PVD coating

This study has been conducted to evaluate the influence of temperature and substrate roughness on microstructure and properties of electron beam physical vapour deposition NiCrAlY coating. The chemical composition was adjusted by continuous feeding in the molten pool. The results show that the coating roughness generally increased with an increase in the substrate roughness and decrease in its temperature. However, in rough substrates, coating roughness were lower than that of the substrates, and in samples with a lower substrate roughness, coatings had a greater roughness level in comparison with their corresponding substrates. The polished samples with the lowest level of substrate roughness had narrower columns, and by an increase in the roughness of the substrate, the columns became thicker. The optimised conditions in terms of microstructure and adhesion strength were observed in the sample with the roughness level of Ra = 0·02 μm and the homologous temperature of θ = 0·44.

The aim of the present work is to identify an environmentally clean coating process that will present lower influence in the Ti–6Al–4V fatigue strength. Axial fatigue tests of Ti–6Al–4V alloy TiN, CrN and WC:H (tungsten containing diamond-like carbon) Physical Vapor Deposition (PVD) coated was evaluated. Decrease in fatigue life was observed for coated specimens in comparison to base metal. Scanning Electron Microscopy technique was used to observe crack origin sites and coating thickness. DLC coating provides higher Ti–6Al–4V alloy PVD coated fatigue strength due to lower defects presence and the chromium interlayer, which acts as a barrier to fatigue crack propagation.

http://pandu-equator.com/prefabricated-vertical-drain-pvd/
1. Pendahuluan Suatu struktur bangunan karena alasan teknis, ekonomi, sosial, atau strategis terpaksa harus didirikan di atas tanah lunak, maka biasanya ada dua masalah geoteknik yang harus diselesaikan yaitu daya dukung yang rendah dan penurunan serta beda penurunan yang relatif besar. Walaupun pondasi dalam dapat mengatasi kedua masalah tersebut, penyelesaian ini menjadi tidak ekonomis bila konstruksi berdiri di atas daerah yang luas, misalnya : embankment jalan, landas pacu pesawat, kompleks perumahan, pabrik, tanki-tanki di kilang minyak, dan proyek reklamasi. Salah satu metode untuk mengatasi masalah tersebut adalah dengan menggunakan teknik prakompresi. Prakompresi adalah suatu proses pemampatan tanah pondasi dengan jalan pemberian pembebanan sementara (prabeban/preloading)sebelum konstruksi yang sesungguhnya didirikan. Proses konsolidasi akan semakin cepat terjadi dengan menggunakan metode prakompresi yang dikombinasikan dengan pemasangan Prefabricated Vertical Drain (PVD). Gambar 1 Pemasangan Prefabricated Vertical Drain (PVD)

This work reports on the growth and properties of Cathodic Arc Physical Vapor Deposition of low friction-coefficient CrCN coatings, as deposited on the basis of complementary carbon/nitrogen gradient concentrations through the film thickness. The coatings developed in this study exhibited friction coefficients ranging from 0.2 to 0.6, against 100Cr6 bearing steel, depending on the preparation conditions. Gradient CrCN films with

In the polymer electrolyte membrane fuel cells (PEMFCs), low corrosion resistance and high interfacial contact resistance (ICR) are two controversial issues in usage of AISI 316L stainless steel as a metallic bipolar plate. For solving these problems, investigation and development of different coatings and/or surface treatments are inevitable. Corrosion behavior and ICR of AISI 316L specimens coated with 1, 2, and 3 µm thick TiN were investigated. Potentiodynamic (PD), potentiostatic (PS) and electrochemical impedance spectroscopy (EIS) tests were conducted at 80 °C in a pH3 H 2 SO 4 +2 ppm HF solution purged with either O 2 or H 2 under both simulated cathodic and anodic conditions. The PS corrosion test results revealed that the current densities of the specimens were below 1 µA cm −2. In the simulated cathodic condition, an increase of coating thickness from 1 to 3 µm led to a relatively large decrease of the current density from 0.76 to 0.43 µA cm −2. Furthermore, the ICR values of the coated specimens after the PS test were lower than that of the uncoated specimen before the PS. In general, the TiN coating decreases the ICR, and has enough corrosion resistance in simulated PEMFC conditions. However, none of the coatings achieved the DOE ICR targets.

The main objective of this paper is to study the slurry erosion and corrosion behavior of WC10Co4Cr, Armcore 'M' Stellite 6 and 12 HVOF coatings, TiAlN PVD coating, selected steels, such as X20Cr13, 17Cr–4Ni pH steel and Ti6Al4V titanium alloy alongwith ...

In this paper, experimental investigations are carried out by end milling process on hardened tool steel, Impax Hi Hard (Hardness 55 HRC) a newly developed tool steel material used by tool and die making industries. Experiments are performed with an aim to study performance investigations of machining parameters such as cutting speed, feed, depth of cut and width of cut with consideration of multiple responses viz. volume of material removed, tool wear, tool life and surface finish to evaluate the performance of PVD coated carbide inserts and ball end mill cutters. It has been observed through scanning electron microscope, X-ray diffraction technique (EDX) that chipping and adhesion are active tool wear mechanisms and saw-toothed chips are formed while machining of Impax Hi Hard steel. It is also noticed out that tool life is not enhanced while machining with minimum quantity lubricant than dry machining. From the investigations, it is observed that hard machining can be considered as an alternative to grinding and EDM, traditional methods of machining difficult-to-machine materials i.e. hardened steel with hardness greater than 50 HRC with a scope of improved productivity, increased flexibility, decreased capital expenses and reduced environmental waste.

Two PVD coated powder metallurgy high speed steel (PM-HSS) gear cutters were investigated when machining helical gears made from AISI 19MnCr5 steel with hardness between 140 and 180 HV. Machining trials were carried out with gear cutters coated with TiAlN (nano layers) and TiN (mono layer). Crater and flank wears were measured and analysed after all the machining trials. Analyses of the worn tools show that the TiAlN coated gear cutter performed better than the TiN coated gear cutter. This can be attributed to its nano layers and the higher hardness of the TiAlN coating. The dominant tool wear mechanisms were adhesion, abrasion, delaminating of the coating layer and chipping of the cutting edge.

Titanium alloy (Ti-6Al-4V) can be economically machined with high-pressure coolant (HPC) supply. In this study, an artificial neural network (ANN) model was developed for the analysis and prediction of tool wear parameters when machining Ti-6Al-4V alloy with conventional flow and high-pressure coolant flow, up to 203 bar. Machining trials were conducted at different cutting conditions for both rough and finish turning operations with uncoated carbide (K10 grade) and double TiAlN/TiN, PVD coated carbide (K10 substrate) inserts. The cutting parameters (cutting speed, feed rate, depth of cut, coolant pressure, and tool type) and the process parameters (cutting forces, feed force, machined surface roughness, and circularity) were used as input data set to train the three-layered feed- forward, back-propagation artificial neural networks. The networks were trained to predict tool life and wear rate separately. The results show that the correlation coefficients between the neural network ...