https://bura.brunel.ac.uk/bitstream/2438/13101/1/FullText.pdf

Cold spraying - A materials perspective

Cold spraying (CS) has been widely explored over the last decade due to its low process temperature and limited thermal effect on spray materials. As a solid-state process, the inherent deficiencie...

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A Review of Advanced Composite and Nanostructured Coatings by Solid-State Cold Spraying Process

A facile and environment-friendly strategy is proposed to prepare dense, thin and antioxidant aluminum coatings on LA43M magnesium alloy via cold spraying and subsequent shot peening technologies. High-energy martensitic stainless steel particles are used to tamp the cold-sprayed coatings, which resulted in complete plastic deformation of Al particles and elimination of pores. The samples with shot-peened Al coating showed excellent corrosion resistance in electrochemical tests. Moreover, long-term salt spray and immersion test revealed that the shot-peened Al coating can effectively protect LA43M alloy from corrosion. Shot-peened Al coating offered promising and long term applications time in the harsh environment.

Enhanced corrosion resistance of cold-sprayed and shot-peened aluminum coatings on LA43M magnesium alloy

The cold spray technique was employed in this study to produce pure nickel (Ni) and nickel-Inconel 718 powder deposits on duplex stainless steel substrates. High quality coatings were manufactured using nitrogen as the propellant gas. The coatings exhibited satisfactory Inconel 718 (In718) retention within the Ni matrix due to the highly ductile binder phase necessary for fabrication. The characterization of the coating microstructures was implemented by means of X-ray diffraction, electron microscopy, energy-dispersive X-ray spectroscopy, and microhardness testing. In addition, the erosion resistance of both coatings was evaluated by performing cavitation erosion tests, with the analysis of the eroded surfaces revealing different erosion mechanisms for each coating. The results demonstrated the efficiency of the cold spray technique for use in the production of metal-metal matrix composite coatings and the potential of In718 use in applications which demand enhanced cavitation erosion resistance.

Microstructure and cavitation erosion performance of nickel-Inconel 718 composite coatings produced with cold spray

Since cold spray is widely considered as an additive manufacturing and damage repair technology, it is crucial to understand the coating build-up process and the temperature evolution. In this work, a 3D numerical model was developed to simulate the transient coating build-up process as well as the heat transfer in cold spray. By coupling the heat transfer with the ALE (Arbitrary Lagrangian–Eulerian) moving mesh and coating thickness model, this 3D model is able to investigate the temperature evolution of a coating which simultaneously grows according to the nozzle trajectory. The nozzle trajectory that represents the heat source and mass flux of particle impact is generated and simulated in the offline programming software RobotStudio™. By assigning the results of coating thickness distribution, the simultaneous build-up of coating computational domain is achieved by ALE moving mesh method. The validation of the FEA (finite element analysis) model was carried out by measuring the coating surface temperature via an infrared imaging camera. The effects of nozzle traverse speed on the coating surface temperature as well as coating thickness in cold spray were also investigated. With the proposed model, it is able to study the actual coating build-up process as well as the heat transfer phenomena, which may provide more insights for the application in additive manufacturing and damage repair.

Numerical investigation of transient coating build-up and heat transfer in cold spray

A composite model was established to demonstrate the building-up process of the Al5056/In718 composite coating and to reveal a strengthened deformation of the Al5056 particle from the In718 particle. Results show that the building-up process of the Al5056/In718 composite coating is combined with the intercollision between the Al5056 particles and the In718 particle’s impact on the Al5056 particles. The addition of In718 particle induced an extra deformation of the Al5056 particles, induced by the kinetic energy of the In718 particles.

Building-Up Process of Cold-Sprayed Al5056/In718 Composite Coating

Inconel 718 is a high-strength metal alloy that exhibits excellent corrosion resistance. Cold spraying is a deposition technique that does not induce phase changes and so was used to form an anti-corrosion composite coating that was composed of an Al5056 matrix reinforced with In718. These composite coatings exhibited a higher corrosion potential and lower corrosion current than the pure Al5056 coating, which provided effective cathodic protection to Al substrate if the substrate corrosion was inadvertently initiated. The electrochemical impedance spectroscopy results indicated that it was the addition of In718 that improved the corrosion resistance of the cold-sprayed coatings. The In718 induced a compacting effect, which reduced the porosity of the coating, and this was found to be the primary reason for the increased corrosion resistance of the Al5056/In718 composite coatings compared to the Al5056 coating.

Microstructure and Corrosion Behavior of Cold-Sprayed Aluminum Alloy/Inconel Composite Coatings

In order to explore the main factors influencing the thermal conductivity of the cold sprayed Cu coating, four sets of Cu coatings with different deformation and annealing conditions were prepared ...

Study on thermal conductivity of cold sprayed Cu coating

To study the effect of deposition behavior of the reinforcement on microstructure and property of cold-sprayed metal matrix composite coating, four Al5056 composite powders containing 15 wt.%, 30 wt.%, 45 wt.% and 60 wt.% SiC were mixed to prepare the composite coatings by cold spraying. Effect of the SiC deposition behavior on microstructure, SiC distribution, micro-/nanohardness, surface residual stress and shear strength of the coatings were studied. Experimental results show that the increase in SiC content in the powder increased the SiC collision with the deposited SiC particles, which caused the difference in SiC content and distribution in the composite coatings. The SiC deposition behavior caused the SiC morphology to evolve from integrity to small cracks and complete fragmentation. The SiC deposition behavior effectively influenced its peening effect on the deformed Al5056 particles, that is, as the SiC fragmentation threshold arrived, the nanohardness, surface residual stress and shear strength of the coating showed the corresponding transition point. The surface residual stress state of the deformed Al5056 matrix could in turn affect the SiC deposition by increasing the SiC deposition efficiency at the minimum compressive stress.

Effect of SiC Deposition Behavior on Microstructure and Mechanical Properties of Cold-Sprayed Al5056/SiC Composite Coatings

In order to explore an easy way determining the hard particle distribution in the cold sprayed composite coatings. Four Al5056/SiC composite coatings were employed in the present study. One quantit...

M. Yu

Papers

Building-Up Process of Cold-Sprayed Al5056/In718 Composite Coating

Microstructure and Corrosion Behavior of Cold-Sprayed Aluminum Alloy/Inconel Composite Coatings

Study on thermal conductivity of cold sprayed Cu coating

Effect of SiC Deposition Behavior on Microstructure and Mechanical Properties of Cold-Sprayed Al5056/SiC Composite Coatings

Quantitative determination of SiC particles distribution of cold sprayed Al5056/SiC composite coatings