Warm Spray has demonstrated that it could fabricate comparatively dense metal coatings keeping with high purity during atmospheric process. Its key technology is the control of the temperature of the supersonic combustion jet prior to supplying feedstock.

So far, even titanium (Ti), known as one of materials difficult for the atmospheric process, could be deposited with less oxidation and higher packing density of the resulting coatings. For example, the coatings’ packing density with oxygen content were 97.7vol% with 0.28mass% and 98.9vol% with 0.92mass%.

Further densification of Ti coatings was achieved by bi-modal size distribution of feedstock powder upon Warm Spraying. When bigger Ti particles was mixed with the usual feedstock powder under 45 mm, the packing density was increased to 99.1vol% simultaneously with the less oxygen content of 0.26mass% , which was comparable to the level of feedstock powder.

The densification is caused by enhancement of the peening effect by big particles and by closely packing of the big and small particles with the optimized mixture ratio.