Computer-Controlled Detonation Spraying: Flexible Control of the Coating Chemistry and Microstructure

Abstract

This article is a focused review aimed to describe the potential of the computer-controlled detonation spraying (CCDS) for producing and designing coatings with variable chemical and phase compositions and microstructure and promising properties. The development of the detonation spraying method is briefly analyzed from a historical perspective and the capabilities of the state-of-the art facilities are presented. A key advantage of the CCDS is the possibility of using precisely measured quantities of the explosive gaseous mixtures for each shot of the detonation gun and different oxygen to fuel ratios, which can create spraying environments of different chemical properties—from severely oxidizing to highly reducing. The significance of careful adjustment of the spraying parameters is shown using material systems that are chemically sensitive to the composition of the spraying environment and temperature. Research performed by the authors on CCDS of different materials—metals, ceramics, intermetallics and metal-ceramic composites is reviewed. Novel applications of detonation spraying using the CCDS technology are described.

Structure and Tribological Properties of Ni–Cr–Al-Based Gradient Coating Prepared by Detonation Spraying

“…We carried out detonation spraying using the CCDS2000 (LIH SB RAS, Novosibirsk, Russia ) setup that is described in [21,22]. Figure 1 presents a general view of the setup and a schematic illustrating the detonation spraying principle.…”

The effect of detonation spraying on the phase composition and hardness of Al2O3 coatings

“…The particle size of the powder is up to 22-45 µm. Detonation coatings were obtained on a computerized complex of new generation detonation spraying CCDS2000 (Computer Controlled Detonation Spraying), [21][22][23].…”

Obtained of powder coatings by detonation spraying

“…Each cycle is an injection under pressure of an air-fuel mixture, which in most cases consists of acetylene (C 2 H 2 ) and oxygen (O 2 ), after mixing, the explosion is initialized by setting it on fire (spark), due to the limited space of the oxidation-reduction reaction (OVR), this mixture is detonated, and a shock wave is generated, which transfers the sprayed particles to the substrate (realized the mechanism-shock pressing). The cycle ends after the installation purges with protective gas, mainly nitrogen (N 2 ), to clear the remaining undirected particles, as well as to prevent a "blowback" in which the flying from combustion products, due to the pressure difference inside and outside the products, are sucked back, which can lead to failure and destroying of the spraying equipment [6,7].…”

“…The key advantage of the detonation spray method is the ability to accurately control the amount of explosive gas mixture used for each shot of the detonation gun, which allows changing the degree of thermal and chemical effects of the detonation products on the particles of the sprayed powder [3][4][5][6][7]. Depending on the composition of the acetylene-oxygen explosive mixture, the O 2 /C 2 H 2 ratio, and the nature of the gas carrier, chemical interactions may occur between the individual phases of the composite particles [8].…”