Thermal Spray Method Research Articles

ANALISIS KEKERASAN PADA REAR COVER TRANSMISION VOLVO A35E SETELAH PROSES REKONDISI MENGGUNAKAN METODE THERMAL SPRAY

Abstract: Hardness is one of the mechanical properties of a material. The hardness of a material must be known especially for materials which in its use will be suppressed and friction. To know the hardness value of the material then do hardness test by using tool of hardness tester. One method used to increase the hardness of the material is by thermal spray method. Thermal Spray is a coating technology of both metal and non-metal materials that dispray on the base with the intention of providing protection against wear or recondition of the application so that back to the original function and size. The objective of this research is to know the result of hardness of transmission rear cover of PT 2509 VOLVO A35E after reconditioning. This research was carried out in May until June 2016. The research took place at PT.Intraco Penta Pima Service located in Manggar area of Balikpapan, East Kalimantan. The research object focused on the housing rear cover transmission of PT 2509 VOLVO A35 E which has been reconditioned with thermal spray method. In thermal spray, the material may be a powder, wire or rod and inserted into the flame of a spray gun. After the analysis, it is concluded that the hardness that occurs after the thermal spray process has changed which is about 30.88 HR which previously was at 10.32 HR. Influence that occurs to the parent metal undergoing the process of reconditioning, which in the presence of the recondition process that occurs there will be a change in the nature of material hardness on the rear cover of 199%.

Sustainability of Metal Structures via Spray-Clad Remanufacturing

Structural reclamation and remanufacturing is an important future design consideration to allow sustainable recovery of degraded structural metals. Heavy machinery and infrastructure components subjected to extended use and/or environment induced degradation require costly and time-consuming replacement. If these parts can be remanufactured to original tolerances, and returned to service with “as good or better” performance, significant reductions in materials, cost, and environmental impact can be achieved. Localized additive restoration via thermal or cold spray methods is a promising approach in recovering and restoring original design strength of degraded metals. The advent of high velocity spray deposition technologies has allowed deposition of near full density materials. In this review, the fundamental scientific and technological elements of such local additive restoration is contemplated including materials, processes, and methodologies to assess the capabilities of such remanufactured systems. This points to sustainable material reclamation, as well as a route toward resource and process sustainability.

HVOF Sprayed WC Based Cermet Coating for Mitigation of Cavitation, Erosion & Abrasion in Hydro Turbine Blade

Considerable advancement has been made over the last decades in various thermal spray technologies, practices and applications. However, like other technologies, they have to continuously evolve to meet new troubles and industrial requirements. WC-based hard metals are widely used in industry mainly are being developed for a wide variety of applications to resist wear, erosion and cavitation due to their high hardness and toughness. Slurry erosion, abrasive wear andcavitation erosion problems are found in turbine runners as well as in other parts of the system. Slurry erosion complications are especially important during rainyPeriods in hydroelectric power plants owing the growth in the number of abrasive particles impacting the exteriors, especially in systems where the comprehensive clarification process is not possible. Portions in interaction with fluids usually needdistinctmaintenanceincluding time consuming heat treatments processing, welding, use of super alloy etc. Thermal spray coatings are appears as a practical alternative to the costly and health hazardous hard chrome plating to repair components and prevent excessive wear because during the deposition process no significant changes to the microstructure of substrates. The term thermal spray describes a family of processes that use chemical or electrical energy to melt (or soften) and accelerate particles of a material which is then deposited on a surface. HVOF sprayed cermet coatings have very low porosity, high hardness, high abrasive resistance, good wear resistance. The review presents the concerns related to materials and the fabrication process of protective wear resistant coatings by thermal spraying methods used for the protection of hydro turbine system.

Simple fabrication of rough halloysite nanotubes coatings by thermal spraying for high performance tumor cells capture

Here, we reported a fast, low-cost, and effective fabrication method of large-area and rough halloysite nanotubes (HNTs) coatings by thermal spraying of HNTs ethanol dispersions. A uniform HNTs coating with high transparence is achieved with tailorable surface roughness and thickness. Compared with normal cells, the tumor cells can be captured effectively with high capture yield by the HNTs coatings (expect HeLa cells), which is attributed to the enhanced topographic interactions between HNTs coating and cancer cells. HNTs coating formed from 2.5% ethanol dispersions shows the highest tumor cells capture yeild (90%), which is related to the appropriate roughness and anti-EpCAM conjugation. The capture yield of HNTs coating towards MCF-7 cells can be further improved to 93% within 2h under dynamic shear using a peristaltic pump. The capture yield increases with the incubation time, and the flow rate with 1.25mL/min leads to the maximum capture yield. The HNTs coatings are also effective for capture of tumor cells spiked in artificial blood samples and blood samples from patients with metastatic breast cancer. More than 90% targeted MCF-7 cells and very small amounts of white blood cells are captured by the anti-EpCAM conjugated HNTs coatings from a blood sample. HNTs are further loaded anticancer drug doxorubicin (DOX) and then thermally sprayed into coatings. The MCF-7 cells captured on DOX loaded HNTs coating display significant membrane rupture characteristic and only 3% cell viability after 16h. The high capture efficiency of tumor cells by HNTs coating fabricated by the thermal spraying method makes them show promising applications in clinical circulating tumor cells capture for early diagnosis and monitoring of cancer patients. The high killing ability of the DOX loaded HNTs coating can also be designed as an implantable therapeutic device for preventing tumor metastasis.

Analysis of the ceramic layer microstructure influence on plasma spray thermal barrier coating performance

This paper outlines the results of analysis and describes the structure of the thermal protection coatings formed by atomic ion stream deposition in vacuum, and plasma thermal spraying method. Crystallite structure features are considered along with the crystallite dimensions, spatial orientation, and position of the boundaries between separate crystallites. Discontinuity, volume, and morphology of the pores has been evaluated. Experimental studies have been accomplished using various fractions of the powder-like material ZrO2 – 8%Y2O3. The influence of the coating microstructure on the coating performance has been analyzed, such as adhesive strength, thermal stability, and thermal conductivity.

Wear and corrosion studies of Fe–B–Cr alloy coating on en 24 steel by HVOF thermal spray method

This work investigate the wear behavior of Fe–B–Cr coatings on medium carbon steel (EN24) substrate is used for several automotive parts. The high velocity oxy-fuel (HVOF) method was used to create the new crystalline coating of Fe–B–Cr (composition of 59%Fe–26%B–15%Cr in wt %) on a medium carbon steel substrate (AISI 4340). The characteristics of powder and coating are investigated using scanning electron microscopy (SEM) merged with energy dispersive spectroscopy (EDS), optical microscopy (OM) and thermogravmentric analysis (TGA) which were undertaken in the partial characterization of the coating. The phase contents of both powder and coatings were studied by X-ray diffraction (XRD). The coatings consist of melted and un-melted particles identified in the coatings. Moreover, oxides and micro-cracks were observed at the surface. The mechanical property of the coatings was characterized using a microhardness test. The hardness value increased three times more than the substrate. The coated surface showed lower levels of porosity. Moreover, the electrochemical investigation found Fe–B–Cr coating on medium carbon steel. The corrosion test was carried out in an environment with 0.5 M of NaCl, which showed that the corrosion resistance improved by coating.

Overview on Recent Developments of Bondcoats for Plasma-Sprayed Thermal Barrier Coatings

The performance of MCrAlY (M = Ni, Co) bondcoats for atmospheric plasma-sprayed thermal barrier coatings (APS-TBCs) is substantially affected by the contents of Co, Ni, Cr, and Al as well as minor additions of Y, Hf, Zr, etc., but also by manufacturing-related properties such as coating thickness, porosity, surface roughness, and oxygen content. The latter properties depend in turn on the exact technology and set of parameters used for bondcoat deposition. The well-established LPPS process competes nowadays with alternative technologies such as HVOF and APS. In addition, new technologies have been developed for bondcoats manufacturing such as high-velocity APS or a combination of HVOF and APS for application of a flashcoat. Future developments of the bondcoat systems will likely include optimization of thermal spraying methods for obtaining complex bondcoat roughness profiles required for extended APS-TBC lifetimes. Introduction of the newest generation single-crystal superalloys possessing low Cr and high Al and refractory metals (Re, Ru) contents will require definition of new bondcoat compositions and/or multilayered bondcoats to minimize interdiffusion issues. The developments of new bondcoat compositions may be substantially facilitated using thermodynamic–kinetic modeling, the vast potential of which has been demonstrated in recent years.

Study on the Shielding Effectiveness of an Arc Thermal Metal Spraying Method against an Electromagnetic Pulse.

An electromagnetic pulse (EMP) explodes in real-time and causes critical damage within a short period to not only electric devices, but also to national infrastructures. In terms of EMP shielding rooms, metal plate has been used due to its excellent shielding effectiveness (SE). However, it has difficulties in manufacturing, as the fabrication of welded parts of metal plates and the cost of construction are non-economical. The objective of this study is to examine the applicability of the arc thermal metal spraying (ATMS) method as a new EMP shielding method to replace metal plate. The experimental parameters, metal types (Cu, Zn-Al), and coating thickness (100–700 μm) used for the ATMS method were considered. As an experiment, a SE test against an EMP in the range of 103 to 1010 Hz was conducted. Results showed that the ATMS coating with Zn-Al had similar shielding performance in comparison with metal plate. In conclusion, the ATMS method is judged to have a high possibility of actual application as a new EMP shielding material.

Lead-Free Piezoelectric Ceramic Coatings Fabricated by Thermal Spray Process.

This paper starts from a review on the progress in fabrication of piezoelectric ceramic coatings by thermal spray method. For our experimental work, two types of lead-free piezoelectric ceramic coatings, including potassium-sodium niobate-based and bismuth sodium titanate-based, are fabricated by thermal spray process, and their structure, morphology, and piezoelectric properties are characterized. Our obtained lead-free ceramic coatings exhibit single phase of perovskite structure, relatively dense morphology, and competitive piezoelectric coefficients. The mechanism of forming the piezoelectric perovskite crystalline phase by thermal spray involving melting-recrystallization process is analyzed in comparison to that of ceramic synthesis through solid-state reaction. Suppression of volatile loss and decomposition at high temperature due to the extremely high melting and cooling rate in the thermal spray process, and the impact on the resulting structure are discussed. Significant advantages of the thermal spray method over alternative processing methods for forming piezoelectric ceramic coatings are summarized. The combination of environmentally friendly lead-free compositions and the scalable thermal spray processing method will promote more applications of piezoelectric ceramic coatings for producing distributive sensors and transducers, and forming advanced smart structures and systems.

MAX-phase coatings produced by thermal spraying

This paper presents a comparative study on the Ti2AlC coatings produced by different thermal spray methods, as Ti2AlC is one of the most studied materials from the MAX-phase family. Microstructural ...

A model for determination of residual stresses in plasma coatings

The main reasons for the formation of residual (internal tensile) stresses in thermal spraying methods are the large differences in the temperatures of particles of deposited material on the surface of the substrate, the specific volumes of these particles at the moment of contact with the substrate and in the cooled condition, and also the non-uniformity of the distribution of temperature over the cross-section of the coating. The theory of hereditary elasticity is used to develop a mathematical model of theoretical justification of the process of formation and redistribution of the residual stresses which takes into account the relationship between the stresses and strains in the contact – substrate zone in heating and also the changes of their strength properties. Analytical dependences of controlling the technological parameters, such as the time and heating temperature, are proposed.

The Formation of Surface Roughness of Piston Rings for the Purpose of Improving the Adhesion of Wear-Resistant Coatings

The paper considers the application of wear resistant coatings by methods of gas thermal and flame spraying. It demonstrates the relationship between adhesion strength of the sprayed coating and surface roughness after abrasive jet machining using piston rings with steel-molybdenum coating as an example. The authors consider the results of studies aimed defining the relationship between surface roughness and of jet-abrasive machining conditions: the distance between the nozzle exit and the workpiece, the number of passages, the operating air pressure and frequency of the shot swapping.

Microstructural Effects and Properties of Non-line-of-Sight Coating Processing via Plasma Spray-Physical Vapor Deposition

Plasma spray-physical vapor deposition (PS-PVD) is a unique processing method that bridges the gap between conventional thermal spray and vapor phase methods, and enables highly tailorable coatings composed of a variety of materials in thin, dense layers or columnar microstructures with modification of the processing conditions. The strengths of this processing technique are material and microstructural flexibility, deposition speed, and potential for non-line-of-sight (NLOS) capability by vaporization of the feedstock material. The NLOS capability of PS-PVD is investigated here using yttria-stabilized zirconia and gadolinium zirconate, which are materials of interest for turbine engine applications. PS-PVD coatings were applied to static cylindrical substrates approximately 6-19 mm in diameter to study the coating morphology as a function of angle. In addition, coatings were deposited on flat substrates under various impingement configurations. Impingement angle had significant effects on the deposition mode, and microscopy of coatings indicated that there was a shift in the deposition mode at approximately 90° from incidence on the cylindrical samples, which may indicate the onset of more turbulent flow and PVD-like growth. Coatings deposited at non-perpendicular angles exhibited a higher density and nearly a 2× improvement in erosion performance when compared to coatings deposited with the torch normal to the surface.

Properties of titanium coating deposited using spheroidal powders by cold spraying

Purpose: TThe purpose of this study was to investigate the microstructure and the properties of the Ti coatings cold sprayed using spheroidal powder on the Al 7075 alloy. Design/methodology/approach: The Ni powder with irregular shape of grains was applied in the cold spraying process. The coatings were sprayed by means of a Impact Innovations 5/8 system with of nitrogen as process gas. Findings: The high kinetic energy of titanium particles causes their significant deformation and splats strongly adhere to the substrate and to each other. Cold sprayed titanium coatings exhibit negligible porosity and different mechanical properties caused by varying deformation degree of titanium powder. There were no phase changes in titanium powder during the spray process, and the coating consist of crystalline titanium. Practical implications: Titanium and its alloys have unique properties such as a high strength to weight ratio, excellent corrosion resistance and bio-compatibility. These features make it a material that is ideally suited for use in the aerospace, medical, and corrosive industries. Originality/value: The main advantage of cold spraying is elimination of influence of temperature on the particles of the coating material and the substrate that occurs in conventional thermal spraying methods. Therefore, the properties of such formed coatings are not available in other technologies.

13th International Conference on Films and Coatings

13th International Conference on Films and Coatings

Microstructure and Adhesion Properties Post-Annealed Metallic Coating of Fecrbmnsi on Tube and Internal Structure Coal-Fired Boiler

Iron-chrome based metallic coating is generally used to increase the life-time tube and internal structure of coal-fired boiler. The most common method used is thermal spray coating. The advantages of this method are simple in application, repair, and low cost. The post-heat treatment coating on metallic coating applied by the thermal spray method can affect to adhesion properties, the number of porosity and microstructure of coating material. The objective of this study is to analyze the influence of post-annealing on the metallic coating FeCrBMnSi applied by Twin Wire Arc-Spraying (TWAS) method on microstructure and adhesion properties which is applied on tube and internal structure of coal-fired boiler. Post-annealing was performed after coating application in vacuum furnace with variety of temperature at 500 o C, 600 o C and 700 o and holding time about 3 hours. Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray Spectroscopy (EDS) were used to analyze the morphology of microstructure, the uniformity of the deposit layer, and the percentage of porosity. X- Ray Diffraction (XRD) was used to determine phase formation and composition phase. Then, Pull Off Test was performed for adhesion test that is referred to ASTM D4541. The results shows that increasing post-annealed temperature cause microstructure of coating more crystalline, percentage of porosity decreased from 3% As-sprayed to 1,4% at 700 o C post-annealing temperature and it has an effect on the adhesion properties of coating which increase up to 25%.

Structure of the hydroxyapatite plasma-sprayed coatings deposited on pre-heated titanium substrates

Abstract Plasma spraying is the most commonly used thermal spray method for the application of hydroxyapatite (HA, Ca 10 (PO 4 ) 6 (OH) 2 ) coatings. In the present study, the HA coatings were plasma spraying deposited onto plates of titanium pre-heated to 20 °C, 300 °C and 550 °C. The obtained HA coatings were investigated by means of X-ray diffraction and scanning electron microscopy. It is found that the coatings, in addition to HA, contain the tetracalcium phosphate (TTCP, (Ca 4 (PO 4 ) 2 O) phase (~10%) and a small amount of CaO ( c- axes of the crystals parallel to the normal of plane coating n. The heating of substrate has a marked effect on the ultrastructure of coatings: the domain size increases from 790 to 1100 A, the strain Δ decreases from 1.6·10 -3 to 1,2·10 –3 , TTCP content diminishes from 12% to 7%. These results show that the effects due to heating of the substrate may be associated with partial recovery of HA microstructure.

Effect of precursor solutions on ZnO film via solution precursor plasma spray and corresponding gas sensing performances

Solution precursor plasma spraying (SPPS) as a novel thermal spray method was employed to deposit nano-structured ZnO thin film using different formulations of the precursor solution. This article focuses on the influence of the solution composition on the preferential orientation of crystal growth, on crystal size and surface morphology of the resulting ZnO films. The trend of preferential growth along (002) lattice plane of ZnO film was studied by slow scanning X-ray diffraction using a specific coefficient P(002). It appears that the thermal spray process promotes the buildup of ZnO films preferentially oriented along the c-axis. The shape of single particle tends to change from round shaped beads to hexagonal plates by increasing the volume ratio of ethanol in the solvent. Both cauliflower and honeycomb-like surface morphologies featuring high specific surface area and roughness were obtained through the SPPS process by varying solution composition. These ZnO films are hydrophobic with contact angle as high as 136°, which is seemingly associated with micro reliefs developing high surface specific area. Then the gas sensing performances of ZnO films preferentially oriented along (002) face were tentatively predicted using the “first principle calculation method” and were compared with those of conventional films that are mainly oriented along the (101) face. The (002) face displays better hydrogen adsorption capability than the (101) face with much larger resulting changes in electrical resistance. In conclusion, the c-axis oriented ZnO films obtained through SSPS have favorable performances to be used as sensitive layer in gas sensing applications.

The Influence of Particles Size and Composition Variation of NiCr-CrC(20NiCr) Metal Matrix Composites Coatings Properties on Boiler Tubes Application

Deposition of NiCr-CrC(20NiCr) metal matrix composite (MMCs) coating have been applied on the substrate of boiler tubes material with High Velocity Oxygen Fuel (HVOF) thermal spray method and constant parameter. Variation of particle size and composition on MMCs was conducted to determined the optimum conditions for boiler applications. Microvickers hardness, metallography and thermal shock resistance testing were investigated. The best performance for boiler tubes application is MMC NiCr-CrC(20NiCr) with 270 mesh of NiCr particles size and 60:40 of composition as evidence by the highest of hardness value (410 Hv) and slightly of discoloration after thermal shock resistance with two variation cooling medium. While at MMC NiCr-CrC(20NiCr) with 70:30 variation composition, coating hardness value will decrease in line with the smaller of particle size of NiCr.

Investigation of Isothermal Oxidation Behavior of Thermal Barrier Coatings (TBCs) Consisting of YSZ and Multilayered YSZ/Gd2Zr2O7 Ceramic Layers

Rare-earth zirconates have a big potential as top coat material of TBCs due to their superior high-temperature properties. TBCs are usually produced by thermal spray methods or electron beam physical vapor deposition (EB-PVD) techniques. Cold gas dynamic spray (CGDS) is a promising deposition method for production of dense and non-oxide bond coat compared to other thermal spray processes, while EB-PVD process provides good adhesion and strain tolerance for top coating layers of TBCs. In this study, in order to observe the effect of Gd2Zr2O7 on the oxidation behavior of TBCs, CoNiCrAlY was sprayed on substrate material using the CGDS method, afterward, yttria-stabilized zirconia (YSZ) and YSZ/Gd2Zr2O7 were deposited using EB-PVD technique. After deposition, specimens were isothermally oxidized in a high-temperature furnace at 1100 °C for 8, 24, 50, and 100 h. Microstructures of oxidized samples were examined and thermally grown oxide layer of TBCs were comparatively evaluated.