Formation and Characterization of Hydroxyapatite Coating Prepared by Pulsed Electrochemical Deposition

采用交流脉冲沉积法在AZ91D镁合金表面合成了羟基磷灰石涂层。考察了交流脉冲电压、沉积时间及电解液添加剂等电化学沉积参数对羟基磷灰石涂层的形貌、微观结构、元素组成及电化学性能的影响。结果表明,当脉冲电压为110 V时,纳米级别的羟基磷灰石涂层表面更为均匀,孔隙度更小,且其XRD的特征衍射峰更为突出。当电解液中添加了NaN O3和H2O2后,羟基磷灰石颗粒和涂层表面形貌均得到优化;同时,极化曲线和交流阻抗测试结果表明该涂层在模拟体液中的耐蚀性能提高。浸泡实验结果表明,该涂层有利于诱导羟基磷灰石的形成,从而提高涂层的生物活性。     

交流脉冲电沉积羟基磷灰石涂层的制备及其性能(英文)

采用交流脉冲沉积法在AZ91D镁合金表面合成了羟基磷灰石涂层。考察了交流脉冲电压、沉积时间及电解液添加剂等电化学沉积参数对羟基磷灰石涂层的形貌、微观结构、元素组成及电化学性能的影响。结果表明,当脉冲电压为110 V时,纳米级别的羟基磷灰石涂层表面更为均匀,孔隙度更小,且其XRD的特征衍射峰更为突出。当电解液中添加了NaN O3和H2O2后,羟基磷灰石颗粒和涂层表面形貌均得到优化;同时,极化曲线和交流阻抗测试结果表明该涂层在模拟体液中的耐蚀性能提高。浸泡实验结果表明,该涂层有利于诱导羟基磷灰石的形成,从而提高涂层的生物活性。     

微束等离子喷涂氧化锆增韧羟基磷灰石复合涂层

采用微束等离子喷涂方法,在Ti-6Al-4V基体上制备了羟基磷灰石 氧化锆(70HA-30ZrO2,质量分数,%)复合涂层.将复合涂层置于模拟体液中分别浸泡了3,7,14,28 d并观察表面磷灰石的生长情况以评价涂层生物活性.采用扫描电镜(SEM)和X射线衍射(XRD)分析技术对涂层浸泡前后的表面形貌和相组成进行了研究.结果表明,涂层中ZrO2主要以立方相存在;喷涂过程中羟基磷灰石(HA)出现了一定的分解,产生大量的α-Ca3(PO4)2杂质相.HA涂层熔化效果很好,但涂层中有未熔化的ZrO2颗粒.涂层在模拟体液中浸泡28 d后表面可以形成磷灰石,说明涂层具有很好的生物活性.     

医用镁合金ZrO2陶瓷膜制备及其骨生物活性研究

为了提高医用镁合金的耐蚀性及骨生物活性,分别在锆盐体系和硅酸盐体系溶液中,采用微弧氧化技术在镁合金表面制备具有生物活性的陶瓷膜。利用X射线衍射仪分析了陶瓷膜的相成分,并通过Hank’s体液模拟试验研究了陶瓷膜表面形貌演变和Ca、P等元素的含量变化。研究结果表明:锆盐体系溶液中制备的陶瓷膜主要由ZrO2和MgF2组成;硅酸盐体系溶液中制备的陶瓷膜主要由MgSiO3和MgO组成。在模拟体液浸泡过程中,陶瓷膜未发生腐蚀,表明对镁合金基体具有良好的防护作用。在体液浸泡7 d至14 d,陶瓷膜表面有团状物形成;浸泡21 d后,表面出现蠕虫状的羟基磷灰石形貌;同时,陶瓷膜表面的Ca、P元素含量随浸泡时间延长逐渐增加;其中,锆盐体系溶液中制备陶瓷膜表面的Ca/P比达到1.445,接近羟基磷灰石中的Ca/P比(1.67)。     

预钙化处理提高钽的表面生物活性

为提高钽的生物活性,对钽进行了NaOH溶液碱处理,利用模拟体液(SBF)浸泡实验探索碱处理的最佳浓度。碱处理后的钽又分别在CaCl2溶液和K2HPO4溶液中进行预钙化处理。钽经过0.7mol/L的碱处理后,在SBF中浸泡2周,表面即可被羟基磷灰石覆盖。经预钙化处理后,钽在SBF中浸泡4天,表面即可覆盖一层羟基磷灰石,说明预钙化大幅提高了钽的生物活性。其机理是预钙化处理可使样品表面迅速完成钙磷化合物的形核,浸入SBF以后羟基磷灰石可以迅速长大。     

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。     

镁基磷酸钙类/壳聚糖生物复合材料的制备

采用化学沉积法在AZ91镁合金微弧氧化陶瓷膜表面制备磷酸钙类/壳聚糖复合膜层,并用XRD,SEM,EDS和等离子体热电光谱(ICP)仪等对复合膜层化学组成及结构进行表征。XRD测试结果显示,该生物复合涂层是由磷酸钙(TCP)、磷酸氢钙(DCPD)及少量的羟基磷灰石(HA)所构成。壳聚糖的引入使磷酸钙复合膜层表面形貌发生明显变化,与未加入壳聚糖相比,DCPD和TCP的含量明显增加。采用电化学测试方法及模拟体液浸泡试验评价该薄膜的耐蚀性能。结果显示,该复合涂层生物性能稳定,能够提高镁合金的抗腐蚀性能。     

微弧氧化镁表面钙磷生物涂层的制备及性能

为改善镁合金的骨植性能,采用微弧氧化处理和电沉积钙磷涂层相结合的方法在纯镁表面制备具有生物活性的复合涂层,研究了复合涂层在模拟体液和细胞培养液中的组织结构演化、腐蚀行为、骨形成能力和细胞粘附行为。 微弧氧化镁表面沉积的钙磷相为二水合磷酸氢钙(DCPD)。 电沉积过程中 DCPD 优先在微弧氧化层的通孔和放电通道处形核、随后长大并覆盖微弧氧化层而起到封孔作用。 涂覆后镁的低频阻抗模值在浸泡初期超过了 10⁵ Ω·cm² ,且在 120 h 内基本保持稳定;腐蚀电流密度与纯镁相比下降了约 3 个数量级,复合涂层显著地提高了镁的耐蚀性。 复合涂层在模拟体液和细胞培养液中均表现出了诱导羟基磷灰石(HA)沉积的能力,在细胞培养液中浸泡 14 d 后涂层表面出现球状类骨 HA 组织;细胞黏附试验中,活细胞几乎黏附在整个涂层表面,表现出良好的骨形成能力和细胞活性。     

电流密度对电结晶羟基磷灰石生物涂层性能的影响

改变电流密度在钛合金表面电结晶出磷酸钙预涂层,经碱液处理转变为羟基磷灰石（ｈｙｄｒｏｘｙａｐａｔｉｔｅ,ＨＡ）。扫描电镜（ＳＥＭ）,Ｘ射线衍射（ＸＲＤ）分析及拉伸实验与模拟体液实验表明：小电流密度预涂层为致密片状ＣａＨＰＯ４－２Ｈ２Ｏ,随电流密度增加涂层为疏松、细针状Ｃａ３（ＰＯ４）２－ｎＨ２Ｏ,但经过碱液处理都转变为羟基磷灰石;羟基磷灰石涂层的拉伸强度随电流密度增加而降低,在模拟体液中的溶解较弱     

水热时间对钛合金微弧氧化膜合成羟基磷灰石的影响

目的研究水热时间对TC4钛合金微弧氧化膜合成羟基磷灰石(HA)的影响。方法对TC4钛合金微弧氧化膜进行不同时间的水热合成处理,分析其微观形貌、成分及相结构,观察其在模拟体液中浸泡5周后的形貌及结构变化。结果水热处理提高了微弧氧化膜的Ca/P摩尔比,使非晶态钙磷化合物转化为HA晶体,随着水热时间的延长,HA衍射峰数量增多且强度增加。在模拟体液中浸泡5周后,微弧氧化膜表面仅有微量磷酸钙形成,而如水热合成后再浸泡,氧化膜表面的HA几乎完全转化为磷酸钙。结论水热处理有助于钛合金微弧氧化膜表面合成HA晶体。在8 h内,水热时间越长,氧化膜表面的HA含量越高,模拟体液中浸泡后形成的磷酸钙也越多,与人体的相容性越好。     

钛基材上电化学沉积羟基磷灰石

通过电沉积法在经过阳极氧化的钛基材表面沉积磷酸钙盐涂层,再经碱热处理使磷酸钙涂层转变为羟基磷灰石涂层。扫描电镜(SEM)观察了阳极氧化后生成的TiO2纳米管的微观结构,以及生成的羟基磷灰石的形貌。X射线衍射仪(XRD)分析了涂层的相组成,同时测定了涂层与基体的结合强度。试验结果表明:电沉积涂层CaHPO4·2H2O经碱处理后转变为羟基磷灰石;电沉积添加双氧水与钛基材经过阳极氧化后使得涂层与基体结合强度有所提高。模拟体液浸泡试验表明涂层具有良好的生物活性。     

医用镁合金丝材的微弧氧化表面改性(英文)

在硅酸盐-磷酸盐复合电解质中添加羟基磷灰石纳米粉体和氢氧化钠进行改性处理,然后采用该电解质对医用镁合金丝材进行微弧氧化处理。研究电解质中氢氧化钠含量对镁合金丝材表面陶瓷涂层微观组织结构和性能的影响。结果表明:对电解质改性后,镁合金丝材的微弧氧化起弧电压大降低且氧化速度更快。镁合金丝材在添加2 g/L氢氧化钠的电解质中进行微弧氧化处理后的耐腐蚀性能改善幅度显著。在模拟体液的早期浸泡过程中,微弧氧化处理过的镁合金丝材表现为缓慢且稳定的腐蚀降解。在浸泡28 d后,镁合金丝材表面的保护性陶瓷涂层尚未破坏,但浸泡60 d后,镁合金丝材出现了显著的腐蚀降解。     

Improvement of anticorrosion and adhesion to magnesium alloy by phosphate coating formed at room temperature

A new surface protection process was developed to magnesium alloy against corrosion in aggressive environments. Firstly, a phosphate coating was formed on rinsed magnesium alloy. Then, powder painting was carried out on the phosphated magnesium alloy. Surface morphologies and phase compositions of the phosphate coating were investigated by X-ray diffraction （XRD） and scanning electron microscope （SEM）. The results show that the phosphate coatings formed in bath containing earth additives at room temperature have dense and fine microstructure. The phosphate coating provides excellent paint adhesion to the magnesium alloy. Salt spray tests indicate that the corrosion resistance of the phosphate coating plus paint could meet the demand of magnesium alloy automobile components in aggressive environments.     

Effect of Heat Treatments on HVOF Hydroxyapatite Coatings

Highly crystalline hydroxyapatite (HAp) powder was thermally sprayed onto Ti-6Al-4V substrates using the High-Velocity Oxy-Fuel (HVOF) process. Coatings were heat treated for 60 min at 700 °C to study the influence of the crystallization on chemical and mechanical properties. Characterization of the HAp coatings was carried out by Fourier Transform Infrared Spectroscopy (FTIR) and x-ray diffraction (XRD) using Rietveld analysis. The results showed that the coatings were highly crystalline (82%) and no other phases of calcium phosphate were present. Coatings were 100% crystalline after the heat treatment. Bioactivity of the coatings was investigated by immersion in Kokubo’s simulated body fluid. The dissolution/precipitation behavior was studied and the degradation of HAp coatings caused by the immersion test was studied by measuring the adhesion strength of the coatings. After immersion in SBF bond strength decreased for the as-sprayed coatings, without any thermal treatment, but it was constant for the heat-treated coatings. This phenomenon was related to the dissolution of the amorphous phase in the interface substrate-coating in the as-sprayed coatings.     

脉冲电化学沉积羟基磷灰石涂层改善Mg-Nd-Zn-Zr合金在模拟体液中的耐腐蚀性能

采用脉冲电化学沉积的方法,在新开发的Mg-Nd-Zn-Zr合金(JDBM)表面制备出了羟基磷灰石(HA)涂层,并对其耐蚀性能和血液相容性进行了研究.结果表明,表面改性后的JDBM镁合金具有更好的耐腐蚀性能,腐蚀后涂层保持了良好的完整性,析氢试验也表明涂层对基体在仿生腐蚀环境中有一定的保护作用,且不会引起模拟体液pH值较...     

Plasma-Sprayed Hydroxyapatite Coating for Improved Corrosion Resistance and Bioactivity of Magnesium Alloy

In the present study, the corrosion resistance and bioactivity of AZ91HP magnesium alloy were improved by plasma spraying hydroxyapatite (HA) coating. X-ray diffraction measurements indicated that the coating formed amorphous and little β-Ca₃ (PO₄)₂ besides of HA. The corrosion resistance and bioactivity of the coating and magnesium alloy in simulated body fluid were investigated using immersion test. The coating showed lower corrosion rate and better bioactivity than magnesium alloy. The coating significantly improved the hydrophilicity of Mg alloy. The prothrombin time of the coating was 18 s, and the prothrombin time of Mg alloy was 11 s, so the coating had better anticoagulant activity.     

Durability of Titanium/Dicalcium Silicate Composite Coatings in Simulated Body Fluid

Titanium/dicalcium silicate composite coatings with different ratios (weight ratios as Ca₂SiO₄: Ti = 3:7, 5:5, 7:3) were prepared by plasma spraying. Effects of titanium addition on coating properties, such as bonding strength, flexural modulus, and dissolution in simulated physiological environment, were studied. Results showed that the bonding strength between coating and Ti-6Al-4V substrate increased with increase of titanium content in the composite coatings. It was explained by the narrowed dissimilarity of thermal expansion coefficients between the coatings and substrates. Degradation of mechanical properties after immersion in simulated body fluid was also studied. The dissolution of dicalcium silicate in the composite coatings resulted in the decrease of flexural strength and flexural modulus of the coatings in the simulated physiological environment. The higher titanium content in the composite coatings, the stabler are the composite coatings in the physiological environment.     

等离子喷涂人工骨涂层材料

等离子喷涂是一种常用的生物医用材料表面改性技术,被广泛应用于钛等金属人工骨的表面改性.为了满足人工骨涂层的临床应用需要,近年来发展了一些新的涂层材料和后处理工艺技术.利用火焰蒸汽处理技术对等离子喷涂羟基磷灰石涂层进行后处理,提高了涂层的结晶度,降低其在体液中的降解.经碱处理的等离子喷涂钛涂层,生物活性有了明显的改善.等离子喷涂硅灰石和硅酸二钙陶瓷是一类不同于传统磷酸钙系的新型生物活性材料,其性能和结构已被初步研究.同时介绍了等离子喷涂人工骨涂层材料在这几个方面的近期研究进展.     

Protection behaviour of surface films formed on AZ91D magnesium alloy in nitrogen/1,1,1,2-tetrafluoroethane atmospheres

Protective surface coatings on an AZ91D magnesium alloy were formed in an atmosphere mixture of nitrogen and 1,1,1,2-tetrafluoroethane (HFC-134a). The surface composition and microstructure were characterized using X-ray diffraction analysis and scanning electron microscopy, respectively. The cross-section morphologies of the coatings show that an increase in conversion time results in an increase in the continuity and compactness of the coating generated on the surface of the AZ91D alloy. The corrosion resistance tests performed by immersion into 3.5% NaCl solutions were investigated by electrochemical measurements. The results showed that the coated samples had higher corrosion resistance than the uncoated alloy. On the other hand, the corrosion density of the coated samples decreased by increasing the conversion time by about two orders of magnitude, compared with the un-coated samples. This behaviour is attributed to the formation of a protective surface film constituted mainly for MgF2, together with other phases. The nature of these phases depends on the process conditions.