Abstract: In a process for the simultaneous deposition of a protective coating, e.g. an aluminuim based coating, on internal and external surfaces of heat-resistant alloy parts, the parts are placed in a box containing a donor material, preferably in the form of granules, comprising the metal to be deposited, and an activator separate from the donor and comprising at least an anhydrous powder of chromium fluoride CrF.sub.3 to provide a source of fluorine. The box is heated to a temperature above 1000.degree. C. and a controlled flow of a carrier gas, reducing or neutral, is introduced into the box so as to establish a circulation of gases in the box whereby fluorinated vapors from thermal decomposition of the CrF.sub.3 activator contact the donor to form a volatile fluoride of the metal to be deposited, and the volatile vapor is carried into contact with the external and internal surfaces of the parts to be coated to deposit the coating thereon.

Abstract: A method for coating a heat engine part, particularly a turbo-machine part made of a superalloy and adapted for use in aeronautical applications, comprises electrophoretically depositing a metallic structure of cellular form with uniformly disposed cells of predetermined size. The deposition is performed using an electrophoresis bath containing methanol, aluminum chloride as an electrolyte, and a powder containing Cr, Al, Y, Ta and Ni. The cellular metallic structure is consolidated by a sintering treatment, which may be reactive, or metallization, preferably in the vapor phase, and the coating is completed by applying a ceramic material by plasma spraying.

Abstract: In a process for the simultaneous deposition of a protective coating, e.g. an aluminium based coating, on internal and external surfaces of heat-resistant alloy parts, the parts are placed in a box containing a donor material, preferably in the form of granules, comprising the metal to be deposited, and an activator separate from the donor and comprising at least an anhydrous powder of chromium fluoride CrF.sub.3 to provide a source of fluorine. The box is heated to a temperature above 1000.degree. C. and a controlled flow of a carrier gas, reducing or neutral, is introduced into the box so as to establish a circulation of gases in the box whereby fluorinated vapors from thermal decomposition of the CrF.sub.3 activator contact the donor to form a volatile fluoride of the metal to be deposited, and the volatile vapor is carried into contact with the external and internal surfaces of the parts to be coated to deposit the coating thereon.

Abstract: A coating for a heat engine part, particularly a turbo-machine part made of superalloy, comprises an electrophoretically deposited metallic structure of cellular form with uniformly disposed cells of predetermined size, the structure preferably being composed of M, Cr, Al, and Y, where M denotes Ni, Co, Fe and mixtures thereof. The cellular metallic structure is consolidated by a sintering treatment, which may be reactive, or metallization, preferably in the vapor phase, and the coating is completed by a ceramic material applied by plasma spraying.

Abstract: An elutriation apparatus for the purification and separation of powders of different densities includes several separating columns each provided at the lower part with a collector for grains receiving the fraction of powder of coarse granulometry and a device for the removal of the grains, and at the higher part a mechanism for the introduction of the powder and of the carrier or transporting fluid and an outlet for the carrier fluid and lighter fractions of the powder. The mechanisms for the introduction of the powder and of the carrier fluid includes at least one distributor tube disposed on the vertical axis of the column and descending within the latter approximately down to the powder collector. The base of the distributor tube has at least one opening discharging towards a deflector. Each column includes of two zones of different sections and the ratio of the sections is constant from one column to the other.