并与等离子喷涂HA涂层做对比，研究了涂层的微观结构和结合强度及其在生理盐水中浸泡后的变化。结果表明：喷涂CaHPO4涂层由β-Ca2P2O7和α-Ca3(PO4)2组成，经水热合成，转化为高纯度和高结晶度的HA涂层；在生理盐水中浸泡1周～4周后，该HA涂层的溶解性和结合强度退化程度均低于等离子喷涂HA涂层，呈现较高的组织和力学稳定性。     

钛基Ca-P涂层相组成的定量分析及降解性能研究

采用大气等离子喷涂技术,在纯钛表面喷涂制备钙磷(Ca-P)涂层,分析两种喷涂工艺下形成的两种特殊形貌晶体的显微结构和元素组成,利用XRD定量分析涂层的相组成及结晶度,并在人体模拟液(SBF)中对涂层的降解性能进行研究。结果表明:在喷涂功率为22kW、喷枪移动速率为400mm/s时涂层表面形成大量方棱状的焦磷酸钙(Ca2P2O7)晶体,结晶度为4.61%,而在喷涂功率为26kW、喷涂距离为300mm/s时则形成大量花瓣状的磷酸四钙(Ca4P2O9)晶体,结晶度为6.02%,喷涂粉体粒度较小使得两种涂层中HA结晶度都较小;生物降解性能研究显示,两涂层降解反应都是由剧烈到平缓的过程,但含Ca2P2O7晶体涂层的降解速率小于含Ca4P2O9晶体的涂层。     

医用镁合金表面激光重熔羟基磷灰石涂层

为提高医用镁合金的表面耐蚀性和生物相容性,采用等离子喷涂和激光重熔复合技术在镁合金表面制备羟基磷灰石(HA)生物涂层。研究结果表明,所制备的羟基磷灰石涂层为短杆状堆积结构,主要由HA和β-TCP相组成;涂层的弹性模量约为50 GPa,较已临床应用的医用金属材料显著降低,显微硬度约为455 HV,具有较好的耐磨性。涂层在模拟体液中具有很好的耐蚀性,在腐蚀12 d后涂层表面形貌仍然较完整,无腐蚀孔洞出现。钙磷沉积实验结果表明,涂层表面形成一层新的生物磷灰石层,表明涂层具有较好的骨诱导性。     

纳米氧化铝悬浮液浓度对等离子喷涂涂层构建的影响

采用纳米氧化铝(粉末直径约20nm)悬浮液大气等离子喷涂技术(SPS)制备了含纳米结构的涂层.采用理论计算、SEM分析的方法研究纳米氧化铝悬浮液浓度对涂层构建的影响.结果表明,纳米氧化铝悬浮液浓度对粒子直径的分布,喷涂悬浮液所需的等离子能量,涂层表面粗糙度以及涂层显微结构都有显著的影响,降低悬浮液浓度有利于获得精细的涂层结构,但喷涂效率降低,优化的悬浮液浓度(质量分数,%)在5～10.     

等离子喷涂氧化铝基复合涂层研究进展

随着等离子喷涂技术的发展,等离子喷涂氧化铝基复合涂层在防腐蚀、耐磨损和航天航空等领域得到了广泛应用。首先简要介绍了新型等离子喷涂技术(激光等离子喷涂、悬浮液等离子喷涂和超音速等离子等)和主要喷涂工艺参数(喷涂功率、送粉方式和喷涂距离等),然后从改善涂层耐腐蚀性能的角度出发,阐述了第二相、喷涂工艺参数和后处理工艺对涂层气孔率的影响及与涂层耐腐蚀性能的关系。重点分析了硬度、喂料特征和激光熔覆技术对氧化铝基复合涂层耐磨损性能的影响,详述了影响硬度的因素,以及喷涂粉末特征和激光熔覆处理对复合涂层微观结构的影响。在电磁波吸收性能研究方面,论述了吸收剂含量、涂层厚度和多种电磁波吸收剂匹配以及喷涂参数的调整对等离子喷涂氧化铝基复合涂层吸波性能的影响。最后对以等离子喷涂技术制备性能更加优异的氧化铝基复合涂层提出了展望。     

超音速悬浮液火焰喷涂HA涂层的组织及力学性能

以纳米羟基磷灰石(HA)颗粒为原始粉末,通过超音速悬浮液火焰喷涂(HVSFS)法在316L不锈钢基体上制备纳米结构HA涂层。研究了丙烷流量对纳米结构HA涂层相结构、微观结构及力学性能的影响。结果表明:纳米结构HA涂层相结构与丙烷流量相关;该涂层表面由部分熔化粒子形成的粗糙多孔结构组成,涂层与基体界面结合良好;该涂层的显微硬度随丙烷流量(1000～1500 L/h)增加从40.9 HV0.025提高到133.3 HV0.025,弹性模量从3.9 GPa提高到4.9 GPa,涂层磨损率从0.67 mg/(N·m)降低到0.13 mg/(N·m),涂层磨损表面主要呈犁沟与剥落特征。超音速悬浮液火焰喷涂可获得相结构不分解的纳米结构HA涂层,且该涂层的力学性能随丙烷流量的增加而提高。     

Fabrication and Characterization of Suspension Plasma-Sprayed Fluoridated Hydroxyapatite Coatings for Biomedical Applications

Fluoridated hydroxyapatite (FHA) coatings were prepared on a Ti substrate using a suspension plasma spraying technique. The crystalline phases and chemical compositions of the coatings were characterized using x-ray diffraction, Fourier transform infrared spectroscopy, and x-ray photoelectron spectroscopy. The analysis confirmed that the coating consisted of an FHA phase. The corrosion behavior in simulated body fluid was studied using potentiodynamic polarization tests, and the results indicated that the FHA coating greatly enhanced the corrosion resistance of the Ti substrate. The chemical stability of the FHA coatings was assessed by evaluating the release of Ca²⁺ ions. The results indicated that the substitution of fluorine into the hydroxyapatite (HA) structure had a positive effect on the dissolution resistance of the HA. The antibacterial activity was investigated using a surface-plating method; the results revealed that the antibacterial activity of the FHA coating was greater than that of the pure HA coatings. During cell culture tests, the FHA coating did not exhibit cytotoxicity toward the osteoblast cell line, and the cell proliferation was comparable with that of the HA coatings. The antibacterial activity and cell culture results suggested that the plasma-sprayed FHA coating possesses good antibacterial qualities, but is biocompatible with osteoblasts. The promising features of the FHA coating render it suitable for orthopedic and dental applications.     

悬浮液等离子喷涂制备FHA/CS复合涂层

目的 采用悬浮液等离子喷涂技术（SPS）在纯钛表面制备氟代羟基磷灰石/硅酸钙（FHA/CS）生物复合涂层。方法 利用X射线衍射仪（XRD）、傅里叶红外光谱仪（FT-IR）、扫描电子显微镜（SEM）及能谱仪（EDS）对复合涂层的物相组成、组织结构和显微形貌进行分析。通过动电位极化测试和体外生物活性测试,分析复合涂层在模拟体液（SBF）中的腐蚀行为和类骨磷灰石形成能力。通过电感耦合等离子体光谱仪（ICP）分析涂层中Ca2+的释放行为,评估复合涂层的化学稳定性。采用划痕法表征涂层的结合强度。结果 SPS制备的复合涂层具有粗糙的表面和层片堆叠结构。涂层中FHA和CS两相分布均匀,结晶性良好。复合涂层临界载荷达到111.43 N,比单一FHA涂层提高62.5%。与纯钛相比,涂层样品具有较高的腐蚀电位（Ecorr）和较低的腐蚀电流密度（Jcorr）。在SBF溶液中浸泡3天,涂层样品表面被类骨磷灰石完全覆盖。ICP结果表明,复合涂层中Ca2+释放速率低于单一CS涂层。结论 通过SPS在纯钛表面制备的FHA/CS复合涂层具有良好的生物活性、耐腐蚀性能和与基体的结合强度,复合涂层中FHA组分的存在有利于提高涂层的化学稳定性。     

Enhancing Biocompatibility and Corrosion Resistance of Ti-6Al-4V Alloy by Surface Modification Route

Titanium (Ti) and its alloys are widely used as candidate materials for biomedical implants. Despite their good biocompatibility and corrosion resistance, these materials suffer from corrosion after implantation in biological environments. The aim of this research work is to study the effect of two coatings on biocompatibility and corrosion behavior of Ti-6Al-4V biomedical implant material. Hydroxyapatite (HA) and hydroxyapatite/titanium dioxide (HA/TiO₂) coatings were thermal-sprayed on Ti-6Al-4V substrates. In the latter case, TiO₂ was used as a bond coat between the substrate and HA top coat. The corrosion behavior of coated and un-coated samples in Ringer’s solution was studied by potentiodynamic and linear polarization techniques. Before and after corrosion testing, XRD and SEM/EDS techniques were used for the analysis of phases formed and to investigate microstructure/compositional changes in the coated specimens. The cellular response was analyzed by the MTT (microculture tetrazolium) assay. The results showed that both the HA, as well as, the HA/TiO₂ coatings significantly increased the corrosion resistance of the substrate material. The HA coating was found to be more biocompatible as compared to the un-coated and HA/TiO₂-coated Ti-6Al-4V alloy.     

热浸Zn-Ti合金镀层的耐腐蚀性能

为了抑制热镀锌过程中因含硅活性钢引起的镀层超厚生长,采用在纯锌浴中加Ti的方法,研究了热浸Zn-Ti合金镀层的耐蚀性能.采用浸泡腐蚀、电化学极化、交流阻抗以及X射线光电子能谱等方法,研究了热浸Zn-Ti合金镀层的耐蚀性能.结果表明:Zn-Ti舍金镀层在5%NaCl溶液中的自发腐蚀倾向小于Zn镀层,其极化电阻和交流阻抗增大,腐蚀电流密度减小,耐蚀性能提高.Zn-Ti镀层表面形成的氧化膜由ZnO和TiO2组成.Zn-Ti合金镀层的耐腐蚀性能优于纯锌镀层是由于在镀层表面形成了更加稳定的TiO2膜.     

Fe基非晶/纳米晶涂层的微结构及其在H2O2溶液中的腐蚀性能

为研究强氧化环境中,显微结构和相组成对Fe基非晶/纳米晶复合涂层的腐蚀腐蚀性能的影响,采用大气等离子喷涂(APS)技术,在1Cr18Ni9Ti不锈钢基体上喷涂制得具有不同微结构和相组成的Fe基非晶/纳米晶的复合涂层。采用XRD、SEM、TEM和DSC等检测方法对涂层的组织和相组成、晶化行为、晶化程度、内部的孔隙等微观结构进行表征。采用电化学法研究具有不同微结构和相组成的涂层在30%H₂O₂ (质量分数,下同)溶液中的腐蚀行为,探讨Fe基非晶/纳米晶复合涂层在强氧化环境中的腐蚀机理。研究表明,Mo₃Si和Fe₅Si₃相的形成使得涂层耐腐蚀性能明显降低。     

Corrosion Resistance of Superhydrophobic Mg-Al Layered Double Hydroxide Coatings on Aluminum Alloys

A superhydrophobic surface was successfully constructed to modify the layered double hydroxide (LDH) coatings on aluminum alloy using stearic acid. The characteristics of the coatings were investigated using SEM, XRD, FT-IR and XPS. The corrosion resistance of the prepared coatings was studied using potentiodynamic polarization and electrochemical impedance spectrum. The results revealed that the superhydrophobic surface considerably improved the corrosion-resistant performance of the LDH coatings on the aluminum alloy substrate. The formation mechanism of the superhydrophobic surface was proposed.     

Interface activation and surface characteristics of Ti/TiN/HA coated sintered stainless steels

Interface activation and surface characteristics of Ti/TiN/HA film coated sintered stainless steels (SSS) have been investigated by electrochemical and biocompatibility tests. HA (hydroxyapatite), Ti, and Ti/TiN film coatings were applied using electron-beam deposition method (EB-PVD). Ti, Ti/TiN, and Ti/TiN/HA film coated surfaces and layers were investigated by SEM and XPS. The coated films showed micro-columnar structure, and Ti/TiN/HA films were denser than Ti or HA-only film. The corrosion resistance of the HA coating was similar to that of Ti/TiN/HA film coating when Cu content reached 4 wt.%, but the corrosion resistance of the HA coating decreased when Cu content increased from 4 wt.% in 0.9% NaCl solution. Therefore, HA-only coating could ensure corrosion resistance when Cu content does not exceed 4 wt.%. The results of biocompatibility tests of SSS on dogs showed that bone formation and biocompatibility were favorable when Cu content did not exceed 4 wt.%. The biocompatibility with bone was generally favorable in Ti/TiN/HA film coating and HA-only coating, while bone formation was somewhat faster for the HA film coated surface than for the Ti/TiN/HA film coating. Also, good cell growth and osseointegration without toxicity were observed.     

Preparation of Al-based Amorphous/Nanocrystalline Composite Coating on Mg-based Alloys Precipitated by Arc Spraying Process

The Al-based amorphous and nanocrystalline composite coatings with the composition of Al-Ni-Y-Co and Al-Ni-Mm-Fe were prepared on AZ91 Mg-based alloys by high velocity arc spraying technique(HVAS).The structure character of the coatings indicates that coatings contain the mixture of amorphous phases and crystalline and there are both less than 2%porosity.The electrochemical tests of the coatings and the substrate were studied.The coatings show the passivation ability during polarization,but AZ91 Mg-based alloys show little passivation.The corrosion current density of the coatings is lower than that of AZ91 Mg-based alloys.The results show that the coatings have an excellent corrosion resistance for AZ91 Mg-based alloys in 5 wt%NaCl solution.     

Densification of plasma-sprayed titanium and tantalum coatings

Thermal spraying of corrosion- resistant coatings of titanium and tantalum is difficult; dense coatings are not produced, and oxidation of these metals increases coating porosity. In this study, oxidation during plasma spraying was reduced with a shrouding system. Porosity and oxide content also were minimized by optimizing the spraying parameters. After optimization, the coatings still had open porosity and thus were incapable of protecting the substrate material against corrosion in water solutions containing 3 % NaCl. Therefore, posttreatments for improvement of corrosion resistance were studied. Electron beam fusion produced corrosion resistance equal to or better than that of bulk commercial samples of titanium and tantalum.     

Hot Corrosion Behavior of a High Velocity Arc-Sprayed Fe-Cr-B-C Coating

A Fe-Cr-B-C coating was prepared by electric arc spraying process to prevent the boiler tubes from hot corrosion at elevated temperatures.A hot corrosion resistance test was conducted in a mixed molten salt of Na2SO4 and K2SO4(7:3)at 700 ℃for a total period of 156 h.The microstructure and phases of the coatings before and after exposed to the hot corrosion were investigated by scanning election microscopy(SEM),optical microscopy(OM)and X-ray diffraction(XRD).The hardness and porosity were analyzed.The hot corrosion behavior of the coatings was examined by the measurement of corrosion mass gain and the observation of corrosion morphology.The results show that some splats of particles are formed on flat substrate surfaces and the coatings have a dense typical layer structure of electric arc thermally spraying deposits.Some amorphous phase exist in the coating.The coatings have an excellent resistance to hot corrosion.The formation of oxides of chromium on the exposed surface may be contributing better resistance to hot corrosion.The corrosion of the coatings follows the oxidation and sulfidation mechanism.