Dense titanium coatings by modified HVOF spraying

Kawakita, Jin; Katayama, Seiji; Fukushima, Takeshi; Katanoda, Hiroshi; Matsuo, Kazuyasu; Fukanuma, Hirotaka

doi:10.1016/j.surfcoat.2006.01.056

Cited by 102 publications

(45 citation statements)

References 6 publications

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“…By its higher particle temperature in comparison to CS, warm-sprayed particles are more softened upon impact, thus resulting in greater deformation facilitating the occurrence of adiabatic shear instability for bonding. The main advantage of WS is that many powder materials can be deposited in thermally softened state at high impact velocity, which allows to form dense coatings of materials such as Ti (Ref 17,(20)(21)(22) Since Ti-6Al-4V retains its high yield strength even in high temperatures up to 700 K (Ref 25), it is difficult to produce dense coating. There have been several efforts to produce Ti-6Al-4V coatings using CS (Ref 3,26,27).…”

Section: Introductionmentioning

confidence: 99%

Warm Spray Forming of Ti-6Al-4V

et al. 2013

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Warm spray (WS) is a modification of high-velocity oxy-fuel spraying, in which the temperature of the supersonic gas flow generated by the combustion of kerosene and oxygen is controlled by diluting the combustion flame with an inert gas such as nitrogen. The inert gas is injected into the mixing chamber placed between the combustion chamber and the powder feed ports, thus the temperature of the propellant gas can be controlled from~700 to 2,000 K. Since WS allows for higher particle temperatures in comparison to cold spray, warm sprayed particles are more softened upon impact, thus resulting in greater deformation facilitating the formation of shear instability for bonding. Recently, the combustion pressure of WS has been increased from 1 (low-pressure warm spray) to 4 MPa (high-pressure warm spray) in order to increase the velocity of sprayed particles. Effects of spray parameters on microstructure, mechanical properties, and splats formation of Ti-6Al-4V were systematically studied. Obtained coatings were examined by analyzing the coating cross-section images, microhardness as well as oxygen content. In addition, flattening ratio of splats was calculated as a function of nitrogen flow rate. It was found that the increased particle velocity caused by the increased combustion pressure had significant beneficial effects in terms of improving density and controlling the oxygen level in the sprayed Ti-6Al-4V coatings.

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Section: Introductionmentioning

confidence: 99%

Warm Spray Forming of Ti-6Al-4V

et al. 2013

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“…36) Also in the case of corrosion resistant coating, corrosion tends to happen through such particle boundaries where there are usually open pores. 37,38) Thus, it is quite important and meaningful to know particle boundaries in a coating layer. However, the cross section of a coating layer prepared by conventional metallographic polishing of WC-Co coatings which are composed of hard ceramics and relatively soft metal might be strongly modified by artifacts such as exaggerated pores due to pull-outs of ceramic particles and plastic deformation of metal during grinding and polishing.…”

Section: Comparison Of Microstructures Of Wc-co Coatingsmentioning

confidence: 99%

Observation of High Resolution Microstructures in Thermal Sprayed Coatings and Single Deposited Splats Using Ion Beam Milling

et al. 2011

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We have investigated microstructures of thermal sprayed coatings and single deposited splats using two types of ion beam milling: one is broad argon ion beam for the cross-sectioning of thermal sprayed coatings in a cross section polisher and the other is focused gallium ion beam for the cross-sectioning and transmission electron microscopy (TEM) sample preparation of single splats. The cross section of tungsten carbidecobalt (WC-Co) coatings fabricated by the polisher showed that it created a mirrored surface with minimized artifacts such as pull-outs of ceramic particles or smearings of pores which can be made by conventional metallographic preparations. A thin and locally re-thinned membrane of single nickel (Ni) splat was feasible to observe the internal interface of particle/substrate in high resolution atomic scale images. Substrate was heavily deformed by the impact of nickel particle with high kinetic and thermal energies. The particle and the substrate were intimately bonded without any voids or gaps.

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“…Due to unique properties of titanium the titanium based coatings are commonly used in aircraft, pipes for power plants, armour plating, naval ships, spacecraft and missiles [2]. At present the titanium coatings are produced by thermal spray methods such as air plasma spraying (APS) [3], chemical vapour deposition (CVD) [4], high velocity oxy-fuel (HVOF) [5], cold-sprayed [6], warm spray [7] and others. The critical velocity necessary to form the bonding of powder and substrate is relatively high for titanium due to its lower deformability related to its hcp crystal structure [8]; the reported microstructures of titanium coating tend to be porous as compared to more easily sprayable materials such as copper and aluminium.…”

Section: Introductionmentioning

confidence: 99%

Deposition and Characterization of the Titanium-Based Coating by a Multi-Chamber Detonation Sprayer

Arseenko

Tyurin

Prozorova

et al. 2015

MATEC Web of Conferences

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Abstract. This work introduces some of the aspects of the deposition of titanium-based coating (80-120 Pm thick) on aluminium samples using a multi-chamber detonation sprayer (MCDS). The characteristic feature of MCDS is that the powder is accelerated by using combustion products that are formed in MCDS chambers and are converged before entering the nozzle, where they interact with the two-phase gas-powder cloud. The microstructures and properties of the coating were characterized with the use of scanning electronic microscopes (SEM), optical microscope (OM), Xray Diffraction (XRD) techniques, and Vickers hardness tester with a 50 g test load. Wear tests were carried out using a computer controlled pin-on-disc type tribometer. It was established that MCDS has provided the conditions for formation of a dense titanium-based coating with a porosity of less than 1.0%, microhardness 810±250 HV0.05 and a specific wear rate of 2.077Â10-4 mm3(mÂ1 -1.

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Dense titanium coatings by modified HVOF spraying

Cited by 102 publications

References 6 publications

Warm Spray Forming of Ti-6Al-4V

Warm Spray Forming of Ti-6Al-4V

Observation of High Resolution Microstructures in Thermal Sprayed Coatings and Single Deposited Splats Using Ion Beam Milling

Deposition and Characterization of the Titanium-Based Coating by a Multi-Chamber Detonation Sprayer

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