Abstract: A method of closing a canal which has been formed in a wall of a component such as a heat exchanger for rocket combustion chamber walls comprises inserting an elongated filler into the canal so as to leave at least one end of the filler which projects out of the canal, filling the remaining space with an electrically conducting melting substance such as a wax, engaging the projecting end of the filler to pull it out of the substance in the canal and to leave the expanding chamber in the substance, an electroplating metalloplastic material onto the component to form a cover over the canal and the substance therein. Electroplating can be carried out without causing any heat which is produced thereby to affect an expansion in the canal which would disturb the electroplating or the formation of the component.

Abstract: A method for galvanic deposition of nickel from an electrolyte containing nickel sulfamate and nickel chloride is disclosed wherein the formation of intermediate products resulting from the oxidation of nickel sulfamate and the escape of anode sludge into the electrolyte are controlled to such an extent so as to reduce the amount of sulfur incorporated in the deposition to less than about 15 ppm.This results in avoidance of brittleness in the nickel deposition at high temperatures and allows the coated article to be welded. These properties were difficult or impossible to obtain in the prior art processes.

Abstract: In forming the inner wall for the combustion chamber and/or thrust nozzles of an liquid rocket engine which is shaped with inwardly directed projections to form cooling ducts closed outwardly by the outer wall, a reinforcing layer is electroplated at least on the radially inner surfaces of the inwardly directed projections. The inner wall is rotatably supported within an electrolyte bath with the material-depositing electrode located on the central axis of the inner wall and only the surface to receive the reinforcing layer is located below the surface of the bath. The reinforcing layer is provided only over a part of the axially extending length of the inner wall and a tapering transition section is provided from the radially inner surface of the reinforcing layer to the inner surface of the inner wall by gradually lifting or lowering the inner wall within the electrolyte bath during the electroplating operation.