Deposition of tungsten coatings by detonation spraying

Abstract

Tungsten is a promising material for plasma-facing components of thermonuclear reactors. In the present work, tungsten coatings of low residual porosity (1%) were deposited on copper substrates by detonation spraying. Calculations of the particle temperatures and velocities were conducted for tungsten particles of different sizes using a previously developed model. These calculations helped selecting the spraying parameters enabling the formation of high-quality tungsten coatings in the experiments. A proper selection of the stand-off distance allowed achieving a high deposition efficiency of the powder (60%). The coatings showed a high bonding strength to the copper substrates, which was found to be 100 MPa, and a high hardness (850 HV). The coatings were shown to accumulate compressive stresses, which are beneficial for the structural integrity of coatings up to 500 μm thick.