bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microstructural Evaluations of the Plasma Transferred Arc Coated Layers on the Hardness, Wear Resistance, and Corrosion for the Hardfacing of Ni- and Co-Based Alloys
Authors: Kim H.-J. , Kim Y.J. 
Published: May 2021

Abstract
Commercially available coating techniques such as "open arc" and "spray & fuse" methods were used to compare the microstructural development with the plasma transferred arc (PTA) coating process for the hardfacing of NiCrBSi and Stellite 6 alloys. Denser eutectic structure was observed in the case of PTA coated layers of the Stellite 6 alloys than those of open arc weld-surfacing process. The shape of both carbides and borides in the 16C alloy coated by PTA processing were also obtained to have coarse morphology of carbides and borides while the "spray & fused" layers show a needle shape with finer distributions. Possible thermal history during each coating process is discussed. Based on microstructural observation, the hardness, wear resistance, and corrosion behaviors are reported. As expected, the alloy properties are directly related to their constituents of microstructure.
Slurry and Dry Erosion of High Velocity Oxy-Fuel Thermal Sprayed Coatings
Authors: Arsenault B. , Legoux J.G. , Immarigeon J.P. , Parameswaran V.R. , Hawthorne H. 
Published: May 2021

Abstract
Improvement of the high velocity oxy-fuel deposition (HVOF) process in the last decade has led to coatings with significant improved microstructures for better protection against wear and corrosion. HVOF coatings of cermet and metallic materials provide protection against erosion and are therefore good alternatives to the use of high-priced material. This paper presents the results of a study undertaken within the core research program of the National Research Council of Canada technology group in surface engineering, "SURFTEC", in which the performance of ten HVOF erosion-resistant coatings were evaluated under both dry and slurry erosion. Ten different types of HVOF coatings were studied including: six grades of WC with either Co or a Ni based matrix, one grade of Cr3C2 in a Ni-Cr matrix, and three grades of metallic alloy: Ni alloy, Co alloy and a SS 316-L. Coatings performance was evaluated with respect to the volume ratio and composition of metallic binder in carbide coatings, type of carbide, coating microstructure, impinging angle and the size of the erodent particles. All coatings were produced using the HVOF IP5000 system controlled by the Hawcs-II controller. Slurry jet erosion tests were conducted using a 10 %w/w alumina particle/water slurry. Two alumina particle sizes, 320 and 80 grit (nominal grain diameters 35 μm and 200 μm, respectively) were used. The nominal impact velocity of the slurry was 15 m/s and the nozzle-specimen distance 100 mm. Dry erosion tests were conducted using 50 μm diameter alumina particles projected onto coated flat test coupons through a carbide nozzle of diameter 1.14mm with a particle velocity of 84 m/s at a feed rate of 2 ±1 g/min. let impingement angles of 90° and 20° were used for both dry and slurry erosion tests. The volume loss of material under various erosion conditions was related to the coating properties and microstructure. Results indicate that the coating behavior is dependent on the erodent particle size, the erosion impinging angle to some extent and for slurry erosion, to the corrosion resistance of the cermet matrix.
Development of an Electric Arc Sprayed Self Lubricating Coating
Authors: Llewellyn H. , Grant P.S. , Newbery A.P. , Jordan R.M. 
Published: May 2021

Abstract
Electric arc sprayed coatings with a disperse lubricating phase have potential for use in a variety of industrial applications as bearing materials including low friction coatings for drill string joints in the oil industry to reduce casing wear and lower drilling torque. This paper describes the optimisation of electric arc spray parameters for Fe-0.06wt.%C that will subsequently be used as a self-lubricating coating matrix. The effect of electric arc spray parameters on the microstructure of a Fe-0.06wt.%C matrix has been characterised in terms of deposition rate, temperature during manufacture, porosity and microhardness. It has been shown that the local coating temperature during directly affects the final coating porosity, grain size, grain morphology and microhardness. The most effective parameter in controlling coating temperature was the coating deposition rate. The Fe0.06wt.% C coating microstructure was primary equiaxed ferrite with a dispersion of spherodised Fe3C particles formed from the in-situ tempering of the as-sprayed martensite or bainite during spraying. A fuller analytical treatment of these phenomena is given elsewhere (13). Fe-0.06wt.%C powder particles microstructure was primarily bainitic or martensitic. A small number of Fe-0.06wt.%C powder particles showed a dendritic phase which has been proposed as retained austenite because of austenite stabilisation by fine grains and the N2 atmosphere, or an unidentified nitride layer.
Wear Properties of WC/Co Coatings with Plasma and High Velocity Oxyfuel Spraying
Authors: Akasawa T. , Ai K. 
Published: May 2021

Abstract
A tungsten carbide/cobalt hard coating was deposited on steel substrates using plasma-arc and high velocity oxyfuel flame (HVOF) spraying. The characteristics of the coatings made by the two spraying methods were evaluated under identical conditions. The microstructure and the chemical composition ofthe coatings were different depending on the powder heating temperature and the velocity of particles. The sliding wear properties of the coatings against hardened steel at high sliding speeds showed different tendencies from those at low speeds. The plasma sprayed coatings resulted in better abrasive wear properties than HVOF coatings did. Material removal by solid particle erosion depended on the striking angle of particles on the substrate surface but there are no clear differences in wear properties between the two coatings.
Modelling of Coating Thickness, Heat Transfer and Fluid Flow and Its Correlation with the TBC Microstructure for a Plasma Sprayed Gas Turbine Application
Authors: Nylen P. , Wigren J. , Pejryd L. , Hansson M.-O. 
Published: May 2021

Abstract
The plasma spray deposition of a zirconia thermal barrier coating (TBC) on a gas turbine component has been examined using analytical and experimental techniques. The coating thickness was simulated by the use of commercial off-line programming software. The impinging jet was modelled by means of a finite difference elliptic code using a simplified turbulence model. Powder particle velocity, temperature history and trajectory were calculated using a stochastic discrete particle model. The heat transfer and fluid flow model were then used to calculate transient coating and substrate temperatures using the finite element method. The predicted thickness, temperature and velocity of the particles and the coating temperatures were compared with these measurements and good correlations were obtained. The coating microstructure was evaluated by optical and scanning microscopy techniques. Special attention was paid to the crack structures within the top coating. Finally, the correlation between the modelled parameters and the deposit microstructure was studied.
Fe-Simulations of Temperature and Stress Field Distribution in Thermally Sprayed Coatings Due to Deposition Process
Authors: Lugscheider E. , Barimani C. , Eritt U. , Kuzmenkov A. 
Published: May 2021

Abstract
During the formation of coating systems we find strong temperature gradients within the coating-substrate system resulting in thermally induced stresses in the coating after the spraying process. The purpose of this investigation is to develop numerical tools which provide insight into the relationship between coating parameters and the thermomechanical response of the produced composite. Transient finite element modelling is applied to calculate temperature and stress histories in thermally sprayed coatings due to the deposition process. Two different models with different levels of complexity have been developed to investigate the spraying process on a macroscopic and on a microscopic scale. Experimental investigations of the temperature history during spraying in the substrate have been carried out to determine boundary conditions for the mathematical model and to enable a verification of the obtained results.
Flattening Mechanism in Thermal Sprayed Particle Impinging on Flat Substrate
Authors: Fukumoto M. , Huang Y. , Ohwatari M. 
Published: May 2021

Abstract
The transitional behavior of the splat pattern of Ni particles sprayed on a flat substrate was investigated. Based on Auger analysis and SEM observation, it was confirmed that the splashing was formed not by material flowing on the substrate surface from the impingement center to the periphery, but by jetting away from the central disk. Observations of etched splat surfaces revealed that the bottom portion of the central disk solidified rapidly after impingement, and it was also confirmed, based on the direction of the splash pattern, that the splashing was caused by stumbling due to some type of deterrent to liquid flow, such as poor wettability at the flow tip or initial rapid solidification of the splat. The drastic change of the splat pattern near the transition temperature seems to occur when the Weber number of the liquid flow coincides with some critical value.
Integrated Simulation of the Atmospheric Plasma Spraying Process
Authors: Kundas S. , Kuzmenkov A. , Lugscheider E. , Eritt U. 
Published: May 2021

Abstract
The main purpose of this work is the development of mathematical and computer models for the integrated simulation of all stages of the atmospheric plasma spraying process (APS) with temperature dependent thermophysical and mechanical properties of the used materials and gases and experimental verification of the simulated results. The following mathematical models of APS were created: particle heating and movement in the plasma jet; coating structure formation; heat transfer and residual stresses in the coating-substrate system. The computer realization of these models enables us to model all stages of APS (integrated or separately). Databases of coating, substrate and plasma-gas substances include the temperature dependent properties. The model of APS is divided in 3 parts, which are connected by continuous data interface. Two dimensional approximation of plasma-gas velocity and temperature in the free plasma jet was used for computation of particle velocity, trajectory and temperature. This information was created with a special Graphic program module and included in database. Computer experiments for plasma spraying of Ah03 and ZrO2+8%Y2O3 in Ar/H2 plasma were carried out. The experimental verification of developed models with High-Velocity-Pyrometry (HVP) and Laser-Doppler-Anemometry (LDA) have shown the satisfactory precision of simulated results.
In Situ Measurement Within Plasma-Sprayed Zirconia Coatings Under Industrial Conditions
Authors: Baradel N. , Bianchi L. , Blein F. , Freslon A. , Jeandin M. 
Published: May 2021

Abstract
The thermomechanical properties of plasma-sprayed deposits strongly depend on residual stress distribution. This latter is mainly attributed to the relative torch/substrate velocity as well as to the cooling system location and efficiency. The determining of both quenching and thermal stresses, which are generated respectively during spraying stage and cooling stage, is then required to improve coatings quality. A rather simple apparatus, which consists in monitoring the curvature of a beam substrate during the whole deposition process, has been developed to work under industrial conditions. It has been applied to partially stabilized zirconia coatings performed onto stainless steel and cast iron substrates. Spraying temperature and plasma gun velocity have been selected as relevant parameters for this study about stress generation and mechanical release. Finally, four point bend tests have been performed on deposited samples to measure coating mechanical properties and to evaluate damage level.
Fatigue Strength and Fracture Mechanism of Thermally Sprayed WC-Co Coating on a Medium Carbon Steel by HVOF
Authors: Tajiri T. , Sakoda N. , Watanabe S. , Amano J. 
Published: May 2021

Abstract
Fatigue strength and fracture mechanism of a medium carbon steel with HVOF thermally sprayed WC-Co coatings were investigated under rotating bending. Two types of commercially available WC-Co powders were used, which have similar total chemical composition with different manufacturing processes. The fatigue strengths of the specimens with thick coatings were lower than that with thinner ones. Especially, it was found that the fatigue strengths of the thick coating specimens decreased more greatly than that of the grit blasted ones. Also, the morphology of the fatigue crack depended on the type of powders and the thickness of the coating. Futhermore, an embedded Al2O3 grit and a crack generated during the grit blasting were found near the fatigue fracture origin of the coated substrate.
Standardization of Metallographic Practices for Thermally Sprayed Coatings in the Automotive Industry
Authors: Blann G.A. 
Published: May 2021

Abstract
Thermally-sprayed coatings are applied to various materials to provide protection for beat-loaded parts as well as corrosion and wear. They also serve as a thermal barrier to reduce metal substrate temperatures. Microstructural analysis is used to characterize the substrate, the coating, and the adherence of the coating to the substrate. Accurate evaluation or these coatings depends heavily upon the quality of the polished surface produced by metallographic preparation. A well-prepared surface must first be free of plucked material and have minimal relief between the hard and soft constituents. The entire surface must be flat to allow a clear view of the interface and any reaction products that might be present in the coating or the substrate. Furthermore, the finished polished specimen must be scratch-free and have no resolution destroying films or stains. Various metal and oxide coatings on ferrous substrate material are used to demonstrate the excellent microstructural detail that is revealed when correct polishing procedures are used. These special techniques successfully address the problems normally encountered when preparing hard, brittle coatings or softer metallic coatings and substrates. As a result, clear microstructures are revealed across the specimen surface and valuable information is obtained.
Study on the Spray Processes and Characteristics of Cr3C2/NiCr Coating
Authors: Liu M. , Wang D. , Wang J. , Dai M. , Zhou K. 
Published: May 2021

Abstract
HVOF and plasma spray processes were used to apply Cr3C2-NiCr coatings, which were then characterized by X-ray diffraction and various other tests. The results revealed that the HVOF coatings were more stable than their plasma-sprayed counterparts as well as harder, tougher, less porous, and more erosion resistant. The HVOF coatings have been successfully used in industry and have proven to be an acceptable alternative to electroplated chromium.
Improvement of Adhesion Strength and Formation of Veined Structure in Alumina Coating
Authors: Era H. , Otsubo F. , Kishitake K. 
Published: May 2021

Abstract
Alumina coatings plasma-sprayed on alumina substrate with metallic bond coating (50Ni-50Cr) and on metal (Ni) substrate have been investigated in terms of adhesion strength and a veined structure formed in alumina coating. The veined structure is formed to heal up cracks and pores in sprayed alumina and substrate alumina after heat-treatment in air. The veined structure consists of oxides of NiAl2O4 (spinel-type) and NiO (NaCl-type). This indicates that the metallic elements in the bond coating or the metallic substrate diffuse along the cracks and pores in alumina and react with alumina. The alumina coating with veined structure shows high strength due to the mechanical anchoring of veined oxide and chemical bonding.
In-Flight Particle Characteristics of Plasma-Sprayed Dense Yttria Stabilized Zirconia
Authors: Leblanc L. , Moreau C. 
Published: May 2021

Abstract
The influence of input spray parameters on the state of plasma-sprayed zirconia powder is studied. The particle temperature, velocity and diameter are measured using an integrated optical monitoring system. The monitoring system allows the investigation of the particles behavior in the spray jet. The collected information is correlated to coating characteristics such as deposition efficiency, microstructure and thermal diffusivity. Results show that, by monitoring the state of sprayed particles, a better understanding of the coating microstructure and properties can be achieved.
Effect of In-Flight Particle Characteristics on the Properties of Plasma Sprayed NiCrAlY & NiCoCrAlY
Authors: Pejryd L. , Wigren J. , Gougeon P. , Moreau C. 
Published: May 2021

Abstract
Plasma sprayed MCrAlY bondcoats play a major role in thermal barrier coatings. During service, oxide forms on both sides of the bond coat and must be minimized to prevent coating failures. Along with powder chemistry, coating microstructure significantly influences oxide growth. It is known that both coating microstructure and coating strength are strongly related to plasma spraying parameters. This present work examines the effect of inflight particle properties on the adhesion strength and microstructure of NiCrAlY and NiCoCrAlY bondcoats. The relation between particle velocity and temperature and coating properties is particularly important. Relatively small changes in spray parameters such as arc current and gas flows can have a major impact on sprayed particles and consequently coating microstructure. Through online control of particle states it is expected that the quality of plasma-sprayed MCrAlY coatings can be significantly improved.
Controls for Plasma Spraying Based on Plasma Jet Stability Analysis
Authors: Beall L. , Duan Z. , Schein J. , Heberlein J. , Stachowicz M. , Planche M.P. 
Published: May 2021

Abstract
Despite the fact that plasma spraying has been a widely used technology over the past three decades, industries using this technology still need higher quality products. Presently, only a small degree of process control is used in most plasma spraying systems. Improved process control should lead to more consistent results and higher quality products. We discuss a relatively simple control scheme consisting of a microphone as a primary sensor and a fuzzy logic look-up model indicating the condition of the anode. Selected frequency peaks in the power spectrum of the microphone signal are analyzed online, and the results are correlated with an average jet length obtained from a series of high speed images. The jet length, in turn, is correlated with coating characteristics. A simple feedback control system is proposed which will counteract the negative effects of an eroded anode on coating quality.
In-Situ Observation and Acoustic Emission (AE) Analysis of Microscopic Fracture Process of Thermal Spray Coatings
Authors: Akita K. , Zhang G. , Takahashi S. , Misawa H. , Tobe S. 
Published: May 2021

Abstract
Microscopic fracture mechanisms of thermal spray coatings under bending stress are investigated. Samples of thermally sprayed coatings were made using three distances. The sprayed powder was pure molybdenum. Vertical microcracks occur in lamellae and subsequently, these cracks join together and form vertical macrocracks in the samples sprayed with a short spraying distance. On the other hand, horizontal microcracks occur at the lamellae interfaces, and these cracks link together in the samples sprayed with a long spraying distance. These tendencies can be explained in terms of the hardness of the lamella and the bonding strength between each lamella. It is clarified that the bonding strength between each lamella corresponds to the applied strain at the point of rapid increase of the acoustic emission (AE) event. The amplitude and rate of AE beyond the point of rapid increase are high in the coatings which formed macrocracks. It is concluded that the coating which has high resistance to crack formation has a high point of AE increase, low AE amplitude and low AE increasing rate.
Evaluation of Adhesion and Properties of Sprayed Coating by Ultrasonic Testing Method
Authors: Suga Y. , Lian D. 
Published: May 2021

Abstract
This study evaluates a nondestructive method for determining the adhesion strength and porosity of thermally sprayed coatings. The method is based on ultrasonic surface echo measurements. Porosity is surmised by the impedance of the coating and adhesion by the transmission coefficient. Experimental results confirmed that the method is effective for its intended use.
QS-9000 – Using the Automotive Requirements to Improve Existing ISO 9000 Systems
Authors: Young J.F. 
Published: May 2021

Abstract
In this paper, we will discuss how to incorporate several of the QS-9000 quality system requirements into an existing ISO 9000 quality system. This expansion of the existing quality system will be cost effective and ensure that the continuous improvement program will meet its goals. The QS-9000 quality system was developed in 1994 by the "Big Three" automotive and truck producers in Detroit, Michigan. This document, originated in the United States, is based upon the International Standard: ISO 9001-94. It is mandatory that any supplier of goods and/or services to either Chrysler, Ford or General Motors must have their quality system registered to the QS-9000 standard. We believe that there can be benefits to non-automotive organizations if they will incorporate some of the QS-9000 clauses into their current ISO 9000 quality systems. We will discuss actual cases in the following areas: purchasing, safety, process control, training, business management and continuous improvement. We will show how these examples of quality system enhancement are both effective and efficient ways of driving cost reduction and process improvement programs. Cost of quality initiatives can be better managed.
Experimental Design Based on Mclean & Anderson Modeling Applied to the Prediction of Plasma Properties
Authors: Blein F. , Roussel E. , Freslon A. 
Published: May 2021

Abstract
This paper presents a method for optimizing plasma spraying parameters based on statistical analysis and related models. The models presented account for particle velocity and plasma mass enthalpy and make it possible to study the influence of plasma properties on the deposition process.
Effects of Powder Morphology on Pneumatic Feeding and Plasma Spray Deposition
Authors: Anderson I.E. , Sordelet D.J. , Besser M.F. , Terpstra R.L. 
Published: May 2021

Abstract
The demand for highly continuous thermal spray deposition processing to gain manufacturing efficiency and enhanced control of deposition microstructure has driven the search for powder feedstocks that exhibit uniform flow behavior in pneumatic feeding devices even at low carrier gas flow ratios. This paper compares the continuous powder feeding characteristics of one type of feeding device for two different powder alloys fabricated by a representative set of powder processing methods, including spray dried, fused (cast) and crushed, and inert gas atomized. Powders were fabricated by both commercial vendors and Ames Laboratory processing equipment. The powder mass flow rate was found to depend directly on the apparent density of a specific powder type instead of the dry powder flowability, as initially expected.