霍尔离子源辅助制备碳化硅改性薄膜的初步研究

应用电子枪蒸发硅,霍尔离子源电离甲烷,并辅助沉积的方法在反应烧结碳化硅（Reaction Bonded Silicon Carbide: RB SiC）基底上沉积了碳化硅（SiC:H）改性薄膜。XRD测试表明制备的碳化硅改性薄膜为α相。通过控制沉积速率,制备了硬度从9.781 GPa-13.087 GPa,弹性模量89.344 GPa-123.413 GPa的碳化硅改性薄膜。比较同样条件下都镀制银膜的抛光良好微晶玻璃和经过精细抛光的改性反应烧结碳化硅,两者有相近的反射率。附着力实验表明制备的薄膜和基底有良好的结合。在温度冲击实验下,制备的薄膜无龟裂和脱落。     

离子辅助制备碳化硅改性薄膜

介绍了一种利用霍尔型离子源辅助电子束蒸发,在反应烧结碳化硅(RB-SiC)材料上制备硅改性薄膜的方法,研究了不同沉积速率下薄膜改性后的抛光效果.对样品进行了表面散射及反射的测量.通过样品的显微照片可知,硅膜层在沉积速率增大的条件下结构趋于疏松.在精细抛光镀制有硅改性薄膜的反应烧结碳化硅样品后,表面散射系数减小到1.46%,反射率接近抛光良好的微晶玻璃.温度冲击实验和表面拉力实验表明:硅膜无龟裂和脱落,性质稳定,与碳化硅基底结合良好.     

反应烧结碳化硅表面改性的初步研究

应用电子束蒸发硅,霍尔离子源电离甲烷,并辅助沉积的方法在反应烧结碳化硅(RB SiC)基底上沉积了碳化硅(SiC:H)改性薄膜.X射线衍射(XRD)测试表明制备的碳化硅改性薄膜为α相.通过控制沉积速率,制备了硬度为9.781～13.087GPa,弹性模量为89.344～123.413GPa的碳化硅改件薄膜.比较同样条件下镀制银膜的抛光良好微晶玻璃和经过精细抛光的改性 RB SiC,结果表明两者反射率相近;附着力实验表明,制备的薄膜和基底结合良好;在温度冲击实验下,制备的薄膜无龟裂和脱落.     

空间RB-SiC反射镜的表面离子辅助镀硅改性技术

针对空间用RB-SiC材料由Si\SiC两相结构引起的光学表面缺陷问题,提出了表面离子辅助沉积（IAD）硅膜的改性新方案以优化RB-SiC光学表面反射率。对厚度为10µm的IAD-Si改性层的主要性能研究显示：IAD-Si膜层为非结晶结构,能够提供较好的抛光表面,在77K-673K的热冲击下膜层稳定性良好。以Si膜的抛光机理为依据对IAD-Si改性层进行了大量抛光工艺实验和表面质量测试,给出了关键的抛光工艺参数和实验结果。通过表面IAD-Si改性及本文提出的改性层超精加工技术能够在反射镜表面得到面形精度的RMS值低于1/20λ(λ=632.8nm)且表面粗糙度的RMS值低于0.5nm的超光滑表面;与改性前相比,反射镜改性层抛光表面在360-1100 nm 波段的反射率提高了4.5%以上。     

应用表面改性技术降低烧结碳化硅反射镜的表面散射

针对烧结碳化硅在制作过程中形成的孔洞缺陷会造成严重的反射镜表面散射问题,提出了用等离子体辅助沉积技术镀制硅表面改性层来消除表面缺陷以降低反射镜的表面散射。应用扫描电子显微镜测量了未改性的烧结碳化硅试片,并分析了表面散射成因。搭建了总积分散射仪,测试了改性前后的烧结碳化硅试片及抛光良好的K9玻璃试片的总积分散射。结果显示:烧结碳化硅试片改性前后的总积分散射分别为3.92%和1.42%,K9玻璃的总积分散射为1.36%。使用原子力显微镜测试了烧结碳化硅试片改性抛光后表面和K9试片表面的均方根粗糙度,结果分别为1.63nm和1.04nm,证明了改性后的烧结碳化硅试片消除了表面缺陷,显著地降低了表面散射,表面光学性能与抛光良好的K9玻璃接近。     

表面改性非球面碳化硅反射镜的加工

为了获得高质量光学表面的非球面碳化硅(SiC)反射镜,对碳化硅反射镜表面改性技术以及离子束辅助沉积(IBAD)Si改性后的非球面碳化硅反射镜的加工技术进行研究。首先,简要介绍了碳化硅反射镜表面改性技术以及本文所采用的离子束辅助沉积(IBAD)Si的改性方法。然后,通过采用氧化铈、氧化铝以及二氧化硅等各种抛光液对离子束辅助沉积(IBAD)Si的碳化硅样片进行抛光试验。试验结果表明氧化铈抛光液的抛光效率较高,使用二氧化硅抛光液抛光后的样片表面质量最好。最后,在上述实验的基础上,采用计算机控制光学表面成型（CCOS）技术对尺寸为650mm×200mm的表面改性离轴非球面碳化硅(SiC)反射镜进行加工,最终的检测结果表明离轴非球面碳化硅(SiC)反射镜实际使用口径内的面形精度（RMS值）优于λ/50（λ=0.6328μm）,表面粗糙度优于1nm（Rq值）,满足设计技术指标的要求。     

SiC反射镜表面改性对TMC光学系统信噪比的影响

SiC（Silicon Carbide）反射镜由于固有的缺陷,在使用时会影响反射式光学系统的信噪比。采用表面改性技术后,Wyko轮廓仪测试表明SiC反射镜的粗糙度由10.42nm（Ra）降低到了0.95nm（Ra）,镀制了银反射膜和增强膜后,主镜、次镜、三镜及折叠镜在0.5μm-0.8μm的可见光波段反射率＞98%。计算的结果表明应用了表面改性技术后TMC反射式光学系统的信噪比提高了5%以上。     

磨料混合对硅通孔铜膜抛光效果的影响*

磨料的粒径分布严重影响铜膜抛光效果，单一粒径磨料在抛光过程中，部分较大或较小磨料的作用难以准确评估。针对这一问题，采用不同且粒径相近（40、60和80 nm）的磨料混合来表征反映粒径分散性对铜膜抛光的影响，研究单一磨料、2种和3种粒径磨料混合的抛光液对硅通孔铜膜抛光的影响。结果表明：在相同质量分数条件下，不同粒径磨料混合能提高铜膜抛光速率和改善表面质量；2种粒径磨料混合时，粒径差距越大，则抛光速率越快；3种粒径磨料混合时其抛光速率和抛光表面质量优于单一粒径和2种粒径混合，当40、60和80 nm 3种粒径磨料的比例为1∶3∶2时，抛光效果最好。建立铜片与抛光垫之间磨料分布的物理模型，揭示混合磨料提高铜膜去除速率的机制，计算出磨料与铜片的接触面积。     

磁控溅射MoS2薄膜的生长特性研究

利用非平衡磁控溅射技术制备出二硫化钼薄膜,并通过扫描电子显微镜和X射线衍射仪研究了工作气压和沉积时间对薄膜表面形貌和结构的影响及其演化规律。实验结果表明,在小于0.40 Pa的气压下,沉积MoS2薄膜的（002）面平行于基体表面,而在高于0.60Pa的高气压下,膜层的（002）面垂直于基体表面.在沉积初期,无论工作气压的高低,薄膜均按（002）基面的方式生长;在沉积后期,低气压下形成的薄膜仍按（002）基面方式生长,而在高气压下薄膜将转向以（002）基面与（100）或（110）棱面联合的方式生长。薄膜的表面形貌、微观结构,与薄膜的生长速率和沉积粒子的能量有关。     

金刚石涂层机械密封环的制备与抛光特性研究

为延长机械密封环的工作寿命,采用热丝化学气相沉积法在碳化硅陶瓷机械密封环工作表面涂覆具有耐磨减摩特性的、厚度30~50 μm微米金刚石（MCD）、纳米金刚石（NCD）和微纳米金刚石（MNCD）薄膜。分析结果表明：MCD薄膜的拉曼光谱具有明显的多晶金刚石特征峰,NCD和MNCD薄膜的拉曼光谱中出现了代表石墨和不定型碳的G峰和D峰。利用平面抛光实验,对比MCD、NCD和MNCD涂层机械密封环后续处理的抛光特性。实验结果表明：MNCD涂层抛光效率高且耐磨损性能优异,其综合使用性能优于MCD和NCD涂层,更适合涂覆在机械密封环表面,以增强其耐磨损性能。     

钼基体上钼-硅-氮涂层的制备与高温抗氧化性能

采用氨解渗氮法和熔盐渗硅法在钼基体上制备了钼-硅-氮涂层,利用SEM、XRD研究了涂层的微观结构、元素分布及物相组成,并分析了其在1 600℃的抗高温氧化性能。结果表明:钼基体上的钼-硅-氮涂层由MoSi2和Si3N4相组成,高温氧化时表面可形成致密的SiO2膜,在1 600℃循环氧化寿命达48h。     

Effect of Surface Roughening of Substrate Steel on the Improvement of Delamination Strength and Tribological Behavior of Hydrogenated Amorphous Carbon Coating Under Lubricated Conditions

The adhesion strength of diamond-like carbon (DLC) coatings is an obstacle in efforts to improve the reliability of coated products. It is generally believed that the roughening of the substrate surface improves the adhesion between a substrate and coating. The effect of surface roughening of the substrate on the delamination strength of DLC coating and the tribological behavior under lubrication were studied. Five types of roughened substrates were prepared by a wet blast device with differing materials, shapes, and sizes of the shot particles. A hydrogenated DLC film was deposited using plasma-enhanced chemical vapor deposition on the roughened substrates. The tribological properties were investigated under air and lubrication with pure water or n-decane. It was found that the delamination strength of the DLC coating could be improved by roughening the substrate surface, especially by spherical particles. It was also found that slight polishing of either the DLC surface deposited on the rough substrate or the roughened substrate before deposition significantly reduced the wear of the counter surface. The remaining chemical element of alumina particles on the roughened surface affected the delamination strength of the DLC coating.     

一种提高空间用RB-SiC基底反射镜表面改性效果的有效方法

为了满足空间应用中大口径、复杂轻量化结构的RB-SiC基底反射镜对高性能表面质量的应用需求,针对RB-SiC基底的特性,改进了表面改性工艺方法。采用高能量考夫曼离子源辅助,预先对基底进行碳化和加镀C缓冲层,并制备Si改性涂层的方法对RB-SiC基底进行了表面改性。测试结果表明：与单纯霍尔离子源辅助方法相比,此工艺方法制备的Si改性涂层生长得更加致密、均匀,抛光特性良好;改性抛光后表面粗糙度（rms）降低到0.635nm,已达到S-SiC基底的水平;改性后RB-SiC基底的反射率明显提高,已经达到抛光良好的微晶玻璃的水平。结果表明该工艺方法是提高RB-SiC基底表面改性效果的一种十分合理有效的方法。     

Development of a one-dimensional differential deposition system for X-ray mirror figure correction

A thin-film deposition system was developed for the surface coating of X-ray mirrors of up to 1 m in length. With two coating process areas and four sputtering cathodes, various combinations employing a single layer, multilayered, and co-sputtered thin films are possible. Furthermore, it is possible to correct and modify the mirror surface shape by controlling the speed of the substrate stage. In this study, to evaluate the performance of the proposed coating system, the static coating distribution was measured to check the vertical direction. In a 10 mm area, a 0.9% peak-to-valley error and 0.2% root mean square error occurred. A differential deposition test was also performed for the horizontal direction (stage scan direction). In this study, arbitrary shapes were deposited on 100-mm and 400-mm-long mirrors. After removing the measurement error, the deposition error was less than 1 nm (peak-to-valley). The results demonstrate that this system can correct the surface of an X-ray mirror with ultra-high precision.     

NAK80模具钢表面激光熔覆钴基合金涂层的组织和摩擦磨损性能

采用激光熔覆方法在NAK80模具钢表面制备钴基合金熔覆层,用扫描电镜、X射线衍射仪分析了熔覆层的显微组织,通过干滑动摩擦试验研究了熔覆层的摩擦磨损性能,分析了其磨损机制,并用三维表面形貌仪观察磨损试样的表面形貌。结果表明:熔覆层的主要组成相为Cr23C6、Co3Mo2Si、MoC、FeCr和γ-Co;熔覆层由涂层与基体界面处的平面晶区、涂层中部的胞状树枝晶区和表层的网状等轴晶粒区组成;经激光熔覆处理后的NAK80模具钢表面硬度和耐磨性得到了显著改善,与NAK80模具钢相比,熔覆层表面的平均摩擦因数降低了约34%,比磨损率下降了约91.3%;熔覆层的磨损机制为粘着磨损和轻微的显微切削。     

Study of tribological properties of coating/substrate system in micrometer and nanometer scales with a scanning probe microscope

We have used a scanning probe microscope equipped with a custom made diamond tip to study tribological properties of an inorganic–organic hybrid Si, O, H, and C coating produced by plasma enhanced chemical vapor deposition (PECVD) on siloxane/acrylic/polycarbonate multilayer substrates and on glass substrates. The micro indentation hardness and micro mar resistance were measured under different normal forces, and the critical loads for cracking, delamination, and chipping were evaluated. The effects of substrate, coating thickness, and interfacial adhesion on tribological properties of the coating/substrate systems are discussed. The results show that increasing coating thickness and strengthening interfacial adhesion can effectively inhibit cracking, delamination, and chipping of the coating/substrate systems under wear. Improving the physical properties of the PECVD coating and substrate, such as enhancing elastic recovery, reducing plasticity and brittleness, and matching the properties of coating and substrate better can improve the wear resistance of the systems further.     

Application of cold spraying for flux-free brazing of aluminium alloy 6060

In the present study, samples of aluminium alloy 6060 were coated by cold spraying with a powder of brazing alloy Al12Si. The influence of the process gas temperature on particle velocities and coating build-up was investigated. The coated samples were heat-treated in air and under argon atmosphere to investigate the wetting behaviour of the deposited Al12Si and the diffusion processes between Al12Si coatings and substrates. Coated samples were brazed flux-free under argon atmosphere by an induction heating system. The microstructure of the coated, heat-treated, and brazed samples was investigated. The shear strength of the brazed joints was determined. The results show that the brazing alloy Al12Si could be very well deposited on the substrate by cold spraying. The particle velocity increased with increasing process temperature. Correspondingly, the thickness of Al12Si coatings increased with increasing process temperature. The heat treatments showed that a very good metallurgical bond between the Al12Si coatings and the substrate could be realized by the deposition using cold spraying. The coated samples could be well brazed without fluxes. The coating thickness and overlap width influenced the shear strength of the brazed joints. The highest shear strength of brazed joints amounts to 80 MPa.     

Application of cold spraying for flux-free brazing of aluminium alloy 6060

In the present study, samples of aluminium alloy 6060 were coated by cold spraying with a powder of brazing alloy Al12Si. The influence of the process gas temperature on particle velocities and coating build-up was investigated. The coated samples were heat-treated in air and under argon atmosphere to investigate the wetting behaviour of the deposited Al12Si and the diffusion processes between Al12Si coatings and substrates. Coated samples were brazed flux-free under argon atmosphere by an induction heating system. The microstructure of the coated, heat-treated, and brazed samples was investigated. The shear strength of the brazed joints was determined. The results show that the brazing alloy Al12Si could be very well deposited on the substrate by cold spraying. The particle velocity increased with increasing process temperature. Correspondingly, the thickness of Al12Si coatings increased with increasing process temperature. The heat treatments showed that a very good metallurgical bond between the Al12Si coatings and the substrate could be realized by the deposition using cold spraying. The coated samples could be well brazed without fluxes. The coating thickness and overlap width influenced the shear strength of the brazed joints. The highest shear strength of brazed joints amounts to 80 MPa.     

Mechanical properties of amorphous carbon nitride thin films prepared by reactive magnetron sputter-deposition

Nanoindentation hardness and compressive stress in amorphous carbon nitride thin films prepared by unbalanced magnetron sputter-deposition were studied. The coating hardness and compressive stress were found to be strongly dependent on processing parameters such as substrate bias and nitrogen partial pressure. Under optimized deposition conditions, carbon nitride thin films with nanoindentation hardness about 25 GPa have been coated onto Si wafers and M2 steels. A strong correlation between coating hardness and compressive stress in the coating was observed.     

基体表面粗糙度对磁控溅射TiN涂层界面结合力的影响

利用球与平面的赫兹接触应力分布的经验修正公式∧［1］,对磁控溅处理前的基体表面粗糙度对沉积层和基体的界面结合力进行了研究,并和其他涂层界面结合力的测量方法方法进行了比较。结果表明：基体表面粗糙度对界面结合力有很大影响,表面粗糙度的改善有利于TiN层/基体的界面结合力的提高,同时改善了TiN层的摩擦学性能。