Effect of Rare Earth Element Cerium on Mechanical Properties and Morphology of TiN Coating Prepared by Arc Ion Plating

TiN coatings were deposited on polished substrates of W18Cr4V high speed steel by means of vacuum arc ion plating. The effect of cerium on adhesion between TiN coating and substrate was studied. The microstructures and composition of TiN coatings were also investigated by means of scanning electron microscope (SEM), Auger electron spectroscopy (AES), and X-ray diffraction (XRD) technique. It was found that cerium is an effective modifying agent and the addition of suitable amount of cerium to TiN coatings can produce relatively excellent properties such as micro-hardness, wear resistance, oxidation resistance and porosity. The experimental results show that the added cerium in TiN coatings makesa contribution to form the preferred direction along with a (111 ) or (222) close packed face, which may be one of the reasons that improves some properties mentioned above.     

Ti/Al Interaction and Austenite Grain Control in Crankshaft Manufacturing with 38MnSiVS5 Steel

38MnSiVS5 steel is similar to 38MnVS6 steel (EN), the difference being the addition of a small Ti content. Typical Ti and Al contents in the chemical composition of 38MnSiVS5 steel are Ti=0.020 and Al=0.035 mass%. Both elements combine easily with nitrogen, especially Ti, and it has been observed that relatively high Al levels are harmful for austenite grain size control at reheating temperatures. In this work 38MnSiVS5 steel is used to manufacture a large number of castings, varying only the Ti and Al contents and obtaining ingots with a different Ti/Al ratio in each case. The results show that abnormal growth of the austenitic grain occurs irrespective of the Ti and Al contents, due fundamentally to the partial dissolution and coarsening of TiN precipitates. However, the steels with high Al contents present worse behaviour due to the formation of a second type of precipitates, namely AIN, which quickly dissolve between 1000 and 1100°C, causing a drastic decline in local pinning forces that gives rise to more pronounced abnormal growth of the affected grains.     

等离子体浸没式离子注入-离子束增强沉积TiN膜研究

本文采用一种新型的等离子体浸没式离子注入 离子束增强沉积的技术(PIII IBAD),在Cr12MoV钢基体上制备出了TiN膜,对沉积膜的组织进行了光电子能谱分析,并对沉积膜进行了硬度检测、摩擦试验及磨痕形貌分析。试验结果表明,沉积膜中的组织为TiN、TiO2和Ti2O3,TiN膜具有高达Hv3200的高硬度和极其优良的摩擦性能。     

PREPARATION OF TiN FILMS BY N_2 ASSISTED Xe~+ ION BEAM ENHANCED DEPOSITION AND THEIR MECHANICAL PROPERTIES

A new method for preparation of hard TiN films has been developed by using electronbeam evaporation-deposition of Ti and bombardment with 40 keV Xe~+ ion beam ina N_2 gas environment.The synthesized TiN films were superior to PVD and CVDones in respects of improved adhesion to substrate and low preparing temperature.Theyexhibited good wear resistance and high hardness up to 2200 kg/mm~2.Some industrialapplications have been reported.     

TEM and DFT investigation of CVD TiN/κ-Al2O3 multilayer coatings

This paper investigates the interfacial structure in hot-wall CVD TiN/κ-Al₂O₃ multilayer coatings using both HREM and DFT modeling. Two multilayers with different thicknesses of the TiN layers (50 and 600 nm) separating the κ-Al₂O₃ layers are analyzed. The general microstructure of the two multilayers is relatively similar. The TiN layer in the thicker TiN/κ-Al₂O₃ coating is thick enough to be several TiN grains high. This means that epitaxial columns, which are often found in the thinner TiN/κ-Al₂O₃ coatings, are not present. However, the orientation relationships at the TiN/κ-Al₂O₃ interfaces are the same in both multilayers. The HREM investigations show that κ-Al₂O₃ (001) planes can grow directly on flat (111) TiN faces, without any other phases or detectable amounts of impurities, such as sulphur, present. Where the TiN layers are more curved, γ-Al₂O₃ can be grown, at least partly stabilized by the cube-on-cube orientation relationship between γ-Al₂O₃ and the underlying TiN. The DFT calculations show very similar adsorption strengths for an O monolayer positioned on Ti-terminated TiC(111) and TiN(111) surfaces, with preferred adsorption in the fcc site. O adsorption on N-terminated TiN(111) is much weaker, with preferred adsorption in the top site. Calculated elastic-energy contributions yield a higher stability for κ-Al₂O₃ on TiN(111) than on TiC(111) and a higher stability for κ-Al₂O₃ than for α-Al₂O₃ on both TiC and TiN. This indicates that the observed higher stability of κ-Al₂O₃ on TiC(111) than on TiN(111) is not due to the lattice mismatch, while the preferred epitaxial growth of κ-Al₂O₃ over α-Al₂O₃ can be partly attributed to the mismatch.     

New type of tin support for hydroprocessing catalyst

TiN supported molybdenum sulfide catalysts showed much higher activity for cleavage of C-C bonds than oxide supported molybdenum sulfide catalysts, indicating the possibility of a new generation of supports for hydroprocessing catalysts.     

硬质合金表面热阴极离子镀TiN涂层抗氧化性研究

利用热阴极离子镀技术在牌号为ZK1的硬质合金表面镀制TiN硬质涂层,并在300℃至700℃空气环境下进行抗氧化实验。运用XRD和XPS对涂层进行微观结构和成分的分析,并用SEM进行涂层断口的观察,最后采用显微硬度计和自动划痕仪分別对涂层的显微硬度和膜基结合力进行了检测。实验结果表明,涂层厚度约为5μm,涂层成分以TiN为主,平均显微硬度达2388HV,结合力最大达85N。随着氧化温度的升高,在涂层表面先后形成了TiNxOy、TiO2,涂层的显微硬度和膜基结合力都呈下降趋势并在550℃处剧烈下降。     

反应烧结制备Ti_2AlN-TiN复合材料

采用2Ti/2Al/3TiN粉体为原料,通过反应热压烧结,以制备Ti2AlN-TiN复合材料。采用X射线衍射（XRD）、场发射扫描电镜（FE-SEM）结合能谱仪（EDS）分析试样。研究结果表明,在1350℃保温2h,压力为30MPa,可烧结得到组织细小、致密的Ti2AlN-TiN复合材料。材料中层片状Ti2AlN晶粒长约5m,TiN晶粒大小为1~2m。复合材料具有良好的机械性能,其显微硬度与弯曲强度分别达8.57GPa和450MPa。     

高速钢表面PN＋PVD复合处理工艺和性能研究

采用多弧离子镀设备,在高速钢W18Cr4V上先进行等离子氮化,再沉积TiN薄膜,研究了不同渗氮温度和时间对PN＋TiN薄膜组织和性能的影响。结果表明,温度为500℃左右和时间为2h以上条件下对W18Cr4V进行渗氮处理后再沉积TiN薄膜,可以得到最佳的薄膜表面显微硬度（1800～2000HV0.05）和膜／基结合力（50N）,涂层耐磨性也得到明显提高。     

脉冲高能量密度等离子体沉积氮化钛膜的结合强度

本文用脉冲高能量密度等离子体技术，在室温条件下，成功地在ＧＣｒ１５钢表面沉积了性能良好的氮化钛薄膜。用自动划痕试验仪测量了氮化钛薄膜的结合强度。研究结果表明：表征薄膜结合强度的临界载荷有相当高的值；氮化钛薄膜的临界载荷随脉冲轰击次数、内外电极的电压变化而变化。对沉积膜结合强度的这些变化给予了理论上的解释与讨论。