微束等离子喷涂羟基磷灰石涂层相结构的微拉曼光谱研究

羟基磷灰石(Hydroxyapatite,HA)涂层以其优异的生物相容性和骨传导性在生物医疗领域得到了广泛应用。然而,HA涂层的生物性能与其组织结构密切相关。本研究采用微束等离子喷涂技术,在Ti-6Al-4V基体上制备HA扁平粒子及HA涂层。采用扫描电镜(SEM)分别对原始HA粉末、HA扁平粒子表面和HA涂层截面的形貌进行了观察。通过微拉曼光谱对扁平粒子和涂层截面微区的相结构进行分析,得到磷酸基团(PO_4~(3-))及羟基基团(OH~-)在所选定区域的信息,对900～1 000 cm~(-1)频率范围的内的微拉曼光谱进行分峰拟合,获得了微束等离子喷涂HA扁平粒子表面相分布情况以及HA涂层沿厚度方向相结构的变化。结果表明,单个HA扁平粒子以非晶相为主,而在涂层中,靠近基体部分的相组成以非晶相及分解相(β-TCP)为主,仅包含少量HA晶体相,随着离涂层与基体界面距离的增加,非晶相及分解相含量逐渐减少,HA相增多,在近涂层表面非晶相和分解相(β-TCP)略有增加。     

SiC/Ti-6Al-4V复合材料界面反应的扫描电镜分析

采用扫描电镜分析了国产SiC纤维增强Ti-6Al-4V复合材料的界面反应,发现不带C涂层的SiC纤维与Ti-6Al-4V反应形成TiC和钛的硅化物,带有C涂层的SiC纤维与Ti-6Al-4V反应仅形成TiC.观察表明C涂层的厚度差别较大.     

微波烧结法制备羟基磷灰石/TiO_2复合涂层

钛合金作为骨植入材料具有耐腐蚀和良好的力学性能,但是没有生物活性。以医用钛合金Ti-6Al-4V为基体,利用微波烧结在钛合金基体表面成功制备出羟基磷灰石/二氧化钛(HA/TiO_2)复合涂层。利用扫描电镜(SEM)、X射线衍射仪(XRD)、模拟体液(SBF)对涂层表面形貌、成分、活性进行了分析。结果表明,由HA和TiO_2组成的涂层在基体表面分布均匀,并可以在基体表面观察到针状、片状的HA。SBF实验结果观察到,HA在经过涂层的钛合金基体表层持续沉积,形成了更加均匀的片层、针状表层结构,而相比之下没有涂层的钛合金表面仅仅形成了容易脱落的块状表层结构。实验结果说明,表面复合涂层的存在提高了材料表面的生物活性,为骨细胞的进一步粘附生长提供了较好的生存空间。     

用溶胶凝胶法在碱处理TC4合金表面制备羟基磷灰石涂层

为提高羟基磷灰石(HA)涂层与Ti基体的结合强度,科研人员探索了多种涂层技术,如等离子喷涂、电泳沉积、激光熔覆等.然而,这些方法都存在一定缺陷,例如高温会影响基体的性能,形成意外相,涂层不均匀及产生热应力等.溶胶凝胶制备法是一种低温下合成材料的工艺,具有可形成均匀的微观结构、生成材料比表面积较大、残余羟基较多等优点,因而该方法在制备HA涂层方面备受关注.本研究从结合性能人手,研究了TC4合金(Ti-6A1-4V)经碱处理后的HA涂层制备工艺及其与基体的结合强度.     

C涂层对SiC纤维增强Ti基复合材料界面的影响

采用透射电镜和扫描电镜研究了SiC纤维增强Ti基复合材料的界面反应,重点分析了C涂层对界面行为的影响.结果表明,C涂层可以明显改善纤维和基体之间的界面结合状况;SiC/C/Ti-6Al-4V复合材料的界面反应产物是主要为TiC,而无C涂层SiC/Ti-6Al-4V的界面反应产物为TiC,Ti5Si3和Ti3SiC2界面反应层生长受扩散控制,其厚度增长满足抛物线生长规律,SiC/C/Ti-6Al-4V由于C涂层消耗完毕前后的不同情况,其界面反应层生长并不完全符合这一规律,C涂层的存在可以有效的抑制界面反应的进行.     

Ti-6Al-4V合金表面微弧氧化涂层的制取及其耐磨性能

研究了Ti-6Al-4V合金的阳极氧化处理工艺,在合金表面获得了耐磨性能优异的微弧氧化(MAO)涂层.     

微束等离子喷涂羟基磷灰石涂层

采用微柬等离子喷涂（MPS）在Ti6A14V基体上制备了羟基磷灰石（HA）涂层，并以大气等离子喷涂（APS）为对照．利用光学显微镜、SEM和XRD分析技术对MPS涂层形貌、相组成和结晶度进行了研究．结果表明：在微柬等离子喷涂过程中，HA的分解程度比大气等离子喷涂有显著降低，除了HA相，仅形成β-TCP相和非晶相．MPS涂层的结晶度主要受喷涂距离的影响．喷涂距离较短（〈80mm）时，涂层结晶度高于APS方法制备的涂层．喷涂距离在130mm时，涂层结晶度低．大气等离子喷涂层含有β-TCP、α-TCP、TTCP、CaO和非晶．MPS涂层分解较APS少的主要原因是喷涂过程中HA粒子过热不严重．     

喷涂工艺参数对HA涂层结构和结晶度的影响

用微束等离子喷涂在TiAl6V4基体上制备羟基磷灰石涂层,研究了喷涂电流、喷涂距离和气流量等参数对其显微结构和结晶度的影响.结果表明,通过调整喷涂工艺参数可获得三类不同结构的涂层.第一类结构含有大量未融化HA颗粒,第二类结构呈典型层状且具有强织构,第三类结构层状结构不明显.前两种结构的结晶度较高,第三类结构的结晶度较低.由二和三类结构复合而成的梯度涂层,能够适应植入体涂层快速形成类骨磷灰石和保持稳定性的双重要求.     

搪瓷涂层对Ti-24Al-14Nb-3V抗氧化及热腐蚀性能的影响

研究了搪瓷涂层对Ti-24Al-14Nb-3V抗高温氧化及热腐蚀性能的影响.结果表明,在900℃下,由于搪瓷涂层具有较高的化学稳定性,且和Ti-24Al-14Nb-3V有比较接近的热膨胀系数,大大改善了Ti-24Al-14Nb-3V抗恒温氧化及循环氧化性能.在850℃(Na,K)2SO4中,虽然熔盐中的Na+与搪瓷涂层中的Ca2+进行离子交换引起搪瓷涂层少量减重,但它仍具有优异的抗熔融硫酸盐腐蚀能力.在850℃NaCl+Na2SO4中,搪瓷涂层对Ti-24Al-14Nb-3V具有一定的保护作用,但是由于熔盐中的Na+与搪瓷涂层中的Ca2+进行离子交换,和熔盐中的Cl-对搪瓷涂层的腐蚀作用及对基材的点蚀作用,使其保护作用下降.     

等离子喷涂/水热合成HA涂层的制备和模拟体液及体内实验

等离子喷涂磷酸氢钙涂层经过水热处理转化为羟基磷灰石 (HA)涂层 ,该涂层由高纯度的缺钙HA组成 ,结晶性高。水热合成HA涂层在模拟体液中的溶解性和结合强度衰减均低于等离子喷涂HA涂层 ,体内实验表明水热合成HA涂层的生物学性能良好     

等离子喷涂HA/Ti复合涂层研究 I.结构、组成和力学性能

采用等离子喷涂方法,在Ｔｉ－６Ａｌ－４Ｖ基体上成功地制备了ＨＡ／Ｔｉ复合涂层,并对复合涂层的微观结构,相组成和力学性能进行了研究。结果表明,ＨＡ和Ｔｉ两相均匀地分布于复合涂层中。ＨＡ／Ｔｉ复合涂层的结合强度明显高于纯ＨＡ涂层,这主要是由于ＨＡ／Ｔｉ的复合和了涂层与基体之间的热膨胀系数失配,ＨＡ／Ｔｉ复合涂层在模拟体液中浸泡一段时间后,结合强度没有明显降低,ＨＡ／Ｔｉ复合涂层的断裂韧性和硬度均高于Ｈ     

等离子喷涂HA/Ti复合涂层研究 I.结构、组成和力学性能

采用等离子喷涂方法,在Ｔｉ－６Ａｌ－４Ｖ基体上成功地制备了ＨＡ／Ｔｉ复合涂层,并对复合涂层的微观结构、相组成和力学性能进行了研究．结果表明,ＨＡ和Ｔｉ两相均匀地分布于复合涂层中．ＨＡ／Ｔｉ复合涂层的结合强度明显高于纯 ＨＡ涂层,这主要是由于 ＨＡ／Ｔｉ的复合缓和了涂层与基体之间的热膨胀系数失配．ＨＡ／Ｔｉ复合涂层在模拟体液中浸泡一段时间后,结合强度没有明显降低．ＨＡ／Ｔｉ复合涂层的断裂韧性和硬度均高于 ＨＡ涂层．     

等离子喷涂制备 HA/ZrO2复合涂层

采用等离子喷涂技术,在Ｔｉ－６Ａｌ－４Ｖ基体上成功地制备了羟基磷灰石／氧化锆（ＨＡ／ＺｒＯ２）复合涂层,对涂层的微观结构、相组成和结合强度进行了研究,并以模拟体液试验评估涂层的生物活性．结果表明,复合涂层具有较为均匀的微观结构．ＨＡ／ＺｒＯ２复合涂层的结合强度明显高于 ＨＡ涂层, ＨＡ／６０ ｗｔ％ ＺｒＯ２涂层的结合强度高达 ２８．５ＭＰａ,为 ＨＡ涂层的 ２．２倍．复合涂层在模拟体液中浸泡一段时间后,表面覆盖一层碳酸磷灰石（ｃａｒｂｏｎａｔｅ－ａｐａｔｉｔｅ）,表明涂层具有良好的生物活性．     

The cell attachment and morphology of neonatal rat calvarial osteoblasts on the surface of Ti-6Al-4V and plasma-sprayed HA coating: Effect of surface roughness and serum contents

The biocompatibility of material plays an important role in the bone–implant interface for the prosthetic implant fixation. The biocompatibility of implants is associated with the chemical composition, surface topography, surface energy and surface roughness of biomaterials. The effects of two factors, surface roughness and serum contents, on osteoblast behavior at the surface of Ti-6Al-4V and plasma sprayed HA coating were investigated in the experiment. The osteoblasts derived from neonatal rat calvarial were cultured in Dulbeccos modified Eagle medium (DMEM) with fetal bovine serum (FBS) on the surface of polished Ti-6Al-4V (Ti-p), grit-blasted Ti-6Al-4V (Ti-b), polished HA coating (HAC-p), and as-sprayed HA coating (HAC). Under culture medium containing 4% FBS, the level of cell attachment to the polished surface is significantly higher than the rough surface of the same experimental materials during all culture periods. Increasing the contents of FBS up to 10%, the difference of osteoblast attachment is not found between Ti-p and Ti-b. Under 4% serum condition, the cell morphology attached to smooth surfaces (Ti-p and HAC-p) is spread faster and are more flattened than the one to rough surface of the same experimental materials by SEM. After 24 h culture, the corroded cracks are easily observed at the surface of polished HA coatings, and the cell morphology on HAC-p coatings are elongated and less flattened compared with Ti-p. The result is consistent with statistical difference of cell attachment between Ti-p and HAC-p under 4% serum condition.     

Plasma sprayed hydroxy apatite coatings

This paper describes the method of producing plasma sprayed coatings of hydroxy apatite (HA) on metallic substrates of Ti-6Al-4V. Hydroxy apatite is a material which has similar composition to that of the mineral phase of the human bone. Poor mechanical properties however inhibits its use in the load bearing applications. The powders prepared in our laboratory are sprayed using a plasma spray torch operating in ambient. The deposited coatings are charaterized by X-ray diffraction and found to retain HA in the coatings as per requirements. Paper presented at the poster session of MRSI AGM VI, Kharagpur, 1995.     

等离子喷涂制备HA/ZrO2复合涂层

采用等离子喷涂技术,在Ｔｉ－６Ａｌ－４Ｖ基体上成功地制备了羟基磷灰石／氧化锆（ＨＡ／ＺｒＯ２）复合涂层,对涂层的微观结构,相组成和结合强度进行了研究,并以模拟体液试验评估涂层的生物活性,结果表明,复合涂层较有较为微观结构,ＨＡ／ＺｒＯ２复合涂层的结合强度明显高于ＨＡ涂层,ＨＡ／６０ｗｔ％ＺｒＯ２涂层的结合强度高达２８．５ＭＰａ,为ＨＡ涂层的２．２倍,复合涂层在模拟体液中浸泡一段时间后,表面覆盖一层     

Evaluation of the efficiency of TiB2 and TiC as protective coatings for SiC monofilament in titanium-based composites

The vigorous interfacial reactions in SiC/Ti-6Al-4V composites at elevated temperatures lead to the deterioration of the mechanical properties of the composites. TiB₂ and TiC were selected as potential protective coatings for SiC fibres in titanium-based composites. These coatings were deposited on to fibres by the chemical vapour deposition technique. Comparisons and evaluations have been made of the effectiveness of these ceramics as protective coatings for SiC fibres by incorporating the coated fibres into a Ti-6Al-4V matrix using the diffusion bonding method. Emphasis has been placed on the chemical compatibility of the candidate coating with SiC and Ti-6Al-4V by examining the interfaces of the fibre/coating/matrix using microscopic methods and chemical analysis. A stoichiometric TiB₂ coating was found to be stable with SiC and has proved an effective barrier to prevent the SiC fibre from reacting with the Ti-6Al-4V. The TiC coating showed no apparent reaction with a titanium-alloy matrix under the conditions studied, but was found to react with the SiC fibre substrate.     

Characterization and tribological evaluation of duplex treatment by depositing carbon nitride films on plasma nitrided Ti-6Al-4V

Carbon nitride (CN_X) films (with N/C ratio of 0.5) were deposited on both untreated and plasma nitrided Ti-6Al-4V substrates by D.C. magnetron sputtering using a graphite target in nitrogen plasma. TEM and XPS analysis revealed the formation of both amorphous CN_X structure and crystalline -C₃N₄ phases in the deposited coatings. Nano-indentation tests showed that the film hardness was about 18.36 GPa. Both the scratch tests and indentation tests showed that compared with CN_X film deposited directly on Ti-6Al-4V, the load bearing capacity of CN_X film deposited on plasma nitrided Ti-6Al-4V was improved dramatically. Ball-on-disk wear tests under both dry sliding and lubricated conditions (with simulated body fluids) were performed to evaluate the friction and wear characteristics of the deposited coatings. Results showed that under both dry and lubricated conditions, the duplex treated system (i.e., with CN_X film deposited on plasma nitrided Ti-6Al-4V substrate) was more effective in maintaining a favorable low and stable coefficient of friction and improving wear resistance than both individual plasma nitriding and CN_X films on Ti-6Al-4V substrate. Under dry sliding conditions, the generated wear debris of spalled films were accumulated on the wear track, mechanically alloyed and graphitized, thus significantly reducing the coefficient of friction and preventing wear of the substrate. However, under lubricated conditions, due to the flowing of the fluids, the lubricating wear debris was taken away by the fluids, and therefore, the direct contact of two original surfaces resulted in high coefficient of friction and extensive abrasive wear of the substrate for CN_X films deposited on Ti-6Al-4V substrate. Also when there was some small-area spallation of CN_X films, the fluids could seep into the interface between the film and substrate, thus degrading the interfacial adhesion and resulting in a large area spallation.     

Untersuchungen zur Eignung von ionenplattierten metallischen Schutzschichten auf Ti-6Al-4V bei Schwingungsverschleißbeanspruchung

Investigations on the Suitability of lon-Plated Metallic Coatings on Ti-6Al-4V at Fretting Fatigue Load To provide fretting fatigue damage flat specimens of the alloy Ti-6Al-4V were supplied with metallic coatings. For that purpose specimens were coated with Cu, Cr, V, Ti and with an Al/Cu-combination. These coated specimens were then tested in a fretting bridge equipment. It was found that all coatings except the Al/Cu-combination lead to considerable improvement of fretting fatigue life. As SEM-investigations show, a separation of the functions of specimen-body and specimen-surface was achieved by the coatings, so that the effectiveness of coatings of rather low wear-resistance is explicable.     

Laser engineered multilayer coating of biphasic calcium phosphate/titanium nanocomposite on metal substrates

In this work, laser coating of biphasic calcium phosphate/titanium (BCP/Ti) nanocomposite on Ti-6Al-4 V substrates was developed. A continuous wave neodymium-doped yttrium aluminium garnet (Nd:YAG) laser was used to form a robust multilayer of BCP/Ti nanocomposite starting from hydroxyapatite and titanium nanoparticles. In this process, low power coating is realized because of the strong laser-nanoparticle interaction and good sinterability of nanosized titanium. To guide the optimization of laser processing conditions for the coating process, a multiphysics model coupling electromagnetic module with heat transfer module was developed. This model was validated by laser coating experiments. Important features of the coated samples, including microstructures, chemical compositions, and interfacial bonding strength, were characterized. We found that a multilayer of BCP, consisting of 72% hydroxyapatite (HA) and 28% beta-tricalcium phosphate (β-TCP), and titanium nanocomposite was formed on Ti-6Al-4 V substrates. Significantly, the coating/substrate interfacial bonding strength was found to be two times higher than that of the commercial plasma sprayed coatings. Preliminary cell culture studies showed that the resultant BCP/Ti nanocomposite coating supported the adhesion and proliferation of osteoblast-like UMR-106 cells.