Thermal spray forming of high thickness deposits has a large potential for different industrial application domains including automotive, aeronautics and space. It is especially very suitable for liquid rocket engine thrust chamber manufacturing. For the application on LRE thrust chamber, the process presents the following advantages: recurring cost and production cycle reduction, large selection of materials, integral thermal barrier coating and architecture simplification. A technology program is being lead between SNECMA-SAFRAN and LERMPS laboratory since 1995 for full scale demonstration of the VPS process at HM7B scale (65 kN thrust class).

A step by step approach was used to overcome the identified difficulties. Several mock up parts were manufactured and evaluated, including burst pressure testing. The result on the specimens was very satisfactory as the experimental burst pressure reached 1100 bars for an elastic threshold estimated over 800 bars.

 

In parallel the first step, i.e. the spraying of the Narloy liner, for a prototype chamber was undertaken. The duration of the liner spraying was about 15 hours. The channels were defined to obtain the same pressure drop than the original HM7B design.