Surface Modification of Ceramic Materials Using Excimer Laser

1' IatroductionThe surface modification of materials by lasertreatment is an attractive technology, which has beenavailable to materials scientists and engineers forabout 30 years. For example, excimer lasers can provide a rapid and efficient means for surface modification of ceramic materials. After excimer laser, irradiation, surface morphology and structure were modified,and surface properties, such as electric conductivity,catalytic activity and bending strength of ceramics,. Iwere improve…     

Surface Modification of a-Fe Metal Particles by Chemical Surface Coating

The structure of a-Fe metal magnetic recording particles coated with silane coupling agents have been studied by TEM, FT-IR, EXAFS, Mossbauer. The results show that a close, uniform, firm and ultra thin layer, which is beneficial to the magnetic and chemical stability, has been formed by the cross-linked chemical bond Si-O-Si. And the organic molecule has chemically bonded to the particle surface, which has greatly affected the surface Fe atom electronic structure. Furthermore, the covalent bond between metal particle surface and organic molecule has obvious effect on the near edge structure of the surface Fe atoms.     

Surface Modification of α-Fe Metal Particles by Chemical Surface Coating

The structure of α-Fe metal magnetic recording particles coated with silane coupling agents have been studied by TEM, FT-IR, EXAFS, Mossbauer. The results show that a close, uniform, firm and ultra thin layer, which is beneficial to the magnetic and chemical stability, has been formed by the cross-linked chemical bond Si-O-Si. And the organic molecule has chemically bonded to the particle surface, which has greatly affected the surface Fe atom electronic structure. Furthermore, the covalent bond between metal particle surface and organic molecule has obvious effect on the near edge structure of the surface Fe atoms.     

PVD Si涂层用于SiC陶瓷的表面改性研究

为了获得高质量的光学表面,采用RF磁控溅射法在RB SiC和SSiC陶瓷表面涂覆一层结构致密的PVD Si涂层.采用XRD、AFM和表面轮廓仪对抛光后的PVDSi涂层进行了表征,并在可见光波长范围内测量了涂层的反射率.结果表明,当RB SiC和SSiC陶瓷表面涂覆PVD Si涂层后,抛光后其表面缺陷明显减少,表面粗糙度的均方根RMS可达埃级,反射率提升幅度明显.并简单分析了反射率提高的主要原因.     

Metal Surface Treatment and Reduction in Pitting Corrosion of 304L Stainless Steel by Excimer Laser

Abstract

The use of excimer lasers to produce thin rapidly quenched melts on metal surfaces is discussed. Results obtained using a XeCl laser on a variety of metal samples are given. The surface refinement and smoothing induced by laser treatment, giving improved resistance to pitting corrosion and higher etch resistance suggest significant potential for this method as a means of ‘micro-engineering’ surfaces.     

激光表面改性对金属材料表面耐蚀性能的影响

综述了金属材料表面激光改性的工艺方法和特点，及其对金属腐蚀行为的影响，提出了金属表面激光改性中存在的问题及相应的改进措施。     

PCVD法对碳化硅陶瓷的表面改性研究

利用等离子辉光放电化学气相沉积技术（ＰＣＶＤ），控制甲烷与磋烷质量流量比、硅烷与氨质量流量比，在碳化硅基体表面分别沉积上无定形碳化硅和氨化硅薄膜，研究其膜的组成、沉积工艺、厚度等对碳化硅陶瓷的强度改性影响．在一定的沉积条件下沉积的碳化硅薄膜可以使基体强度提高２０％达到８５０ＭＰａ，沉积氮化硅薄膜使强度提高３０％达到９００ＭＰａ，改性的效果很明显．     

内燃机用Ti600钛合金表面激光熔覆NiCr/TiAl涂层组织及摩擦磨损性能

为了提高内燃机用Ti600钛合金的综合性能,对其表面进行激光熔覆处理制得NiCr/TiAl涂层,同时测试了该涂层的各成分与组织结构,之后对其处于环境中的耐磨性进行了模拟测试。研究结果表明:涂层中形成了许多等轴晶,枝状组织以及许多细小的组织,引起晶粒明显细化。形成了块状的晶体组织与部分球形晶粒,还生成了一些纳米尺寸的晶粒。涂层的平均截面显微硬度为832 HV,与界面相距50μm的部位发生了硬度快速减小,在界面处的基体达到了比Ti600基体更高硬度。激光熔覆涂层具备比基体更低的磨损率,常温时涂层达到了最大摩擦系数和磨损率;处于真空环境中最低。常温中进行磨损区域生成了许多磨屑并产生了明显犁沟结构。在高温、低温与真空环境中测试得到了相近的磨损表面组织形态,都形成了磨屑、犁沟与粘着剥落坑。     

NdFeB合金表面激光非晶化的改性技术

对NdFeB永磁合金表面非晶镀（涂）覆层的设计原则、成分设计、沉积方法及非晶镀（涂）覆层的形成条件和可行性研究了理论分析及探讨，提出了NdFeB永磁合金表面激光非晶化改性的技术方法。     

超声振动下车用316L钢激光熔覆WC-Ni涂层组织和摩擦性能分析

通过空气将20 kHz超声波引入WC-Ni的激光熔池内,使316L钢表面形成熔覆涂层。通过实验测试的方式分析超声振动引起的涂层组织结构、硬度、元素分布形态等性能的变化。研究结果表明:在超声振动作用下,涂层内形成了大量的小尺寸晶粒,存在许多等轴晶与部分枝晶,整体组织结构较为致密,制得了性能更优的涂层。与316L不锈钢硬度相比,涂层硬度获得了明显提升;在超声振动作用下,涂层硬度增大。施加超声振动后,WC-Ni涂层摩擦系数降低。通过测试发现,施加超声振动前涂层摩擦系数为0.59,经过超声振动处理得到的涂层摩擦系数降低至0.42,发生了明显减小。磨损量测试结果表明可以利用超声振动制备WC-Ni涂层的方式使试件获得更优耐磨性。     

Laser Modification of Plasma Sprayed Alumina Coating

An alumina coating was developed on mildcarbon steel by plasma spraying and then modifiedby laser remelting.Some characteristics of plasmasprayed ceramic coating before and after laserremelting,such as microstructure,wear resistance,heat shock resistance,hot corrosion property andbond strength,have been investigated in this paper.     

铝粉表面包覆改性的研究进展

金属铝粉具有活性高、熔点低以及光泽度好等优良性能,广泛用于耐火材料、颜料、涂料及印刷油墨等行业,但铝粉易与水、氧气等反应致使其优良性能降低或丧失,而铝粉表面包覆改性对提高其在腐蚀性介质中的稳定性具有重要意义。综述了目前各工业领域用铝粉包覆改性的研究进展,并分析了各包覆改性方法对耐火浇注料用铝粉包覆改性的借鉴作用,进而对耐火浇注料用铝粉包覆改性的研究重点进行了展望。     

基于准分子激光微加工的光热微驱动器(英文)

提出了基于光热(PT)微膨胀原理的新型光热微驱动技术.设计了一种能将纵向光热膨胀转化成横向偏转的微驱动器.以AutoCAD设计图为基础,采用KrF准分子激光微加工系统,在单层高密度聚乙烯(HDPE)上加工出长1 500μm、宽250μm、厚40μm的开关式光热微驱动器.从微驱动器的扫描电子显微镜(SEM)图可以看出,微驱动器形状与AutoCAD设计值符合良好.光热微驱动实验采用脉冲频率可调的半导体激光器(4 mW,650 nm)作为驱动源.实验结果表明,在一定的脉冲频率范围(如0～17 Hz)内,光热微驱动器具有良好的静态和动态特性,其横向偏转量最大可达11μm,足以实现微开关功能.这种光热微驱动器可由激光束直接控制,具有原理新颖、结构简洁、体积小、易于加工制作等特点,在微纳米技术领域和微光机电系统(MOEMS)中具有广阔的应用前景.     

镁合金激光表面改性研究进展

综述了激光表面改性（激光表面重熔、激光表面合金化、激光表面熔敷、激光多层熔数）的研究与应用，最后提出了存在的问题和努力的方向。     

激光熔覆陶瓷超微粉表面改性

用陶瓷超微粉作熔覆材料 ,对常规材料进行表面处理 ,可以极大的提高材料的表面性能。介绍了激光熔覆陶瓷粉的工艺过程 ,并对熔覆层的硬度、粗糙度和熔覆与基底之间的结合情况进行了考察。     

Surface Infiltrating Composite of Fe-base Metal and Ceramics

1.IntroductionMetal matrix composites consist of afamily of advanced materials which mayhave attractive properties including highstrength,high specific modulus,lowcoefficient of thermal expansion,good wearresistance,and attractive high temperature     

钛白粉表面锆-硅二元包膜改性研究

以六偏磷酸钠为分散剂,二氧化锆为锆包覆剂,九水硅酸钠为硅包覆剂,采用中和法在金红石型钛白粉表面进行二元包膜,设计9组正交试验探究搅拌速度、反应温度、分散剂用量、陈化时间对金红石型钛白粉包膜后的性能影响。采用沉降实验、Zeta电位测试、扫描电子显微镜、高分辨透射电子显微镜等对包膜前后的金红石型钛白粉进行表征。研究结果表明,包膜后的金红石型钛白粉的分散性有显著提高;锆硅对金红石钛白粉复合包膜的优化工艺：搅拌速度为350 r/min、反应温度为60 ℃、分散剂质量分数为0.1%、陈化时间为80 min。     

碳纳米管的表面改性与羟基磷灰石的包覆

通过TEM、FTIR及XRD等检测手段对原位合成法制备羟基磷灰石/碳纳米管复合材料过程中碳管的表面改性及影响羟基磷灰石包覆的因素进行了系统探讨. 研究表明, 浓酸处理后, 碳纳米管表面产生大量官能团; 阴离子表面活性剂十二烷基磺酸钠(SDS)的加入提高了碳纳米管与水的相容性; 实验中随着(NH₄)₂HPO₄溶液的加入, 羟基磷灰石原位沉积并形成包覆层. 结果发现: 碳纳米管的表面改性、适当的pH值和陈化温度是得到羟基磷灰石连续包覆层的关键因素.     

Excimer Laser Surface Treatment of Sheet Molding Compound for Adhesive Bonding

High-strength adhesive bonding of polymer composites can be achieved by treating surface with an excimer laser. A sheet molding compound (SMC) was used for the laser surface treatment for adhesive bonding. By subjecting the SMC surface to excimer laser source, the epoxy matrix was selectively removed by ablation, where upon the glass fibers stood exposed, without any inherent damage to their surface. The controllability is proved to be admirable by optimizing processing parameters. A significant improvement of the joint strength was found in the excimer laser treatment. The selective ablation of polymer matrix resulted in a maximized surface roughness, and an interlocking effect: of glass fibers at the joints. It is also possible that capillary effect draws the adhesive between the mating surfaces. This investigation shows that a high quality adhesive joint of polymer composites can be obtained from the excimer laser treatment.     

激光表面改性技术及其研究进展

激光表面改性技术是表面工程中的先进技术之一,其在先进制造与再制造领域的应用备受关注。本文概述了激光表面改性技术中的激光相变硬化、激光熔凝硬化、激光冲击硬化、激光合金化、激光熔覆等,介绍了以上几种激光表面改性技术的研究现状,最后对激光表面改性技术的发展与工程应用的前景进行了展望。