Surface Technologies in Space Propulsion Manufacturing

ELECTROFORMING of THICK COATINGS

We use the electroforming process whenever it is uneconomic to create complex component geometries using conventional mechanical means. Unlike conventional electroplating, electroforming enables thick coatings to be built-up having a thickness of several millimetres.

We use electroforming during the production of rocket engine combustion chambers, expansion nozzles, high-frequency components, reflectors, edge protection profiles, concentrators etc.

Inspection of electroformed combustion chamber of the Vinci rocket engine

 

ELECTROFORMING by PULSE PLATING

Electroformed rocket engine combustion chamber

Pulse plating is a new electroforming technique that enables thick metallic layers to be built-up with excellent expansion, strength and ductile properties. This technique is used for our recently developed thrust chambers for Vulcain 2 and Vinci cryogenic rocket engines.

With the pulse plating technique, a source of electricity is applied in an electroplating bath. This source of pulse rectified electricity moves into the cathode area over a period of milliseconds and then into the anode area over the 0-point. The benefits of this technique are:

	The pulse curves significantly improves the mechanical properties of the pulse plated nickel.
	There is no need to add organic additives.
	Pulse plating enables significantly thicker layers to be built-up, for example with pulse plating, only two layers are required for the Vulcain 1 combustion chamber compared with 5 layers for the direct current technique. Consequently, the throughput time is reduced by more than 30 per cent.

 

FACILITIES

	Nickel-Baths up to 12,000 lt
	Acid Copper Baths of 3,000 lt

 

ELECTROFORMING by NICKEL SULPHAMATE
Nickel Sulphamate electroforming of combustion chambers cooling channels using the direct current technique.

Nickel Sulphamate electroformed rocket engine combustion chambers

FACILITIES

	Nickel-Baths from 1,300 lt to 8,000 lt
	Acid Copper Baths of 3,000 lt

 

 

ELECTROPLATING

We use surface coatings on aviation and aerospace components to improve the chemical and physical properties such as wear resistance, corrosion resistance and electrical conductance. The thickness of a standard electroplated coating is approximately 20 µm. Typical surface coatings are nickel, gold, silver and chrome.

Our primary surface coating process is used for satellites. For example the silver coating of antenna horns. This method is interesting in the high-frequency area since it enables complex geometries to be precision coated.

 

Part of the electroplating facility

DEWAXING

Cooling channel dewaxing

Dewaxing is an important process that we use during the production of rocket engine combustion chambers.

Within the combustion chamber, a copper liner contains numerous milled cooling channels. Before being nickel plated, these channels are filled with a conductive wax. After plating, the wax is completely removed from the channels using cleaning machines especially developed for the purpose.

CLEANING TECHNIQUES

The quality and performance of our rocket engines and thrust chambers is very dependant on the cleanliness of component parts before they are processed or integrated.

We use all of the industrial cleaning techniques, including spray cleaning and ultrasound cleaning for components ranging in size from minute injector elements to completely integrated combustion chambers.

Materials cleaned include plastics, ceramics and stainless steels. Surfaces coated with a reflective or gold-plated layer can be both pre- and precision cleaned.

 

ULTRASOUND CLEANING

Ultrasound cleaning is achieved by sound vibrations creating air bubbles producing 30,000 pressure and tension phases per second. The bubbles implode on the surface to be cleaned with asymmetric liquid flows, pressure spray and exceedingly high temperatures. There has to be a certain ultrasound performance density in the bath to ensure that there are sufficient vacuum bubbles for cleaning the entire surface. A good average value is 10 watts / litre.

 

FACILITIES

Ultrasound baths having a volume of 4,000 and 8,000 litres for cleaning liquid media (alkaline, neutral, IPA)

 

Ultrasound Cleaning

Spray Cleaning

If you require more detailed information on any of our products or services, then please contact us, indicating your particular areas of interest or intended application. Your enquiry will receive our best attention.