含Mo的PVD涂层结构及其摩擦学特性的研究进展

从含Mo元素的代表性涂层入手,综述了二元、三元再到多元含Mo系列PVD涂层的研究现状和进展,探究了不同元素添加、不同制备参数等对涂层微观结构、力学性能和摩擦学性能等的影响。在涂层组分从二元发展到多元的过程中,改变掺杂元素种类、含量,制备参数会引起涂层微观结构的变化进而提升涂层力学性能和摩擦学性能。涂层性能的改善,有利于增强对机械设备中关键传动零部件的保护,延长机械设备使用寿命,对军工及社会发展具有重大意义。     

金属陶瓷及硬质合金表面CVD/PVD涂层的摩擦与切削性能

为研究涂层沉积方式对金属陶瓷和硬质合金性能的影响,采用粉末冶金技术制备了Ti(C,N)基金属陶瓷和YT15硬质合金,在基体表面先后采用CVD和PVD制备涂层。采用SEM、EDS等手段对涂层的微观组织和元素含量进行分析,并对涂层试样进行划痕、摩擦因数、切削性能检测。结果表明,通过复合CVD+PVD工艺,CVD涂层和PVD涂层结合良好。不论是金属陶瓷还是硬质合金,CVD涂层的膜基结合力和摩擦因数均为最大,PVD涂层最小,复合CVD+PVD涂层介于两者之间。对于金属陶瓷和硬质合金而言,复合CVD+PVD涂层的切削性能最好,CVD涂层最差,PVD涂层介于两者之间。切削过程中的磨损机理主要是氧化磨损和磨粒磨损。     

切削刀具PVD涂层材料的研究进展

随着PVD涂层技术的不断进步,切削刀具涂层材料由简单的单层二元向着多层多元纳米复合方向发展,并成为研究的热点。纳米复合涂层在成分上趋于多元化,结构上趋于多层化、梯度化、复合化,功能上软/硬结合。虽然目前大多数仍停留在实验阶段,但由于其具备高硬度、高耐磨性、高层间结合强度等综合机械性能,已经显示出了良好的应用前景。     

矿用减速器太阳轮齿面PVD表面改性的研究

针对矿用减速器太阳轮接触强度最小安全系数通常小于1.25,即可靠度不理想的问题,对太阳轮常用材料17CrNiMo6进行物理气相沉积(PVD)处理。将其表面附着TiN涂层、TiC复合层,并对这2种涂层进行厚度、硬度、密着力、EDS分析。研究表明:齿面进行PVD表面改性虽然具有粗糙度良好、涂层均匀以及密着力好等优点,但其硬度有所降低。     

Characterization and properties of PVD coatings applied to extrusion dies

The paper presents the research results on the microstructure, mechanical and tribological properties of coatings deposited by cathodic arc evaporation methods on the X40CrMoV5-1 hot work tool steel substrates as well as the possibility to employ the finite element method for evaluation of stresses in the investigated coatings. The tests were carried out on CrAlSiN and CrN coatings. The coatings demonstrated a dense cross-sectional morphology as well as good adhesion to the substrate. The critical load L_C2 lies within the range 54-55 N, depending on the coating type. The investigated coatings have the potential to increase the service life of an extrusion die by orders of magnitude as compared with uncoated steel.     

DLC涂层应用于活塞环

本文介绍了采用PVD处理方法获得的DLC涂层,针对DLC涂层应用于活塞环,提高活塞环耐磨、减摩性能做了重点介绍,并叙述了该领域的发展现状及趋势。     

DLC涂层应用于活塞环

本文介绍了采用PVD处理方法获得的DLC涂层，针对DLC涂层应用于活塞环，提高活塞环耐磨、减摩性能做了重点介绍，并叙述了该领域的发展现状及趋势。     

The effect of geotextile reinforcement and prefabricated vertical drains on the stability and settlement of embankments

The construction of four dikes on deep strata of very soft clay has required the application of several measures to improve the performance of the foundation, such as very wide berms, basal geotextile reinforcement and prefabricated vertical drains (PVDs). In order to control the rate of construction, the foundation and the dikes have been monitored with settlement plates, topographic stakes, inclinometers and piezometers. The use of back-analysis has allowed finding the adequate material model, the smearing of drains and the coefficient of secondary compression necessary to attain a good agreement between the measurements supplied by the instrumentation and the calculated values obtained with an elastic-viscoplastic (EVP) finite element (FE) program. Both the geotextile reinforcement and the PVDs produce an important increase in the safety factor (SF). The PVDs produce a significant acceleration in settlements, but the influence of the geotextile in the settlements is negligible. The combined use of the geosynthetic reinforcement and PVDs enhances embankment performance substantially more than the use of either method of soil improvement alone. The importance of flow in the results has been established.     

Enhanced Performance of Nanostructured Coatings for Drilling by Droplet Elimination

Cutting tool performance is mainly characterized by material substrate, cutting edge geometry, and coating, and also by a good choice of the cutting parameters, mainly cutting speed, depth of cut, and feed. In drilling a good choice of substrate/coating can reduce production costs per hole cut by 50%. Coatings evolution has gone from monolayer to nanostructured and/or nanometric-scale multilayer coatings. These are used because of their high hardness, good corrosion and oxidation resistance, and thermal stability. Cutting edge preparation on the one hand and droplet elimination after the coating process on the other are important issues for reaching a good tool/coating performance, being a key issue. In this article a series of coatings for drilling low and medium carbon alloyed steels are presented, along with their performance. Validation tests were carried out on steel 42CrMo4, very often used in the automotive sector. Seven coatings were tested, including AlCrSiN, µAlTiN, TiAlCrN, AlTiCrN, AlCrN, AlTiSiN, and TiAlSiN. Flank wear, evolution of drilling thrust force and torque, damage on cutting edge faces on primary cutting edge, and behavior of drill bit secondary edges were studied. A final elimination of droplets by drag grinding was performed in several cases. Process monitoring, scanning electron microscope (SEM) microscopy, and energy-dispersive X-ray (EDX) analysis were used, concluding that the best results were for µAlTiN, TiAlSiN, and AlTiSiN. Reasons for the good behavior are the good surface finishing after droplet elimination and the high thermal stability of these protective layers.     

Cavitation erosion resistance parameter of hard CAVD coatings

Nowadays the most machining tools are coated with hard coatings to prolong their lifetime and to improve their working efficiency. They are very often used for high wear applications, where they are subjected to cyclic impact loading. Main benefits of hard coatings are based on the combination of high hardness and toughness, properties that are especially important in the conditions of dynamic impact wear when high cyclic local loading is the main cause of coating degradation. A cavitation test can be a useful tool for studies of plastic deformation, crack initiation and propagation in thin hard coatings. Cavitation damage is caused by repeating action of imploding cavitation bubbles in the vicinity of solid surface.