A novel strategy for the deposition of diamond based materials with Cold Spray and particle speed analysis

Cold Spray (CS) is a novel coating technology, whereby material in the form of powder is accelerated up to supersonic speed and deposited onto surfaces without crossing melting temperatures and in ambient conditions. The advantages of this method against convetionally “hot” deposition methods can be considerable due to the absence of Heat Affected Zones (HAZ) and micro-structural changes in the coating material. Metallurgical compatibility feedstock/substrate is also not a requirement with CS. The deposition of brittle materilals with CS is however diffcult and typically relies upon the pre-mixing with a ductile phase. Using this method, the acheivable hard phase vulume fraction in the coating is limited.
This work introduces a new strategy, wereby hard particles are not mixed but pre-coated with a ductile material so as to enable depostion. The authors have applied it to diamond depostion, using a grade pre-coated with a Cu and Ni. It was possible to manufacture thick coatings onto aluminium substrates at high rates, without adding binders or additional ductile phases, obtainig diamond volume