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激光熔覆生物陶瓷涂层温度场的数值模拟 总被引:11,自引:0,他引:11
本文针对激光熔覆原位合成生物陶瓷涂层的试验过程,进行了相应的数值模拟。计算出激光熔覆合成羟基磷灰石等钙磷基生物陶瓷的三维温度场。结果表明激光熔覆形成的温度场有利于生物陶瓷涂层形成细小且呈梯度分布的组织。 相似文献
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钛合金表面三种预涂材料的激光熔覆研究 总被引:2,自引:0,他引:2
为提高钛合金的表面耐磨性能,分别以NiCrBSi、NiCrBSi B4C和B4C Ti三种材料体系为预涂粉,在Ti-6Al-4V表面涂覆不同厚度的预涂层,采用CO2激光器进行激光熔覆工艺研究.在相同激光熔覆工艺条件下,对不同材料体系的涂层质量进行观察与分析,确认NiCrBSi B4C材料涂层是三种材料体系中最好的.在激光熔覆过程中,NiCrBSi B4C材料中的B4C和Ti发生反应,原位生成增强相,对涂层有强化作用.而且,NiCrBSi的加入控制了原位反应的剧烈程度,减少裂纹和气孔,保证了涂层质量. 相似文献
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在分析金属间化合物涂层材料特点的基础上,综述各种激光熔覆合成金属间化合物涂层的研究现状,分析各种金属间化合物涂层的组织及性能,研究表明激光熔覆合成的金属间化合物涂层均具有优异的耐磨、耐腐蚀、抗氧化等性能。 相似文献
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以BN和Ni60A合金粉末作为预置涂层,采用氩弧热源在Ti6Al4V合金表面原位合成陶瓷颗粒复合涂层。经过热力学计算和扫描电子显微镜线扫描分析,利用X射线衍射仪进行涂层物相分析,确定陶瓷颗粒为TiB2和TiN。利用扫描电子显微镜观察微观组织形貌,并探讨TiB2-TiN颗粒的形成机理。实验结果表明,采用适宜的熔覆材料合金粉末成分和熔覆工艺参数,可以获得TiB2-TiN颗粒复合涂层,TiB2形态呈棒状和细条状,TiN形态呈颗粒状。颗粒尺寸细小,分布均匀,且与基体冶金结合。复合涂层的显微组织沿层深方向分为熔覆区、结合区和热影响区。 相似文献
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为了探究激光熔覆对高速车轮钢合金涂层摩擦与磨损性能的影响,利用LDM2500-60型半导体全固态激光器在高速车轮钢表面激光熔覆制备Fe基合金涂层。分别采用金相显微镜、能量色散X射线光谱仪、X射线衍射仪(XRD)分析了熔覆涂层的组织结构、元素分布以及物相,利用MM-2000高速摩擦试验机研究了高速车轮材料激光熔覆处理前后轮轨材料的摩擦磨损性能。结果表明:激光熔覆处理能有效改善车轮材料的抗磨损性能,熔覆涂层主要由γ-Fe、Cr7C3碳化物以及含铁固溶体等物相组成,涂层组织主要以树枝晶和共晶为主;车轮合金涂层的磨损速率相比基体材料降低了51%左右,车轮熔覆铁基合金后的轮轨磨损机制主要表现为轻微的磨粒磨损和氧化磨损。 相似文献
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硅钢表面激光熔覆高硅涂层对性能的影响 总被引:2,自引:0,他引:2
用Nd:YAG脉冲激光在低硅钢表面制备激光熔覆高硅涂层,研究了激光熔覆高硅涂层样品的组织和磁性能.结果表明,制备出的激光熔覆高硅涂层组织致密、无气孔和裂纹,且与基体有良好的冶金结合.经激光熔覆后硅钢表面存在熔覆区、界面结合区和热影响区.熔覆区的显微组织不均匀,随着与结合界面距离的增加,由柱状晶变为树枝晶,最终过渡到表层的细小树枝晶组织.熔覆层与基体之间的结合界面为平面晶组织,热影响区为马氏体组织.熔覆涂层的显微硬度远高于低硅钢基体,其主要原因是涂层具有较高的Si含量,涂层中的α-Fe和γ-Fe双相组织也导致了硬度的提高.激光熔覆高硅涂层硅钢样品经扩散退火后具有室温铁磁性,Si含量的提高使其室温直流磁性能优于原始低硅钢. 相似文献
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激光熔覆生物陶瓷涂层生物相容性的研究 总被引:7,自引:0,他引:7
TC4基激光熔覆生物陶瓷涂层组织细小,且具有一定程度择优取向,涂层与基体间为化学冶金结合等特征。这些特征对骨组织的生物结合及稳定提供了有利条件,故植入活体后该涂层表现出良好的生物相容性及成骨性能。 相似文献
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为了研究激光器对Ni基碳化钨合金熔覆层组织结构和性能的影响,分别采用Nd:YAG与CO2激光熔覆技术在NAK80模具钢表面制备了Ni基碳化钨合金层,利用X射线衍射仪(XRD)、扫描电镜(SEM)、能谱仪、显微硬度计以及摩擦磨损试验机测试分析了2种熔覆层的组织结构、显微硬度及耐磨性能。结果表明:2种熔覆层与基体之间均呈现良好的化学冶金结合;熔覆层组织主要为粗大的未熔碳化钨颗粒和均匀分布的树枝晶,Nd:YAG激光熔覆层的组织比CO2激光熔覆层的细小;2种熔覆层相结构主要包括WC,W2C,Cr23C6,NiCr,CrB2以及γ-Ni等;2种激光器熔覆处理后,NAK80模具钢表面硬度和耐磨性都得到显著改善,CO2激光熔覆层的硬度和耐磨性高于Nd:YAG激光熔覆层,2种激光熔覆试样的磨损机制均为磨粒磨损。 相似文献
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激光熔覆技术采用高能量密度的激光作为工艺的能量来源,能够对工件表面进行改性和修复,显著地改善了基体的表面力学性能,从而有效地延长了产品的生命周期。激光熔覆是制备高熵合金的典型工艺之一,采用该技术并且添加合适的合金元素可以制备具备卓越性能的高熵合金涂层。为清晰地阐明加入元素后增强激光熔覆高熵合金涂层硬度的作用机制,首先综述了目前国内外在激光熔覆过程中加入常见元素所制备的高熵合金涂层硬度性能的研究现状,其中高熵合金有特殊的“4种效应”,对金属间化合物有促进作用,其内部微观结构一般为FCC、BCC或者HCP等固溶相,通常通过固溶强化、沉淀强化和分散强化来强化,并且激光熔覆法会使高熵合金涂层快速冷却,从而显著改善合金的力学性能。其次,分析了金属与非金属两大类元素对激光熔覆制备高熵合金涂层硬度强化的机理,总结了金属元素与非金属元素的添加对高熵合金涂层硬度的影响规律。最后,针对激光熔覆制备高熵合金涂层硬度性能的改进,总结出了有效的方法,并对其未来发展进行了展望。研究结果揭示了激光熔覆高熵合金涂层硬度强化的理论基础,为该领域的进一步发展提供了理论依据。 相似文献
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Hu Mulin Pan Lin Fu Yongqing Xie Changsheng Wang Aihua 《材料保护》2005,38(11):1-5
0 IntroductionMetal matrix composites(MMCs)can usuallyprovide a high stiffness to weight ratio and high wearresistance,and a material with a surface MMC hasthe potential to develop these properties on its sur-face[1].And laser cladding has been found to be anefficient technique to prepare MMC coatings on thesubstrates such as Al-based alloy,steel,brass andbronze[2~4].Among various MMC coatings preparedby laser cladding,those reinforced with oxides(mainly Al2O3)and carbides(TiC,SiC,B4C,… 相似文献
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以FeCoCrMoCBY块体合金为熔覆材料,采用激光熔覆在低碳钢表面制备非晶涂层,探讨不同激光功率对涂层成形及组织的影响,通过显微硬度仪、电化学工作站测试涂层显微硬度及耐腐蚀性能。研究结果表明,其他参数不变,激光功率为17.6~20.8 W时,涂层成形良好,与基材呈典型冶金结合。随激光功率增加,涂层稀释率升高,裂纹倾向增大,非晶化程度降低。激光功率为17.6 W时,涂层主要由非晶组成,稀释率低于24.2%,结构致密,包括热影响区、熔合区和熔覆区;涂层平均显微硬度为1 330HV,约高于基材9倍,在3.5%NaCl溶液中的耐腐蚀性能明显优于316L不锈钢。 相似文献
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In this work, the possibility of incorporating proteins into calcium phosphate (Ca-P) coatings, prepared on the surface of starch polymeric biomaterials by means of a biomimetic route, was investigated. The morphology, chemical composition and crystallinity of Ca-P coatings was assessed and related to the incorporation of the studied biomolecules. For that, bovine serum albumin (BSA) and α-amylase were added in concentrations of 1 mg/ml to simulated body fluid (SBF) solutions, being both added at the nucleation or growth stages of the biomimetic coating process. A biodegradable blend of corn starch/ethylene vinyl alcohol (SEVA-C) was used as substrate and bioactive glass (45S5 Bioglass®) was used as the nucleating agent. The obtained Ca-P coatings were characterised by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy using an attenuated reflectance device (FTIR-ATR) and thin-film X-ray diffraction (TF-XRD). Additionally, to evaluate the activity of the incorporated enzyme and the stability of the Ca-P films, coated samples were immersed in an SBF solution for different periods of time. The enzyme activity was measured and the morphology of the coating examined by SEM. The results obtained showed that the presence of protein molecules, at the nucleation or growth stages, lead to the formation of a dense Ca-P film presenting different morphologies that were different of the selected coating conditions. FTIR-ATR analysis detected the presence of carbonate and phosphate groups on the Ca-P layer, indicating the formation of a coating similar to the mineral component of vertebrates bone tissue. When proteins were added, amide I and amide II bands, characteristic groups of protein molecules, were also detected, revealing the efficient incorporation of these biomolecules into the Ca-P coatings.Ca-P coatings, with α-amylase incorporated at the nucleation stage, showed no degradation of the film after incubation in SBF for 28 days. The release of increasing concentration of reducing sugars with degradation time revealed that α-amylase was efficiently incorporated in the coating remaining active throughout the coating preparation. This can be a strategy that will allow, in addition of conferring osteoconductive properties to biodegradable polymers, also simultaneously tailoring their degradation kinetics. 相似文献
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J. E. G. Hulshoff K. Van Dijk J. P. C. M. Van Der Waerden W. Kalk J. A. Jansen 《Journal of materials science. Materials in medicine》1996,7(10):603-609
The bone response to different calcium phosphate (Ca-P) coated implants was evaluated in a goat animal model. Two types of plasma spray coatings were applied to a commercially pure titanium (cpTi) tapered, conical screw-design implant (BioComp®); hydroxyapatite (HA-PS) and a dual coating, consisting of FA and HA (FA/HA-PS). In addition an amorphous RF magnetron sputter coating (Ca-P-a) and uncoated implants were investigated. Forty-eight implants were inserted in the maxilla of 12 adult female goats. After implantation periods of 3 and 6 months, the bone implant interface was evaluated histologically and histomorphometrically. After both implantation periods all plasma spray coated implants were maintained. On the other hand three Ca-P-a and two cpTi implants were lost. Histological examination revealed a better bone response to both plasma spray coated implants. Histomorphometrical evaluation confirmed this finding. At 3 and 6 months significantly higher percentages of bone contact (p<0.001, ANOVA) were measured for both plasma spray coated implants than for the cpTi and Ca-P-a implants, while no significant difference (p<0.05) existed between both implantation periods. Degradation of both plasma spray coatings was observed. Supported by the results, it is concluded that, although Ca-P coatings can improve the performance of dental implants, the presence of a Ca-P coating is not the only important factor for bone healing around implants placed in low density trabecular bone. 相似文献