The diagram in the link yousupply shows gas heating prior to mixing with powder.
Digging into the patent papers
https://encrypted.google.com/patents/EP2834014A1?cl=en details "relatively cold" as in " The process is carried out at relatively low temperatures, below the melting point of the substrate and the particles to be deposited, with a coating being formed as a result of particle impingement on the substrate surface. The fact that the process takes place at relatively low temperature allows thermodynamic, thermal and/or chemical effects, on the surface being coated and the particles making up the coating, to be reduced or avoided."
Further into the patent is the answer to my question
" Execution of a developed robot program has led to successful production the first directly manufactured titanium bicycle frame by cold spraying of titanium powder. The following detail is given by way of illustration and should not be taken as limiting. An aluminium scaffold, in the desired shape of a bicycle frame, was constructed by joining (welding) aluminium tubing with a wall thickness of 0.5mm. On this scaffold was deposited an approximately 1 mm thick titanium layer in some 45 minutes. This time could be reduced by faster titanium feed rates and higher robot speeds. Notably, this compares with a production time of approximately 2 days using traditional welding processes.
The cold spray titanium deposit is in the form of a shell around the scaffold. This unique structure did not involve any joining and welding. This is believed to represent a paradigm shift in how such complicated structures are made.
The scaffold material may be removed leaving a titanium shell by dissolution of the scaffold in a suitable solution, such as caustic soda.
However, it is equally possible that the scaffold structure may be kept as part of the titanium bicycle frame to exploit uniquely combined properties of titanium and aluminium in a low density composite structure.
Titanium contributes a number of desirable properties including strength, lightness and durability. Such properties are very beneficial in a high performance bicycle. In accordance with this embodiment it may also be possible to produce bicycle frames for more "mainstream" usage. In such cases light weight can be achieved using a combination of an aluminium scaffold (density 2.6 g/cm
3) and a cold sprayed titanium outer shell/layer (density 4.6 g/cm
3). This should be compared to a typical steel having a density of about 7 g/cm
3. The cost of the frame may be controlled by varying the ratio of aluminium to titanium used. The resultant frame will still be less bulky than an all aluminium frame which must use mass to compensate for relatively low strength of aluminium (compared with the strength of titanium).
(20min delay)