不同厚度TiN薄膜摩擦学性能研究

用中频磁控溅射镀膜机制备得到了各种厚度不同的TiN薄膜,研究了TiN薄膜的纳米硬度、膜基结合力、摩擦系数以及综合摩擦磨损性能。实验表明:用中频非平衡磁控溅射制备的TiN薄膜表面光滑,缺陷较少。但是,随着沉积厚度的增加,薄膜可能因内应力过大导致薄膜脱落;薄膜厚度随沉积时间延长而增大,但薄膜纳米硬度基本不变,约为21 GPa;划痕实验临界载荷随薄膜厚度增大逐渐增大,膜基结合力有所增强;但是如果薄膜太厚,可因内应力增大而膜基结合力减弱;材料摩擦系数随摩擦磨损实验所加载载荷不同而不同。在不同载荷下,所得摩擦系数分别对应薄膜、过渡层和基体材料的摩擦系数。在20 g、50 g、100 g不同载荷下,薄膜、过渡层和基体的摩擦系数分别为0.05、0.41、0.69;随薄膜厚度增加,在所加载载荷下,材料的综合抗磨损性能增强。     

As40Se60硫系玻璃基底薄膜制备与应力分析

硫系玻璃是一类优秀的红外光学镜片材料,但其热膨胀系数较大,与Si、Ge等红外光学材料相比,硫系玻璃镜片在镀膜过程中产生的残余应力较大,镀膜后面形变化较大。研究膜层中应力并优化应力的控制方法,可以提高薄膜的力学性能。本文通过测量在As₄₀Se₆₀硫系玻璃上镀膜前后基底的变化量来研究基底上不同材料膜层的残余应力情况,同时使用ANSYS软件对As₄₀Se₆₀/ZnS/Ge/ZnS/Ge/ZnS/YbF₃/ZnS红外光学镜片膜系结构的热应力进行理论计算与仿真,验证了模型的合理性。分析了膜系结构中热应力在轴向与径向分布情况,结果显示：轴向热应力主要集中在膜层部分,表面膜层的热应力最大;径向热应力呈均匀分布,在边缘发生突降。分析了最外层保护膜的热应力与沉积温度、相邻膜层、不相邻膜层和基底的关系,结果表明：沉积温度在110℃到200℃的范围内,保护膜的热应力与沉积温度成正比;相邻膜层和不相邻膜层的厚度和材料均不影响保护膜的热应力;基底的厚度会对保护膜的热应力产生影响。     

CVD样品台旋转对沉积金刚石涂层的影响

以CH3COCH3和H2为反应气源,利用热丝化学气相沉积(HFCVD)方法,通过改变样品台的旋转频率在YG6硬质合金(WC-6wt; Co)基体上沉积金刚石涂层.利用X射线衍射分析YG6硬质合金表面沉积金刚石涂层物相,通过扫描电子显微镜和压痕试验机分析金刚石涂层的表面形貌、沉积厚度和膜基结合性能,考察了样品台旋转频率对沉积金刚石涂层结构与性能的影响,以确定最佳的样品台旋转频率.结果 表明,在固定沉积工艺参数条件下,当样品台的旋转频率为2次/h时,在YG6硬质合金基体上沉积的金刚石涂层具有较优的晶粒和更均匀致密的聚晶结构以及更高的膜-基结合力.     

(Ti1-xAlx)N硬质涂层的研究进展

TiAlN作为一种三元复合纳米涂层材料,具有非常好的性能.该涂层克服了TiN涂层所存在的一些缺陷,其硬度远远高于TiN涂层,最高可达47GPa, 并且具有很好的热稳定性,在700℃高温下仍很稳定,而TiN涂层在500℃时就已被氧化.TiAlN涂层还具有抗磨损,摩擦系数小,热膨胀系数及热传导系数低等特性,这些特性与涂层中Al含量的多少有关,Al含量的改变会导致涂层微观结构的改变,从而使其性能发生变化.氮分压和基底温度对TiAlN涂层的性质有着极其重要影响.本文结合国内外对TiAlN涂层的最新研究进展,对TiAlN涂层的应用,制备方法,结构,抗氧化性及硬度作了简要论述.     

（Ti（1-x）Alx）N硬质涂层的研究进展

TiAlN作为一种三元复合纳米涂层材料,具有非常好的性能.该涂层克服了TiN涂层所存在的一些缺陷,其硬度远远高于TiN涂层,最高可达47GPa, 并且具有很好的热稳定性,在700℃高温下仍很稳定,而TiN涂层在500℃时就已被氧化.TiAlN涂层还具有抗磨损,摩擦系数小,热膨胀系数及热传导系数低等特性,这些特性与涂层中Al含量的多少有关,Al含量的改变会导致涂层微观结构的改变,从而使其性能发生变化.氮分压和基底温度对TiAlN涂层的性质有着极其重要影响.本文结合国内外对TiAlN涂层的最新研究进展,对TiAlN涂层的应用,制备方法,结构,抗氧化性及硬度作了简要论述.     

前驱体转化法制备TiSi2/YSZ陶瓷涂层

采用聚硅氮烷前驱体作为基体,添加惰性填料(YSZ)和活性填料(TiSi2)制备涂层浆料,在310s不锈钢表面利用前驱体转化法制备TiSi2/YSZ陶瓷涂层.通过TGA、XRD和SEM对涂层的物相组成和微观形貌进行了表征,并研究了TiSi2含量对涂层的隔热性能以及耐高温性能的影响.结果表明,所制备的涂层厚度在15～35μm之间,由于前驱体树脂裂解过程中的体积收缩,未添加TiSi2的涂层表面分布有大量裂纹且涂层部分脱落.裂解过程中,TiSi2氧化生成TiO2与SiO2后可使TiSi2体积膨胀,弥补了前驱体树脂的体积收缩.因此随着TiSi2含量的增加,涂层脱落面积减少,表面裂纹密度降低,当TiSi2的体积分数达41;时,涂层内部无裂纹产生,该涂层样品在1200℃氧化25 h后金属基底氧化增重降低88.8;,并表现出良好的隔热性能和抗热震性能.     

单晶炉观察窗工作热应力模拟

以单晶炉壁热应力为研究对象,分析了单晶炉观察窗焊接接头冷却水泄漏机理,建立了三维稳态温度场和弹塑性应力场有限元模型,对十二种组合结构的观察窗进行了工作热应力模拟,比较了平面和椭圆型炉盖封头、长条形和方圆形观察窗焊缝的热应力状态,探讨了形状、单双面焊接和温度对热应力影响趋势.结果 表明,内外壁横截面均为正方形或矩形的两种窗形焊缝的热应力极值最大;增加副焊缝成为双面焊时,主焊缝的应力分布几乎没有变化,新增加的焊缝约束对其影响甚微;工作温度越高,焊缝的热应力越大.因而,宜选用圆形窗或者内壁带圆弧的长条窗,施加双面焊,避免窗体冷却水温超过规定值.这些措施成功解决了观察窗在样机试验时能正常工作,出厂使用时寿命短频繁漏水的问题.     

PVP对碳热还原氮化法制备TiN薄膜的影响

采用四氯化钛的无水乙醇溶液为钛源,以聚乙烯吡咯烷酮(PVP)为成膜助剂及还原助剂,利用碳热还原氮化技术,在N2气氛下经1300℃进行还原氮化5h制备出TiN薄膜.采用XRD和SEM研究了PVP分子量及其用量对TiN薄膜微观结构的影响.结果发现,随着PVP分子量增大,薄膜中TiN晶体沿(111)面择优生长趋势减小,PVP分子量为1300000时薄膜中TiN晶粒尺寸较大,晶界减少.当PVP用量由钛/碳摩尔比为1∶10增加到1∶12时,TiN薄膜裂纹减少,而增至1∶14时,TiN薄膜中气孔增多.TiN薄膜的生长过程为:TiN颗粒状晶核逐渐生长成棒状,然后继续生长形成片状三角形或六边形,最后呈现出三角锥或六棱台形.     

PVT法生长SiC过程生长界面形状对热应力的影响

PVT法生长SiC过程中晶体内部的热应力是其位错产生的主要原因,而生长界面的形状对晶体热应力及缺陷的产生都有一定影响.本文对不同生长界面晶体的温场及应力场进行了数值分析,结果显示相对于凸出及平整界面的晶体,微凹界面晶体的轴向温差最小,同时产生缺陷的切应力Τrz及引起开裂的径向正应力σrr值都为最小.     

pH值对金刚石表面化学镀镍的影响

本文以金刚石颗粒表面化学镀的方法镀覆镍金属层为背景,通过X射线衍射(XRD)、扫描电镜(SEN)等测试手段研究了pH值对镀层的组织、形貌及镀速的影响.结果表明:当镀液的pH值低于10.5时,镀速几乎为零,反应不能发生;pH值在10.5 ～ 12时,镀速随pH值的增加而增大,且镀速增加较快,XRD图谱中有镍峰存在,镍峰随pH值的增加而增强,基体有裸露现象;当pH值在13左右时,镀速较为稳定,镍衍射峰较强,镀层较为均匀,无裸露现象;pH值接近14时,镀层较为粗糙,且有脱落现象.在pH值等于13的条件下二次化学镀,基体表面得到的镀层厚度大约为1.5 μm,镀层致密度较好,且包覆严实.     

纳米结构TiN薄膜的制备与性能研究

利用自行研制的磁过滤等离子体设备,在室温条件下的不锈钢基底上成功地制备了性能良好的纳米结构TiN薄膜.运用原子力显微镜和X射线衍射仪对其结构和形貌进行了表征.利用纳米硬度仪测量了TiN薄膜的硬度和弹性模量.结果显示:沉积的TiN薄膜表面非常平整光滑,致密而无缺陷;硬度远高于粗晶TiN的硬度;TiN晶粒尺寸在30～50nm;沉积过程中在基底上施加的负偏压会影响纳米结构TiN薄膜的结构和性能.     

超声辅助脉冲电沉积Ni-TiN复合镀层制备工艺研究

采用超声辅助脉冲电沉积方法在45#钢表面制备NI-TiN复合镀层..利用X射线衍射仪(XRD)对复合镀层的物相组成进行检测分析,并利用原子力显微镜(AFM)、透射电镜(TEM)对Ni-TiN复合镀层的立体表面形貌及晶粒的分布进行观察分析.结果表明:当超声波功率为300 W时,所制备的Ni-TiN纳米复合镀层衍射峰强度最高,且含有Ni、TiN两相,Ni晶粒得到显著细化,TiN纳米颗粒分布较为均匀,无显著团聚现象发生.     

Electrical and optical properties of titanium nitride coatings prepared by atmospheric pressure chemical vapor deposition

In order to examine the possibility for TiN coatings to be low-E, TiN coatings were deposited on the glass substrates by atmospheric pressure chemical vapor deposition using titanium tetrachloride (TiCl₄) and ammonia (NH₃) as precursors. X-ray diffraction, sheet resistance measurement, optical transmittance spectroscopy and infrared reflectance spectroscopy were carried out to determine the relationships between the preparation parameters and the microstructure, electrical and optical properties of the coatings. The results showed that the concentration of crystals increased with increasing the substrate temperature and the flow of TiCl₄, resulting in a decrease of the electrical resistivity. The optical transmittance of TiN thin films was strongly dependent on the gas flow and the substrate temperature. Under optimum conditions, continuous polycrystalline TiN coatings with FCC structure were obtained with an electrical conductivity around 34.5 Ω/□, an optical transmittance around 50% in the visible range, and an infrared reflectance higher than 50% above 3000 nm. This indicates that TiN coated glasses may be possible candidates for high IR reflectance windows.     

Effect of substrate temperature on the properties of reactively sputtered TiN/NbN multilayers

TiN/NbN multilayer coatings were deposited with various substrate temperatures by DC reactive magnetron sputtering method onto Si (111) and glass substrates. The effect of substrate temperature on the structural and optical properties of TiN/NbN multilayers was investigated by X‐ray diffraction, X‐ray photoelectron spectroscopy, Field emission scanning electron microscopy and Photoluminescence measurements. The composition was analyzed by X‐ray photoelectron spectroscopy. X‐ray diffraction results showed that the layers crystallized in cubic structure for TiN and hexagonal structure for NbN. It was found that grain size increased with increase in substrate temperature. The surface morphology of the TiN/NbN thin films showed a dense and smooth surface with substrate temperature upto 200 °C but after 300 °C, the grains became larger and coarse surface was observed. The TiN/NbN multilayer coatings exhibited the characteristic peaks centered at 180, 210 and 560 cm^‐1. Red band emission peaks were observed in the wavelength range of 700‐710 nm. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Investigations on mechanical properties and chemical composition of thermally treated TiCx coatings on steel (CVD technique)

The described technology allows the production of dense TiC_x coatings onto steel at standard pressure. The residual stress in the coatings is a compressive one with a level of some GPa. It is lowered with an increase of the coating thickness and/or a substrate hardening. Both the residual stress level and the constitution of the contact region substrate/coating mainly influence the mechanical behaviour under external load. An occasional formation of cementite islands on the substrate surface in the initial stage of the deposition process reduces the adhesion of the coating. The coating failure of substratehardened samples has not to occur as a necessity at the contact region, but is possible also by breaking out inside the coating. Besides, the existence of voids along the contact region was observed in this case.     

金刚石膜/硅基体热残余应力场有限元分析

运用ANSYS软件建立了有限元模型,对化学气相沉积在硅基体上的金刚石膜内部和膜/基交界面处的各热残余应力分量的分布作了计算与分析.所建模型与已有的一维解析模型都能得出厚度截面上的法向应力分量的分布,且吻合较好,而前者的优点在于它还能模拟切向应力和剪应力等其它应力分量,这对分析膜/基界面的粘附与失效是至关重要的.     

Calculation of the shear stresses in (111)- and (001) semiconductor substrates with film edges

Assuming a film-edge induced stress distribution in an isotropic crystal, the shear stresses in the glide systems of a diamond-type semiconductor substrate are calculated. Quantitative information on magnitude and position of the respective shear stress maxima is obtained in dependence on crystal orientation and technologically relevant film configurations.     

Influence of sol and substrate chemistry on the formation of sol-gel derived coatings

In this study several types of coating sol to substrate wetting behaviors were observed. These wetting behaviors, which influence final coating quality, are a complicated function of sol and substrate chemistry. Coating quality could be altered considerably by the choice of substrate, sol additives, or sol ageing. The most dramatic improvements in unfired coating quality were obtained by additions of titanium alkoxide to the sol. This improvement is explained in terms of a sol/substrate charging mechanism.     

原位氮化法制备TiN纳米粉体

用溶胶凝胶法合成的纳米TiO2粉体作为原料,将该粉体在氨气中进行原位氮化制备了TiN纳米粉体.用XRD,TEM,化学分析等手段对合成的TiN纳米粉体的物相组成、形貌、成分进行了分析.实验分析表明:在1000℃和1100℃下分别氮化5h,可以制备粒径大约为40nm和80nm的TiN粉体,其TiN的含量分别为95.40;和98.37;;而在1000℃条件下氮化时间减少到2h时,TiN的含量仅为58.36;.氮化温度和氮化时间是合成纳米TiN的重要因素,提高合成温度和延长氮化时间均可形成纯度较高的TiN纳米粉体,但延长氮化时间更有利于获得粒径小的氮化钛粉体.