bluuebunny/crossref_metadata_2025 huggingface dataset:
Industrial Aspects of Heat Treatment in a Glow Discharge System
Authors: Staines A. M. , Hart S.
Published: January 2014

Recent developments in plasma heat treatment equipment and processing techniques are reviewed. This process, which is now firmly established in the UK, is being used in a wide range of applications. Case histories are presented to illustrate some of the associated advantages and potential drawbacks. Temperature uniformity within the vacuum vessel is identified as the major problem when treating mixed workloads. Advances in the field of plasma carburising have led to improvements in the design of nitriding equipment and in particular to the development of pulse power supplies and additional heating systems. Equipment incorporating these features is claimed to give improved temperature uniformity throughout the workload. Plasma carburising equipment is now available and production facilities are operational in the USA, France, Japan, and the FRG. The current status of plasma carburising is assessed, and the areas which present problems are identified.
Reclamation by hardsurfacing
Authors: Cookson C. P.
Published: January 2014

The flexibility of the various hardfacing techniques in repairing or renovating components operating in severe wear environments can yield significant cost savings as well as providing performance that often exceeds the original design. In the following four case studies, Dr Clive Cookson, Chairman and Managing Director of Cookson Enterprises, illustrates the benefits that can accrue from weld reclamation in a wide range of industrial applications.
HARDFACING: IS A SECOND LAYER REALLY NECESSARY
Authors: Womersley D.
Published: January 2014

Dilution of a hardfacing alloy by the substrate can cause significant reductions in the hardness and wear resistance of the deposited coating. Application of a second layer of hardfacing alloy is one of many techniques used to minimise dilution. However, research into the hardfacing of grey cast iron by spraying and welding processes to resist abrasive wear has shown that, in general, no benefit is derived from the application of two layers rather than one layer of alloy: application of the second layer therefore appears to be economically unwarranted.
Plasma Arc Spraying of Ti-6Al-4V with Cu-Ni-In
Authors: Raz Y. , Dirnfeld S.
Published: January 2014

The influence of atmosphere, current, voltage, and powder feed rate on the microstructure of air plasma sprayed Cu-Ni-In coatings has been investigated. The effect of substrate pretreatment by blasting with alumina grit on substrate-coating bonding was also studied. Air blasting with alumina at appropriate pressures produced surface roughness that enhanced bonding by allowing particles of Cu-Ni-In powder contacting the substrate surface to bond by a combination of mechanical interlocking, solidification forces, diffusion, and micro welding. Blasting also caused alumina particles to become embedded in the surface, causing local contamination. A logarithmic relationship was found between the kinetic energy of microthe alumina particles and substrate weight loss during blasting. Substrate-coating lap shear bond strength was found to increase with increasing alumina particle size in the range studied (24-220 mesh) and to reach a maximum at the air pressure corresponding to maximal surface roughness. Spraying parameters found to give optimal microstructural properties and microstructures are given.
Evaluation of Corrosion Resistance of Metal Sprayed and Painted Steel
Authors: Kaneko Fujio , Nagasaka Hideo
Published: January 2014

The combined use of metal spraying and painting to enhance the corrosion resistance of steel has been studied. Zinc, aluminium, and 85 Zn-15 Al layers, ∼100 μm in thickness, were sprayed on to steel substrates. Chlorinated rubber, acrylic, and epoxy resin paints were then applied to a thickness of 50-100 μm on the metal sprayed layers. The corrosion resistance was assessed using an accelerated deterioration test in which test samples were exposed to cycles consisting of 1h UV irradiation at 40°C followed by immersion for 1h in 3%NaCI solution. Bending and salt spray tests were also conducted. Corrosion resistance was found not to depend on the bending angle of the testpieces, but only on the character of the sprayed metallic layers. However, the paint overcoats did show some cracking after bending, suggesting that salt spray testing after bending is an effective means of evaluating the comformability of sprayed metal and paint coatings. It is concluded that paint overcoats on sprayed metal layers improve the corrosion resistance of steel considerably.
Comparison of Laser Hardfacing with Conventional Processes
Authors: Monson P. J. E. , Steen W. M.
Published: January 2014

Nickel based and cobalt based hardfacing layers produced by laser and a variety of conventional welding and spraying processes have been compared. Parameters measured include dilution, distortion, microstructure, surface texture, wear resistance, and macro- and microhardness of the constituent phases. Laser processing was found to give the lowest variation in deposit thickness, together with a fusion bond of low dilution. The high cooling rates of laser deposits lead to finer structures, greater microhardness, and enhanced solid solubility (offering the opportunity of developing a new range of hardfacing alloys). Carbide and eutectic phases in the laser deposited layers were of constant composition, whereas the solid solution phase was the hardest obtained owing to the presence of higher concentrations of carbon and chromium. Abrasive wear tests in general showed improved properties with increasing carbide size, although the increased hardness of the laser layer solid solution phase was also of benefit. The cobalt based laser hardfaced layer showed the highest wear resistance.
Diffusion Chromising of Steel by Chemical Vapour Deposition Using Chloride Compounds: 2 Coating Structure
Authors: Jyrkäs K.
Published: January 2014

The surface structure and composition of coatings obtained by diffusion chromising has been investigated. The coatings were prepared by gas phase diffusion chromising using metallic chromium and iron(III)chloride as reagents. The average chromium content of the coating was determined by direct current plasma atomic emission spectrometry. The structure and composition of the coatings were investigated by electron microscopy, energy dispersive X-ray microanalysis, X-ray diffraction, glow discharge optical emission spectrometry, and X-ray photoelectron spectrometry. A diffusion coating with 50-55 wt-%Cr on the surface was obtained. The average chromium content of the coating was 20-30 wt-%. The coating layer was uniform with no boundary layer between base metal and coating. An oxide or hydroxide layer (20-50 nm thick) was found on the surface. Formation of a carbide (Cr23C6)layer was detected in some cases.
Formation of Titanium Nitride Layers and Composite Layers under Glow Discharge Conditions
Authors: Wierzchon T. , Michalski J.
Published: January 2014

By applying a glow discharge in a gaseous mixture composed of TiCI4, H2, and N2 it is possible to produce titanium nitride layers or – if the process is conducted in two stages differing in the atmospheres used – composite layers, e.g. a nitrided layer covered by a titanium nitride layer. Electric activation of the gaseous medium and of the surface under treatment makes it possible to reduce the treatment temperature to ∼600°C.An installation is described for producing titanium nitride layers and composite layers and the results of structural examinations and wear tests performed on these layers are presented.
Designing Advanced Coatings for Wear Protection
Authors: Holleck H.
Published: January 2014

Improved knowledge of the ways in which the structures, properties, and behaviour of coated materials are interrelated, as well as technical advances in the production of specific layers, constitutes a basis on which advanced coatings with improved properties and wear resistance can be realised. Many of the relations between constitution, microstructure, properties, and application behaviour, elaborated for bulk materials, can also be used to understand the behaviour of layer materials and to optimise coatings. After a survey and a classification of the most common protective layer materials, typical examples of advanced coating concepts with improved properties, including gradient layers, multicomponent mixed layers, metastable layer materials, multi/ayers, and multiphase layer materials, are discussed.
Effect of Coatings on Rolling Contact Fatigue Behaviour of MSO Bearing Steel
Authors: Middleton R. M. , Huang P. J. , Wells M. G. H. , Kant R. A.
Published: January 2014

There is a continuing requirement for improved bearing performance for both commercial and military applications. Service temperatures are increasing steadily due to increased power requirements and corrosion of components remains a major concern as well, particularly for bearings in military systems. In our ongoing study, a number of different coatings were applied to VIM–VAR M50 bearing steel to improve both corrosion resistance and rolling contact fatigue behaviour. This report deals with coatings from the ion beam assisted deposition (I BAD) of TiN, details of the coating process, and test results obtained. The rolling contact fatigue performance of IBAD TiN coated M50 samples, measured with a ball/rod tester at a contact Hertzian stress of 5420 MN m-2, is discussed. Preliminary data on corrosion properties are also presented.
Characterisation of Ti(C,N) and Tin Coatings on Powder Metallurgy High Speed Steels
Authors: Hedenqvist P. , Olsson M. , Hogmark S.
Published: January 2014

Titanium carbonitride and titanium nitride coatings deposited on two powder metallurgy high speed steels have been characterised with respect to their microstructure, residual stresses, thickness, and hardness. The adhesion between coatings and substrates has also been determined. Finally, the tribological performance of the coatings was studied using an erosive wear test. The results show that the Ti(C,N) coating on the ASP 60 substrate is not only the hardest and best adhering, but also the coating with the lowest erosion rate. It is concluded that in order to obtain a general characterisation of the tribological properties of a coated material a number of coating properties must be determined. The overall performance of a coated component depends on both substrate and coating materials as well as their compatibility, and in order to fully understand how the substrate material influences the coating properties, powerful analytical techniques such as analytical transmission electron microscopy must be used.
TiN Coatings for Protection Against Combined Wear and Oxidation
Authors: Rogers P. M. , Hutchings I. M. , Little J. A.
Published: January 2014

A method has been developed to study the behaviour of materials under conditions of simultaneous high temperature oxidation and mechanical wear by the action of abrasive particles in a jluidised bed. The possibility of using TiN coatings to provide a barrier to such an environment has been explored. The behaviour of steels coated with TiN by PVD was compared with that of the unprotected substrate materials. It wasfound that the TiN coating survived for a longer period at lower impact velocities of the bed particles. An increase in coating wastage rate with temperature between 200 and 400°C was suggested to be primarily due to a decrease in the coating hardness. A large reduction in the survival time of the coating above 400° C was believed to be due to the increase in the oxidation rate of TiN at these temperatures. Mechanisms of material removal were identified by SEM examination of worn specimen surfaces.
Sliding Wear of M50 and T1 High Speed Steels at Room and Elevated Temperatures
Authors: Ghomashchi M. R.
Published: January 2014

This paper examines the wear characteristics of M50 and T 1 high speed steels at temperatures up to 600° C by means of pin on disc wear tests. The mechanism is found to be one of severe oxidation wear for loads of 10-50 N; wear increasing with load applied. The T 1 steel showed superior wear resistance to M50 but was not wear resistant above 400° C and showed a very high wear rate at 600° C.
Application of laser textured dull steel to automobile panels
Authors: Ujihara Shin , Cooket D. W.
Published: January 2014

The advantages of surface engineering finish rolls used to produce automobile panels are described. By laser texturing the skin pass roll it is possible to obtain a more uniform surface finish on the steel strip and so a better final painted finish. The effect of surface finish on formability (drawability and antigalling behaviour) was also investigated. Practical aspects are discussed and the prospect of tailoring surface finish to produce sheet with optimised properties for specific applications is put forward.
Boronising Behaviour of Ni–Si–Cr Steel
Authors: Reddy A. V.
Published: January 2014

I sothermal and isochronal boronising experiments were carried out using a mixture consisting of 92%SiC, 5%B4C, and 3%KBF4 on Ni–Si–Cr steel. The boride surface, the interface, and the matrix were characterised by electron probe microanalysis, microstructural examination, X-ray diffraction, and microhardness measurements. In contrast to the reported literature, it was shown that the boronising behaviour of the Ni-Si-Cr steel was similar to that of many low alloy steels. It was further established that the interface layer was not ferrite, as reported for silicon rich steels, but was a borzde of the type Fe3(SiB).
αPhase in Plasma Nitrided Titanium Alloys: Preferred Orientation and Composition
Authors: Bacci T. , Scardi P. , Tesi B. , Gianogli C.
Published: January 2014

Conventional (wide angle) and advanced (microdiffractometry) X-ray diffraction techniques have been used to characterise plasma nitrided specimens of commercial α+β titanium alloys (Ti-4Al-2Mn, Ti-5Al-2Fe, Ti-6Al-4V) in order to study the α phase (interstitial solid solution of nitrogen in hcp titanium). The results show that the (J. phase crystals, when in direct contact with the δand/or 8 titanium nitrides that form the compound layer, present a preferred orientation with the {Oll} lattice planes orthogonal to the direction of nitrogen diffusion. At greater depths, however, this preferred orientation becomes less marked, and in the diffusion layer disappears completely. By measuring the variations in {Oll} and {002} interplanar spacing it has been possible to correlate the nitrogen content of the α phase with distance from the specimen surface.
Surface engineering for corrosion protection of underbonnet and underbody automotive components
Authors: Pearce C. D.
Published: January 2014

The coatings available to give corrosion protection to underbonnet and underbody automotive components are reviewed together with design and application considerations for optimising cost effectiveness. The recent toxicity and environmental requirements are discussed and a table given that assesses the attributes of possible coatings.
High Temperature Mechanical Properties of Physical Vapour Deposited Titanium Nitride
Authors: Bull S. J. , Rickerby D. S. , Knight J. C. , Page T. F.
Published: January 2014

There is a clear need to understand how the microstructure of a surface coating dictates its properties and how these microstructure-property relationships change as afunction of temperature. Both high temperature hardness and X-ray diffraction studies have been performed which show the importance of understanding the way the coating microstructure changes with temperature if its mechanical properties at these temperatures are to be explained. Residual stress, hardness, and lattice strain are reduced as the temperature increases and the changes are not reversible. These changes are discussed in light of the variations in coating microstructure.
Compound Layer Characteristics Resulting from Plasma Nitrocarburising in Atmospheres Containing Carbon Dioxide Gas Additions
Authors: Haruman E. , Bell T. , Sun Y.
Published: January 2014

Plasma ferritic nitrocarburising of iron-carbon alloys and low alloy steels has been performed at 570°C in atmospheres containing carbon dioxide gas additions. Variations in compound layer structure, thickness, porosity, and composition have been investigated. It has been found that the formation of a predominantly & phase compound layer structure is favoured by the use of high nitrogen atmospheres, and cementite formation isfound to be delayed by the presence of carbon dioxide in the system. Initiation of cementite is found to be strongly dependent on substrate composition, and the formation of this cementite phase is not necessarily via pore formation or a denitriding lnechanism, as is commonly found with gaseous nitrocarburising. The compound layer thickness was found to increase with increasing carbon dioxide content, except where the substrate contained carbides, when a continuous reduction in compound layer thickness was observed. Some degree of porosity in the & subregion may develop during plasma nitrocarburising with high nitrogen additions. The pores are of an intergranular type, and the pore walls can dissolve oxygen when in direct contact with an open atmosphere. Proper process control and the addition of carbon dioxide to the atmosphere results in a reasonably thick compound layer composed predominantly of & phase.
Microstructure and Properties of Electrodischarge Machined Surfaces
Authors: Tomlinson W. J. , Adkin J. R.
Published: January 2014

Ten materials with a wide range of microstructures and properties have been electrodischarge machined using copper and graphite electrodes with three pulse energies, and their machining rates, roughness, microstructure, micro hardness, cracking behaviour, and - for the white cast iron - dry sliding wear behaviour deternlined. Materials that are difficult to machine by conventional means (e.g. metal matrix composites, white cast iron, and high silicon cast iron) could be readily processed. Machining rates were approximately a linear function of the square root of pulse energy. A similar topography, which was difficult to quantify, was observed on all the materials. Surface roughness of the tool steel was a function of cube root of pulse energy. Hard surface layers occurred on the ferrous materials, but in some non-ferrous materials softening occurred. Extensive cracking occurred only in steels and cast irons containing a high concentration of chrOlnium. Electrodischarge machining increased the wear resistance of white cast iron fivefold.
Multilayer CVD Coatings of Tic+ Tin and their Effect on Cutting Tool Life
Authors: Porat R.
Published: January 2014

One of the most useful combinations for coating cutting tools is a triple layer of TiC + TiCN + TiN. This combination gives combined wear protection: TiC has good adhesive wear resistance which protects the cutting tool from flank wear and TiN confers diffusion wear resistance which protects the tool from crater wear. As the number of coating layers was increased, keeping the overall coating thickness constant, the tool life improved when machining steels; the efficiency of the machining process was also improved since the cutting speed could be increased. The life of coated cutting tools when machining steel at different cutting speeds is examined and cutting tools with multilayer and single layer coatings are compared. Comparison is also made between multilayer TiC + TiN and TiC +Al2O3 + TiN coating combinations under the same cutting conditions.
THERMOSTABILITY OF DIAMONDLIKE CARBON FILMS
Authors: Liu Z. T. , Xu N. K. , Geng D. s. , Zheng X. L.
Published: January 2014

The thermostability of diamond like carbon (DLC) films was investigated. The results show that the structure and electrical resistivity of DLC films show no appreciable change after annealing at up to 400°C. After annealing at temperatures higher than 400°C, the amorphous carbon crystallises and the resistivity greatly decreases owing to the dehydrogenation of the DLC film, followed by the precipitation of small graphite crystals. However, the hardness remains approximately constant after annealing at temperatures in the range 200–700° C. This may be attributed to the incompleteness of the crystallisation and the very fine graphite particles formed during annealing.
PROPERTY ASSESSMENT OF LASER SURFACE TREATED TITANIUM ALLOYS
Authors: Abboud J. H. , West D. R. F. , Hibberd R. H.
Published: January 2014

Laser treatments have been used to produce a series of surface layers containing up to ∼ 65 at.-%Al on a near α IMI685 titanium alloy substrate and a mixture of aluminium powder and silicon carbide was used to produce a surface composite layer based on titanium aluminides; also, silicon carbide particles have been incorporated into commercial purity titanium and a β Ti-15V-3Al-3Cr-3Sn alloy. Exploratory tests of oxidation and erosion resistance have shown the beneficial effect of surface alloying with aluminium and of ceramic particle injection. Microstructural observations have been made of samples fractured in bend tests.
SURFACE ENGINEERING: PROVING THE QUALITY
Authors: Hunter H. , Thomas A. , Pleavin F. I. , Hodgson S.
Published: January 2014

Surface engineering is an enabling technology which can provide specialist surface properties while preserving the important structural features of the substrate. It can also save energy, reduce wear and corrosion, and, importantly, conserve rare materials by localising specialist properties at the surface rather than their needing to obtain throughout the bulk. Despite these advantages, the technology remains underutilised, with uncertainties regarding treatment consistency and quality causing potential users to hesitate. The ultimate solution lies in a proper understanding of the surface engineering processes and the key parameters which dictate the surface properties they produce. It will be this rigorous quality assurance of the treatment or coating procedure which will ensure good quality. In the meantime, it remains necessary to inspect many treated components (quality control) to assess key properties such as adhesion, thickness, porosity, and hardness. Industrial requirements for quality control of surface engineering are reviewed and the strengths and weaknesses of a range of measurement procedures are considered. Three techniques are discussed in detail: X-ray fluorescence for assessing thickness; ultralow load hardness testing for characterising thin surface films; and scanning acoustic microscopy for investigating adhesion, porosity, and thickness, predominantly of sprayed coatings.
Component reclamation and repair
Authors: Cookson C. P.
Published: January 2014

Some further examples of reclamation and modification work carried out by selective electroplating and weld processing at Cookson Enterprises are detailed.
Subsequent sealing of thermally sprayed coatings to increase corrosion resistance
Authors: Lugscheider E. , Jakiel P. , Messerschmidt V. , Beckschulte G.
Published: January 2014

Sealants are frequently applied to close the porosity in thermally sprayed coatings in order to improve corrosion resistance and a physical model has been developed to describe the penetration of sealant into the capillary pore system. It is concluded that a liquid intended for use as a sealant should have low viscosity, high surface tension, and a high wetting capability. However, measurements of coating adhesion have shown that gas trapped at high pressure within the pores can lead to a reduction in substrate–coating bond strength. Polarisation curves were measured for sealed and unsealed atmospheric plasma sprayed (APS) and high velocity oxyfuel (HVOF) WC–Co–Cr coatings in acid and alkaline solutions. Sealing was found to reduce the corrosion current density, but the effect depended strongly on the coating phase composition and microstructure. The WC–Co–Cr HVOF coatings showed better resistance because the higher chromium concentration in the matrix phase permitted a passive oxide layer to form, whereas when spraying Al2O3–TiO2 ceramic coatings AP S was found to give higher corrosion resistance as a result of a higher proportion of amorphous phase.
Experimental study Development of diamond impregnated cultlng tools
Authors: Igharo M. , Russell J.
Published: January 2014

This report describes the investigations carried out to determine the performance of a range of diamond impreganted core drills on flint aggregate reinforced concrete. Five core drills of various sizes (10, 16, 25, 32, and 40 mm) containing 6·7 wt-% diamond grit were produced for the initial evaluation. Each drill was subjected to a series of drilling tests to ascertain tool life and free cutting characteristics. The results showed a significant correlation between cutting action and drill diameter. At the lower end of the size range (10–25 mm), acceptable penetration rates were achieved at the expense of tool life. As the drill size was increased, tool life improved. The 32 mm diameter sample displayed the best combination of drilling rate and tool life. Premature failure of the 40 mm bit occurred due to the development of wear flats on the tool surface. Analysis of the initial test results revealed that the tentatively selected diamond content of 6·7 wt-% was not the optimum proportion for all sizes. Further studies involving samples containing different concentrations were therefore undertaken. It was found that the effectiveness of the drills could be markedly improved by varying the diamond content according to tool dimension.
Production of friction surfaced components using steel metal matrix composites produced by Osprey process
Authors: Bedfordt G. M. , Sharp R. P. , Wilson B. J. , Elias L. G.
Published: January 2014

Steel matrix composites produced by the Osprey process have been hot worked to produce barstock for the friction surfacing process developed by Frictec. Examination of the friction surfaced components reveals that a complete transformation of the original composite microstructure has taken place, producing a high degree of ceramic particle refinement and redistribution in the steel matrix. Initial laboratory wear tests indicate a significant increase in wear life. Applications and future developments are discussed.
ENVIRONMENTAL ISSUES IN SURFACE ENGINEERING AND RElATED INDUSTRIAL SECTORS
Authors: Bell T. , Dearnley P. A.
Published: January 2014

The background, particularly in Europe, to the increasing importance of the environmental driver for technological change is examined and discussed. Ferritic nitrocarburising has been chosen as the vehicle for studying change in the surface engineering sector, not only because it is recognised as the most rapidly growing surface engineering technology, but also because changes over the past 25 years have been radical. Thesubstitution of molten cyanide salt bath technology by less toxic gaseous methods has required significant levels of research and technological development, but the new technology is now widely used by the manufacturing industry on a global basis. Recent work, reviewed in the paper, has shown that a move to the totally environmentally friendly plasma nitriding technology is considered to be essential in the long term.
MOLECULAR DYNAMICS SIMULATION OF ION ASSISTED DEPOSITION
Authors: Byeli A. V. , Fedotov S. A.
Published: January 2014

Ion plasma deposition with simultaneous ion bombardment is one of the most promising techniques to improve the structure and properties of coatings. These effects are strongly dependent on the ion irradiation characteristics (current density, energy, etc.). A program based on molecular dynamics simulation has been developed to model ion assisted deposition. The model predicts film surface smoothing, improvement of stoichiometry, and some other effects which are discussed and compared with the experimental data.
MICROSTRUCTURAL OBSERVATION OF M50 AND T1 HIGH SPEED STEELS DURING SLIDING WEAR
Authors: Ghomashchi M. R.
Published: January 2014

The sliding wear behaviour of M50 and Tl high speed steels was investigated using a pin on disc machine. The wear mechanism is one of severe oxidation wear and wear damage was more severe in M50 steel; this was attributed to its lower primary carbides content. The following factors improve the wear resistance of the steels: a higher percentage of primary carbide, a less dispersed carbide distribution, a simple carbide morphology, and smaller carbide paticles. Sliding wear tests were carried out on Tl steel at elevated temperaturesand more pronounced wear was observed: at 600°C it was catastrophic. At this temperature the debris became detached from the counterfaces with considerable ease.
TUNGSTEN THIN FILM DEPOSITION BY 5 μm MULTIPHOTON DISSOCIATION OF W(CO)6
Authors: Díaz L. , González-Díaz P. F. , Santos M. , Sigüenza c. , Trushin S. A.
Published: January 2014

Summed frequency radiation from two synchronised CO2 transversely excited atmospheric lasers in an AgGaSe2 crystal, with energies up to 50 mJ at frequencies of ∼2000 cm–1 has been used to study infrared multiple photon dissociation of W(CO)6 and to induce tungsten thin film deposition. The cross-section of multiphoton absorption saturates, but at a flux close to 40 mJ cm–2 is still high enough (2 x 10–17 cm2) to allow absorption, on average, of more than 20 photons per molecule, overcoming the dissociation threshold. In parallel beam configuration the multiphoton dissociation yield is proportional to the beam flux raised to the power 1·6 and the critical flux is ⋜120 mJ cm–2.Averaged energy absorbed per molecule at this flux, calculated on the basis of Judd s absorption law, overcomes total bond dissociation energy by only ∼ 1·4 eV. A transmission electron microscopy study of the deposited tungsten thin film shows that the film is amorphous and homogeneous with a grain size <1 nm.
Surface Modification Technologies VIII
Authors:   none
Published: January 2014

The beautiful and ancient city of Nice, located on the French Riviera, was certainly a splendid location for this conference which was sponsored by SF2M and TMS, reports Dr PETER DEARNLEY. The venue, the Acropolis Conference Centre, was shared with the IFHT who, by prior arrangement, had kindly agreed to allow SMT delegates to attend their sessions and to visit the heat treatment exhibition.
NEUTRON STRAIN SCANNING OF METAL COMPONENTS
Authors: Webster P. J. , Wang X. D.
Published: January 2014

The technique of neutron strain scanning is describedand its application to through surface measurement of the residual stress field of metal components is discussed.The technique is particularly suitable for non-destructive internal strain and stress mapping since the neutron is a relatively penetrating particle and measurements an be made, in principle, at any point in any orientation throughout a component, subject to neutronbeam attenuation and spatial resolution constraints. The technique is less well suited to measurements made olely in the outermost surface layers but may be used to obtain data through the surface into a component,provided instrumental surface effects are allowed for during data processing or are reduced to negligible values by instrument design and careful measuring procedures. Illustrative examples are given of experimentalresults obtained on a series of metal components, including autofrettaged tubes, new and used railway rails, and peened surfaces in which steep near surface stress gradients are observed.
MAPPING OF RESIDUAL STRESSES AROUND FASTENER HOLES IN HIGH STRENGTH ALUMINIUM ALLOY
Authors: Holdway P. , Cook R. , Bowen A. W.
Published: January 2014

Residual stress distributions around plain and cold expanded fastener holes in aluminium alloy 7050–T76 have been measured using the X-ray diffraction sin2Ψ method. Both radial and hoop stresses have been measured as a function of distance from the edge of the hole on the mandrel inlet and outlet faces. The effect of fatigue loading on the residual stress distribution around cold expanded holes has been investigated and is discussed in relation to measured fatigue endurance. The effect of the X-ray beam size on the resolution of the technique in the vicinity of the hole has been studied and life predictions incorporating the measured residual stresses have been correlated with fatigue endurance.
FORMATION AND MICROSTRUCTURE OF PlASMA SPRAYED POLYAMIDE COATINGS
Authors: Bao Y. , Gawne D. T. , Vesely D. , Bevis M. J.
Published: January 2014

The feasibility of plasma spray deposition of polyamide 11 on steel has been investigated. The conditions for he preparation of high integrity deposits have been established by the control of precursor powder injection,torch traverse speed, and arc power. The optimal deposition conditions are designed to produce complete particle melting in the plasma, extensive flow on impact, and minimal thermal degradation. The study of the deposited layers revealed a significant loss incrystallinity and the presence of a minor metastable phase as a result of rapid solidification. Under nonoptimal deposition, substantial thermal degradation occurred for which a chain scission mechanism is proposed. No oxidation of the polymer was detected even though spraying was carried out in air.
14th International Thermal Spraying Conference
Authors:   none
Published: January 2014

GERALD BELL previews this triennial conference – the major international event in the thermal spraying calendar – which is shortly to takeplace in Kobe.
DEVELOPMENT OF DIFFUSION COATING IN JAPAN AND FUTURE TRENDS
Authors: Ueda S. , Bell T.
Published: January 2014

The development of diffusion coating, also known as metallic cementation, in Japan is discussed and some recent trends identified. The aluminium diffusion coating process applied on an industrial basis in Japan, the Karoraizu process patented by Matsumoto in 1930, is quite distinct from the Calorizing process employed elsewhere.
SURFACE MODIFICATION OF POLYMERS BY LOW TEMPERATURE PlASMA TECHNIQUES
Authors: Wu Z. , Shi Y. , Xie H. , Chen Y. , Zhang J. , Xu J. , Chen H.
Published: January 2014

Surface modification of polymers has been investigated using low temperature plasma techniques such as plasma grafting and plasma immersion ion implantation. The polymers studied include polyethylene terephthalate tyre cord, silk fabrics, and polyimide films and the changes in molecular structure of the polymer surface were analysed with the aid of X-ray photoelectron spectroscopy and attenuated total reflection infrared spectroscopy.
Effect of metal vapour vacuum arc ion implantation of aluminium on sliding wear characteristics of Ti-6Al-4V
Authors: Cornelius R. , Samandi M. , Evans P. J.
Published: January 2014

The metal vapour vacuum arc ion source is introduced and its more important features and system characteristics are described. Specific reference is made to applications in the field of metallurgical surface treatment by metal ion implantation and some recent developments are reviewed. The effects of aluminium ion implantation (doses up to 1·3 × 1017 ions/cm2) onthe sliding wear properties of Ti-6Al-4 V forms the emphasis of the ensuing investigation. Damage induced in sliding wear tests was reduced by about 50% after aluminium implantation, owing to a higher surface hardness. Several techniques of surface analysis including glancing angle X-ray diffraction and glow discharge optical emission spectroscopy indicated that subsurface precipitates were primarily responsible for the observed wear mechanism. The strengthening of subsurface material delayed the onset of superficial plastic deformation and resulted in enhanced tribological properties.
Hard coatings for orthopedic implants
Authors: Dahm K. L. , Anderson I. A. , Dearnley P. A.
Published: January 2014

Total hip replacement (THR) surgery is currently a common and successful procedure, but THR implants sometimes fail because of aseptic loosening after relatively short periods of time. Observations from retrieved femoral and acetabular TH R components have shown that scoring of both bearing surfaces occurs; scoring of the metallic femoral head components is a result of abrasion by bone cement debris embedded in the ultrahigh molecular weight polyethylene (UHMWPE) acetabular cups. To reduce wear of these bearing surfaces the feasibility of applying titanium nitride (TiN) coatings to Ti–6Al–4 V femoral heads is being investigated. In vitro wear tests of TiN coated Ti–6Al–4V against UHMWPE and TiN coated Ti–6Al–4 V have been performed using a pin on disc wear testing device. Early results showed that the wear is different for each wear couple. The UHMWPE has been found to wear initially by removal of residual machining marks and then by removal of thin layers of polymer. Pins consisting of TiN coated Ti–6Al–4V run against UHMWPE discs had a thin polymer transfer film and were lightly scored. Untreated Ti–6Al–4 V pins under the same conditions also had a thin polymer transfer film, but were scored more severely and caused slightly more polymer wear than the TiN coated pins. When TiN coated Ti–6Al–4 V pins were tested against TiN coated Ti–6Al–4 V discs the character of wear differed. The predominant wear mechanism involved oxidation.
Fibre Optic Nd–YAG laser cladding of preplaced hastelloy C powder
Authors: Brandt M. , Scott D. A. , Yellup J. M.
Published: January 2014

A series of experiments has been carried out to investigate the fibre optic Nd–YAG laser cladding of C–Mn steel with preplaced Hastelloy C powder. The beam from a pulsed Nd–YAG laser, operating at an average output power of 300 Jt: was transmitted to the workpiece via a step index glass fibre of length 5 m and core diameter 600 μm. A range of laser pulse energies, durations, and repetition rates was investigated forseveral focal length positions to determine their effect on clad layer formation and integrity. It was found that, for a limited range of process parameters, metallurgically sound clad layers up to 500 μm thick could be formed with less than 10% dilution by the substrate.
Coating thickness distribution and morphology of pulsed current copper electrodeposits
Authors: Kalantary M. R. , Gabe D. R.
Published: January 2014

Coating thickness distribution, surface appearance, and grain size are known to be important factors in determining the effectiveness of coatings used in the production of printed circuit boards. Square wave unipolar pulse and bipolar pulse reverse current electroplating of copper using an acid copper electrolyte has been reported to provide a coating superior to that produced by dc under certain pulsing conditions. The present paper describes a systematic assessment of the properties of electrodeposited coatings produced under unipolar pulse and bipolar pulse reverse current plating conditions. Results show that the overall coating uniformity under pulsing conditions is better than that obtained using dc plating. The surface texture of the coatings is shown to be strongly dependent on the pulsing conditions and is especially affected by bipolar pulse reverse conditions.
16th Hungarian National Heat Treatment Conference
Authors:   none
Published: January 2014

The biennial Hungarian Heat Treatment Conference provided an important opportunity to meet specialists in the fields of surface engineering, heat treatment, and materials science, writes Dr ZOLTÁN KOLOZSVARY of Plasmaterm SA, Tigre-Mures, Romania.
Thick thermal barrier coatings for diesel engines
Authors: Kvernes I. , Lugscheidert E.
Published: January 2014

Application of thermal barrier coatings (TBCs) in diesel engines offers benefits through improved component lifetimes, better thermal efficiency, and lower environmental emissions. Work done in this area within COST 501 is summarised and proposals to improve coating quality through enhanced control of the plasma spraying process are put forward. The control system will use fuzzy logic to optimise spraying parameters forindividual components. Of great importance is the cooling profile undergone by the component after coating, which must be designed to provide residual strains that will enhance coating lifetime.
PLASMA NITROCARBURISING WITH NITROGEN, HYDROGEN, AND HYDROGEN SULPHIDE GAS MIXTURES
Authors: Ruset C. , Bloyce A. , Bell T.
Published: January 2014

When a sulphur bearing gas is added to the nitrogen– hydrogen atmosphere used in a plasma thermochemical treatment, a nitrocarburising process can be performed because of the contribution from the carbon in the steel. In the present work, H2S has been used to introduce sulphur species into the discharge atmosphere. The sulphur promotes the nucleation of the 8 phase. A compound layer of thickness 30–45 μm with a duplex structure can be produced by this procedure on plain carbon steel and low alloy steel substrates. The outer zone (10–12 μm) is pure ε phase and the innermost zone consists essentially of γ’ phase. The influence of the gas composition, temperature, and duration of the treatment on the microhardness profiles and thickness of the compound layer has been investigated. Wear tests, using a plain carbon steel substrate, revealed significantly better wear behaviour of the sulphur bearing nitrocarburised specimens, compared with materials treated by conventional plasma nitriding.
Optimisation of Continuous Plasma Nitride–Reactive Magnetron Deposition Process for Titanium Nitriding of M2 Steel
Authors: Kingdon R. J. , Critchlow G. W. , Teer D. G. , Hampshire J.
Published: January 2014

A number of M2 steel substrates have been nitrided in a capacitively coupled rf plasma and TiN coated via reactive magnetron sputtering in a continuous (two stage) process. Both nitrided only and fully processed substrates have been characterised by hardness and scratch adhesion testing, scanning electron microscopy,X-ray diffraction, surface profilometry, and Auger electron spectroscopy. Using these techniques to identify important parameters, optimisation of the process has been made possible to give increased hardness and adhesion.
LASER SURFACE ALLOYING OF AI–12Si
Authors: Tomlinson W. J. , Bransden A. S.
Published: January 2014

An Al–12Si alloy has been laser alloyed using premixed powders and a carbon dioxide laser. Tracks 6 mm wide were alloyed with various amounts of Si, Ni, Fe, Cu, Mn, Cr, Co, Mo, and Ti and assessed for integrity,uniformity, hardness, and response to age hardening. In general, above a certain concentration the tracks were smooth with high integrity. Alloys containing more than 30%Fe cracked, and Mo and Ti were difficult to melt. Aging at 150aC for 25 h produced a significant increase in the hardness of Cu, Mn, and Cr alloyed tracks. Coatings 18 mm wide were alloyed with a series of Al–Ni and Al–Fe compositions containing various amounts of Cu, Mn, and Cr. After aging, the coatings were characterised and their resistance to cavitation erosion and sliding wear was determined. Additions of Cu, Mn, and Cr considerably increased the hardness of the Ni based coatings. In general, thecoatings had excellent properties. The resistance to erosion was very high, the best coating having an erosion rate 0.03 times that of the Al–12Si base material. Many coatings had a wear rate down to 0.2 times that of Al–12Si, but in some cases the wear rate was increased.
MICROSTRUCTURE AND SLIDING WEAR PROPERTIES OF LASER CLAD TiN REINFORCED COMPOSITE COATING
Authors: Lei T. C. , Ouyang J. H. , Pei Y. T. , Zhou Y.
Published: January 2014

The microstructure and sliding wear properties of a laser clad TiN composite coating on steel 1045 have been investigated using scanning electron microscopy, electron probe microanalysis, X -ray diffraction, and energy dispersive X-ray analysis and a pin-ring dry sliding wear test machine. Excellent fusion bonding with low dilution and absence of cracks has been obtained under laser cladding conditions in which specific energy was in the range 5-20 kJ cm-2 and power density was in the range 3·5-5 kW cm-2. The clad layers have been characterised by metallurgical examination, which showed that the bonding zone, which is about 6 ¨m thick, is a γ nickel solid solution growing from the bottom of the molten pool with planar crystal morphology. Particles of TiN, γ nickel, and a fine eutectic of γ nickel and (Fe, Cr)23 C6 in the interdendritic regions have been observed and a large number of TiN particles with irregular shapes remained after laser cladding. Partial dissolution occurred on the edges of the original TiN particulates, growth in which during resolidification was found in the clad region. The TiN reinforced composite coating produced by laser cladding has also been shown to possess good wear resistance.
SURFACE ENGINEERING OF STEELS BY PLASMA IMMERSION ION IMPLANTATION AND RELATED INNOVATIVE TECHNIQUES
Authors: Chen Y. , Shi Y. , Xie H. , Wu Z. , Jiang X. , Bell T. , Dong H.
Published: January 2014

Surface engineering of steels has been carried out using plasma inlmersion ion implantation (PI3) and related innovative techniques including plasma immersion ion beam enhanced deposition (PIIBED) of titanium and plasma immersion ion beam mixing (PIIBM) of nitrogen and titanium. Auger concentration profiles indicate that PI3 of nitrogen produces a smooth implantation profile in the surface layer of the steel. The formation of a thin layer of TiN on the surface of the specimens treated by PIIBED of titanium and by PIIBM of nitrogen and titanium was confirmed by X-ray photoelectron spectroscopy. It has been demonstrated that the surface hardness and wear resistance of all the treated specimens were greatly improved.
CHEMICAL POTENTIALS AND ACTIVITIES OF NITROGEN AND CARBON IMPOSED BY GASEOUS NITRIDING AND CARBURISING ATMOSPHERES
Authors: Mittemeijer E.J. , Slycke J.T.
Published: January 2014

The nitrogen and carbon activities are the cardinal parameters for process control of nitriding, nitrocarburising, carburising, and carbonitriding. The essential elements of the thermodynamic background for the definition of the so called nitrogen and carbon activities in nitrided and carburised surface layers of iron based substrates are presented in a comparative manner. Choice of the distinct reference states is discussed in relation to the consequences for the interpretation of activities and equilibrium constants of the reactions. Practical examples are used to show how the nitrogen and carbon activities can be established; the activities can, for example, be used to determine the amounts of dissolved nitrogen and carbon. Also, knowledge of the nitrogen and carbon activities makes it possible to minimise and to control nitrogen gas pore formation and/or to avoid cementite formation in engineered surface layers.
FRICTION AND CORROSION RESISTANCE OF SPUlTER DEPOSITED SUPERSATURATED METASTABLE AI-Mo ALLOYS
Authors: Abu-Zeid O. A. , Bates R. I.
Published: January 2014

Two closed field unbalanced magnetrons with aluminium and molybdenum targets were used for the codeposition of Al-Mo coatings with different compositions. A pin on disc machine and a computer controlled potentiostat were used to evaluate the tribological and corrosion properties of the deposited alloys respectively. Results show that introducing molybdenum into aluminium coatings improves their poor tribological properties; Al-Mo coatings with different compositions showed low wear behaviour and for coatings with high molybdenum contents (> 80%) friction coefficients against steel as low as 0·18 were obtained. The addition of molybdenum to aluminium coatings reduced their tendency to corrode and corrosion current density in a marine environment.
Electric arc deposition of carbon steel coatings with improved mechanical properties
Authors: Zurecki Z. , Garg D. , Bowe D.
Published: January 2014

Carbon steel coatings can be employed for hardfacing mechanical components used in moderately aggressive wear environments, provided they are sufficiently hardened by retained carbon. However, when thermal spraying using compressed air as the atomising gas, properties of carbon steel coatings are degraded by carbon loss through oxidation and oxide inclusions. It is shown that the physical and mechanical properties of these coatings can be greatly improved by spraying with inexpensive nitrogen produced on site by pressure swing adsorption or membrane separation, without the cost penalties incurred when using pure nitrogen. In some circumstances, such coatings can be used to replace more expensive alloy hardfacing layers.