Abstract: Vapor deposition of metal films is carried out using as precursors metal compounds or complexes based on open pentadienyls and derivatives. The technique can be used favorably for transition metal depositions, and can be carried out photolytically or thermolytically. In certain cases, oxygen can be substituted for a terminal carbon atom.

Abstract: The deposition of a copper-containing layer on a substrate by decomposing, particularly by a CVD process, a compound corresponding to the formula (I)RO--Cu--L (I)in whichR represents a 1-aryl lower alkyl group, a branched, optionally substituted alkyl group with 3 to 6 carbon atoms, or an aryl group, andL represents (C1 to C6-alkyl)isonitrile, aryl isonitrile, carbon monoxide, dialkylaminodifluorophosphane, organyl difluorophosphane, triaryl phosphane, trialkyl phosphane, trifluorophosphane, or trichlorophosphane,is described, together with previously unknown compounds of formula (I) which may be used in the process.

Abstract: A pack cementation coating tape such as a nickel aluminide coating tape includes a reactive metal such as aluminum, a filler such as aluminum oxide, and a halogen carrier such as ammonium chloride held together by fibrillated polytetrafluoroethylene. The tape is useful in coating localized areas of nickel containing alloys to provide a nickel aluminide surface coating. The coating is formed by positioning the tape over the metal surface and heating the tape to a temperature of about 1250.degree. F. wherein the element metal such as aluminum reacts with the halogen carrier and in turn reacts with nickel on the surface of the nickel alloy to form the nickel aluminide coating. A masking tape formed from a separating layer, a brazing alloy layer and a nickel layer can be used to mask localized portions of the surface to prevent coating at these areas.

Abstract: A heat resistant stainless steel coated by diffusion of aluminum and a method of aluminum diffusion coating for heat resistant stainless steels containing nickel and chromium. The stainless steel is buried in a diffusion coating pack powder composed of an aluminum source, an activator and inert filler materials. The coating is heat treated to form a chromium-rich intermediate layer without forming an interdiffusion layer containing aluminide precipitates under an aluminide layer.

Abstract: The present invention is a method for manufacturing inorganic membranes which are capable of separating oxygen from oxygen-containing gaseous mixtures. The membranes comprise a porous composite of a thin layer of a multicomponent metallic oxide which has been deposited onto a porous support wherein the pores of the multicomponent metallic oxide layer are subsequently filled or plugged with a metallic-based species. The inorganic membranes are formed by depositing a porous multicomponent metallic oxide layer onto the porous support to form a porous composite having a network of pores capable of transporting gases. The network of pores are plugged or filled by organometallic vapor infiltration to form an inorganic membrane having essentially no through porosity.

Abstract: An improved process is disclosed for depositing a layer of metal on a semiconductor wafer wherein a shadow ring normally engages the end edge of the front surface of the wafer to inhibit deposition of the metal on the backside of the wafer and a barrier or nucleation layer is deposited on the unshielded portion of the front surface of the wafer prior to the deposition of the metal layer thereon, and wherein gases used to form the metal layer may contact and react with underlying materials on the front surface of the wafer beneath the shadow ring.

Abstract: A chemical vapor deposition process for growing a thin metallic film of copper or gold on a substrate includes providing a starting material composed of a .beta.-ketonato type metal complex of gold or copper in a heated container; preparing a carrier gas for the starting material which is composed of hydrogen as a reducing agent and at least one electron donating substance which bonds to and forms a molecular compound with the starting material by donating an electron to the starting material; passing a flow of the carrier gas through the heated container containing the starting material to form the molecular compound in situ and provide a flow of a gas mixture; introducing the flow of the gas mixture into a reaction chamber in which a substrate is positioned; and growing gold or copper on the substrate by thermally decomposing the molecular compound and any remaining starting material under temperature conditions effective therefor.

Abstract: A method is provided for forming films comprising Fe, Ru or Os employing the techniques of chemical vapor deposition to decompose a vapor comprising an organometallic compound of the formula (a): (CO).sub.4 ML or (b): M.sub.2 [.mu.-.eta.:.eta..sup.4 -C.sub.4 ](CO).sub.6 ; wherein L is a two-electron donor ligand and each R is H, halo, OH, alkyl, perfluoroalkyl or aryl; so as to deposit a coating comprising one or more of said metals on the surface of a substrate.

Abstract: A method for selectively forming thin films by CVD in which at least two substrates are exposed to a decomposable gas, and one of the subsrates is independently heated to selectively form a film on the heated substrate. The invention further comprises a step of measuring an electrical property of the film during deposition.

Abstract: A method for forming interconnections in microelectronic devices, including interconnections through small vias between different layers in the microelectronic devices include the spin coating of a film comprising a polyoxometalate and an organic material on the substrate. The film is optionally patterned by lithography, the polymer is removed, and the polyoxometalate is reduced to a metal layer. The metal layer may in one embodiment provide a nucleating zone for the deposition of metal.

Abstract: An improved method is provided for depositing a thin copper aluminum alloy film on a patterned silicon substrate. A copper base layer conforming to the existing pattern is initially formed on the surface of the substrate, followed by contact with vapors of an aminealane compound, which causes aluminum to be selectively deposited on the copper base layer portion of the substrate. Preferably, copper is applied to a diffusion barrier surface such as tungsten using chemical vapor deposition from a complex of copper (I) perfluoroalkyl-.beta.-diketonate and an olefin or silylolefin. The entire process of developing an alloy film can be carried out without exceeding 200.degree. C.

Abstract: An aluminide coating is applied to a portion of the surface of an article that already has a thermal barrier coating system in place over another portion of its surface. The portion of the surface to be coated is contacted, at elevated temperature, with an aluminide coating source material that is a mixture of from about 18 to about 45 weight percent of a metallic source of aluminum and the balance ceramic particles. The metallic source of aluminum may be pure aluminum or an aluminum-containing alloy. No halide activator is present in the aluminide coating source material.

Abstract: A method for stabilizing and lubricating elastomeric material includes depositing a first material film layer of carbide forming material by high energy level vacuum plating onto the elastomeric material to thereby stabilize free carbon atoms present in the elastomeric material. A second material film layer is deposited by high energy vacuum plating onto the first material film layer to thereby lubricate the elastomeric material.

Abstract: A method for forming hermetic coatings on optical fibers by hot filament assisted chemical vapor deposition advantageously produces a desirable coating while maintaining the pristine strength of the pristine fiber. The hermetic coatings may be formed from a variety of substances, such as, for example, boron nitride and carbon.

Abstract: Control of the local environment during pulsed laser removal of thin film circuit metallurgy is used to change the nature of the top surfaces. Interconnecting such laser treated surfaces with LCVD films results in different growth morphologies, dependent on the nature of the surface created and the debris generated during the ablation process. Flowing helium across the surface during the ablation process results in improved growth morphologies for the same laser writing conditions. A low power laser scan is used to induce metal deposition on the substrate without surface damage. This is followed by several scans at an intermediate laser power to deposit the desired thickness of metal (e.g., about 8 .mu.m). Lastly, a high power laser scan is used, either at the points of intersection between the existing metallurgy and the metal repair or across the entire deposit area. Thermal spreading or blooming is reduced by modulating the intensity of the laser source.

Abstract: An article is coated with a thermal barrier coating system to increase its thermal cyclic spallation life. A single layer bond coating is applied to the surface of the article to a surface roughness in the range of 200 to 600 microinches RA by low pressure plasma spraying of coarse MCrAlY alloy particles into the surface. A metal selected from aluminum and its alloys is applied to the bond coating by aluminiding and is diffused into the bond coating to provide an aluminum-rich bond coating metal outer surface, while substantially retaining the surface roughness of about 2300 to 600 microinches RA. A metal oxide thermal barrier coating layer is then applied onto the aluminum-rich bond coating outer surface.

Abstract: A method for coating articles, such as gas turbine blades, with a coating of variable thickness by securing a shield having one or more holes extending therethrough to the article thereby defining a shielded portion of the article, exposing the article and shield to a metal-bearing gas which is circulated around the article to deposit a metallic coating thereon, wherein the circulation of the gas adjacent the shielded portion of the article is restricted by the presence of the shield, thereby producing a substantially thinner coating on the shielded portion of the article than on the unshielded portion.

Abstract: A thermal decomposition cell for producing a molecular beam from a material gas, includes: a crucible maintained at a given temperature necessary for thermal decomposition of the material gas which is effused in the crucible in a given direction; and a thermal decomposition baffle provided in the crucible and heated to a given temperature necessary for thermal decomposition of the material gas for producing the molecular beam by thermal-decomposing of the material gas such that the material gas is baffled in substantially all directions, the thermal decomposition baffle being made of a given metal to cause the thermal decomposition of the material gas. The thermal decomposition baffle may comprise a fiber or a cloth made of the metal loaded in the crucible.

Abstract: This invention provides a process for forming with high selectivity an Al film having good electrical conductivity at the uncoated portions of a substrate coated with a masking material by means of chamical vapor deposition, using an Al selective deposition material having good electrical conductivity without subjecting it preliminarily to cracking, characterized in that the process employs a molecular compound of trimethyl aluminum and dimethyl aluminum hydride as a starting material gas. This invention also provides an Al selective CVD material characterized in that it is an organic Al compound represented by the following formula:(CH.sub.3).sub.3 Al--(CH.sub.3).sub.2 AlHobtained through intermolecular binding between trimethyl aluminum and dimethyl aluminum hydride.

Abstract: A method for the powder pack coating of hollow structural components is performed with spherical powder particles of a donor metal in which the hollow component is embedded. During the embedding, the component is subjected to a tumbling motion about several spatial axes to fill all cavities in the component. After the powder pack coating process the cavities of the component are cleared of any excess powder particles under the action of a gas stream. This method is suitable especially for coating engine blades having cooling ducts and cooling air holes, such as turbine blades. The effect of the forced air flow through the internal cavities for the removal of excess powder out of the hollow component is enhanced by simultaneously vibrating the component.

Abstract: Fluorinated alkoxy compounds of copper, copper-calcium, copper-strontium, and copper-barium having the structure:Cu.sub.w (OR).sub.x Y.sub.y L.sub.z ; orM.sub.a Cu.sub.b (OR).sub.c,in which 1.ltoreq.w.ltoreq.4; R is a fluorinated alkyl group; x.gtoreq.1; Y is an alkoxy or alkyl group without beta-hydrogen; y.gtoreq.0; w.ltoreq.(x+y).ltoreq.2w; L is a Lewis base; 1.ltoreq.z.ltoreq.2w; M is Ca, Sr, or Ba; and 1.ltoreq.a.ltoreq.4; 1.ltoreq.b.ltoreq.4; (b+2a).ltoreq.c.ltoreq.2(b+a), have exceptionally high volatilities, and hence low vaporization or sublimation temperatures, at 10.sup.-5 torr. They are superior precursor compounds for chemical vapor deposition of thin films on substrates under vacuum, and for sol-gel processing.

Abstract: This invention relates to an improved pack mixture composition useful for the formation of a SiC pack cementation coating for protecting a carbonaceous substrate from degradation at temperatures above about 800.degree. F. comprising: Si from about 15% to about 50% by weight of the total composition; B up to about 25% by weight of the total composition when present; SiO.sub.2 from about 0.01% to about 3% by weight of the total composition; and SiC from about 40% to about 85% by weight of the total composition and method thereof.The invention further relates to a cork release agent composition for providing the clean release of spent pack composition from a carbonaceous substrate.

Abstract: A crucible used in a powder pack plating process has an aperture below the upper surface of the powder pack to allow a density driven flow of the plating gas generated by the powder pack to move through the powder pack.

Abstract: A novel process for the selective deposition of solid-phase materials is disclosed, which process requires only the modulation of a single auxiliary gas within a suitable reactor assembly. According to the disclosed method, selective area deposition can be obtained on any desired microelectronic substrate by the creation of a vapor-phase chemical equilibrium system capable of deposition and etching the material to be deposited. The vapor-phase system is designed around a single reversible reaction wherein the material to be deposited equilibrates between that solid phase and its vapor-phase constituent species. By modulating an auxiliary gas flow into the reactor assembly, alternating deposition and etching processes can be obtained to yield an overall process which results in net overall selective and uniform deposition.

Abstract: A process for forming a deposited film on a substrate in the absence of a plasma is conducted by generating in an activation space an activated species capable of chemically reacting with a compound for film formation and introducing into a film-forming space having the substrate, the activated species and the compound for film formation. The compound for film formation has the general formula R.sub.n M.sub.m wherein R is a hydrocarbon radical, M is an element selected from one of Groups II-IV, n is an integer equal to the valence of M and m is a positive integer equal to the valence of R. The film-forming space is remote from the activation space. The activated species initiates a chemical reaction with the compound for film formation sufficient to generate chemical species of said film-forming compound capable of directly forming the deposited film.

Abstract: A semiconductor substrate or other object (32) for vapor deposition is mounted on a susceptor disk (16) which rotates about a vertical axis. Chemical vapor flows downwardly through a passageway (14) onto the object (32). A radial space (14a) is provided between the periphery of the disk (16) and an adjacent inner wall (12a) of the passageway (14). Rotation of the disk (16) urges a portion of the vapor flow (60) to be deflected from the disk (16) and the wall (12a) of the passageway (14) upwardly to cause deleterious recirculation of the vapor above the disk (16). A flow guide (52) disposed in the passageway (14) above the disk (16) has an upstream converging section (52a) which causes the flow (56) of vapor to accelerate, and a downstream diverging section (52b) which causes the accelerated flow (58) to expand downwardly and radially outwardly so as to interact with, and prevent upward movement of the deflected portion of the flow (60) and thereby suppress recirculation of the vapor.

Abstract: Method and apparatus for formation of an alloy thin film, or a mixed metal oxide thin film, on a substrate at relatively low temperatures. Precursor vapor(s) containing the desired thin film constituents is positioned adjacent to the substrate and irradiated by light having wavelengths in a selected wavelength range, to dissociate the gas(es) and provide atoms or molecules containing only the desired constituents. These gases then deposit at relatively low temperatures as a thin film on the substrate. The precursor vapor(s) is formed by vaporization of one or more precursor materials, where the vaporization temperature(s) is selected to control the ratio of concentration of metals present in the precursor vapor(s) and/or the total precursor vapor pressure.

Abstract: Fine-grained and/or equiaxed coatings, substantially free from columnar structure, are deposited on substrates by chemical vapor deposition by directing the flow of reactant gases to the substrate with high velocity and in close proximity thereto, most often at a velocity gradient of at least about 1050 and preferably at least about 2000 cm./cm.-sec. The deposition process is preferably conducted while moving the substrate so as to coat large areas thereof. By this method, tungsten and/or rhenium X-ray targets having excellent properties under conditions of rapid temperature cycling may be produced.

Abstract: A process for forming an additive-containing Al film of good quality according to the CVD method utilizing an alkyl aluminum hydride, a gas containing an additive and hydrogen, which is an excellent deposited film formation process also capable of selective deposition of additive-containing Al.

Abstract: A process for forming a metal film comprises the steps of arranging a substrate in a space for formation of the film, introducing an alkylaluminum hydride gas and hydrogen gas into the space and heating directly the substrate to form a metal film comprising aluminum as main component on the surface of the substrate.

Abstract: A highly pure thin metal film having a nanocrystalline structure and a process of preparing such highly pure thin metal films of, e.g., rhodium, iridium, molybdenum, tungsten, rhenium, platinum, or palladium by plasma assisted chemical vapor deposition of, e.g., rhodium(allyl).sub.3, iridium(allyl).sub.3, molybdenum(allyl).sub.4, tungsten(allyl).sub.4, rhenium(allyl).sub.4, platinum(allyl).sub.2, or palladium(allyl).sub.2 are disclosed. Additionally, a general process of reducing the carbon content of a metallic film prepared from one or more organometallic precursor compounds by plasma assisted chemical vapor deposition is disclosed.

Abstract: The invention provides an apparatus for metal plating a substrate. The apparatus includes a chamber adapted to receive metal carbonyl gas. The chamber includes an infrared transparent window. The infrared transparent window has a cooling passage filled with liquid coolant. The liquid coolant has a temperature below which decomposition of the metal carbonyl gas occurs. The liquid coolant prevents decomposition of the metal carbonyl gas on the infrared transparent window. The liquid coolant also is substantially infrared transparent for allowing infrared radiation through the infrared transparent window and cooling passage into the chamber. An infrared radiation source sends infrared radiation into the chamber through the infrared transparent window and cooling passage to heat the substrate to a temperature at which decomposition of the metal carbonyl gas occurs.

Abstract: A method is disclosed for the volatilization and transport of an alkaline earth metal precursor. The presence of an amine or ammonia significantly increases transport of the voltalized alkaline earth metal precursor as compared to transport under the same conditions but without the amine or ammonia.

Abstract: The present invention is designed to improve a method of deposition of coatings upon a metal or alloy substrate. The coating comprises aluminum or aluminide material interdiffused with a transition metal deposited by chemical vapor deposition which utilizes organometallic precursors to facilitate the deposition of the transition metal. The improvement permits better control of the process and permits coating of complex substrates including those with internal passages or holes. In the embodiment involving a first deposition of aluminum or aluminide coating, applicants have achieved deposition thereon of the transition metal. Platinum is the preferred transition metal to be used in the subject method. A product is taught. This product can be a component from a gas turbine engine.

Abstract: A method for diffusion coating a workpiece with chromium (Cr), silicon (Si), aluminum (Al), or boron (B) by placing coated ceramic alumino-silicate fibers next to the workpiece and heating to diffuse the diffusion coating into the workpiece. A ceramic carrier is fabricated from the alumino-silicate fibers woven into a predetermined fashion. Alternately the ceramic carrier may be an elongated ceramic carrier. The aqueous diffusion coating composition is applied to the ceramic carrier and then the ceramic carrier is heated at a temperature of between about 150.degree. F. to 250.degree. F. prior to positioning the ceramic carrier proximate a surface of the workpiece. The ceramic carrier and the workpiece are subjected to an elevated temperature in a controlled environment for a sufficient time to cause at least one diffusion element to diffuse into the workpiece to provide the diffusion coating for the external, the internal, or both surfaces of the workpiece.

Abstract: A process for coating metal on a substrate. The process uses organometallic compounds such as (trimethyl)(cyclopentadienyl) platinum in the presence of a reducing fluid such as hydrogen gas to produce high purity films capable of selective deposition on substrates containing, for example, tungsten and silicon. The films are deposited using chemical vapor deposition (CVD) or gas phase laser deposition. The invention also comprises devices made from the process of the invention.

Abstract: A nickel-base superalloy is subjected to a diffusion chromizing that supplies a chromized diffusion case, the outer surface of which contains excess alphachrome phase, and then contacting the diffusion case with an aqueous solution of alkali metal permanganate and alkali metal hydroxide until the desired amount of alphachrome phase is eliminated.

Abstract: An atmospheric pressure chemical vapor deposition (APCVD) system for doping indium-oxide films with both tin and fluorine to produce dual electron donors in a non-batch process. The APCVD system has a conveyor belt and drive system for continuous processing through one or more reaction chambers separated by nitrogen purge curtains. A substrate passing through the system enters a muffle heated by several heaters and the reaction chambers are supplied by a source chemical delivery system comprising an oxidizer source, a fluorine chemical source, a nitrogen source, rotometers for the above sources, a mass flow controller, a tin chemical bubbler, heated lines, an indium chemical bubbler, a pair of water baths with heaters, and associated valving.

Abstract: In a process for the production of thin films and epitaxial layers by gas-phase deposition, intramolecularly stabilized organometallic compounds are employed as a source of metal.

Abstract: Process for producing a copper plated resin article by forming a uniform copper coating having excellent adhesive strength on a fiber-reinforced or unreinforced thermoplastic or thermosetting resin article having a heat deformation temperature higher than 165.degree. C. The resin article is heated along with a source of copper formate under a reduced pressure or in a non-oxidative atmosphere to a temperature in the range above 165.degree. C. but lower than the heat deformation temperature of the resin article. The process makes it possible to produce a resin article having formed thereon a copper layer having an excellent adhesive strength by a very simple manner, and the resin article thus obtained can be used in various industrial fields.

Abstract: A structural component of titanium or titanium alloy is provided with a protective coating made substantially of an oxidation resistant and diffusion inhibiting base layer (2), an intermediate layer (3) forming a titanium fire inhibiting layer, and a cover layer (4) forming a passivating sealing layer. These layers are applied by various methods.

Abstract: A process is provided for selectively depositing copper films on metallic or other electrically conducting portions of substrate surfaces by contacting the substrate at a temperature from 110.degree. to 190.degree. C. with a volatile organometallic copper complex, in the gas phase, represented by the structural formula: ##STR1## wherein R.sup.1 and R.sup.3 are each independently C.sub.1 -C.sub.8 perfluoroalkyl, R.sup.2 is H or C.sub.1 -C.sub.8 perfluoroalkyl and L is carbon monoxide, an isonitrile, or an unsaturated hydrocarbon ligand containing at least one non-aromatic unsaturation.

Abstract: A thin copper film is formed by CVD, by (a) forming a gas stream containing a copper halide, followed by introducing said gas stream into a CVD reaction chamber having a heated catalytic metal filament arranged herein, (b) introducing hydrogen gas into the CVD reaction chamber for activation of said hydrogen gas by the heated catalytic metal filament, and (c) carrying out the reaction between the copper halide contained in the gas stream introduced in step (a) and the hydrogen activated in step (b) near the surface of a substrate arranged within the CVD reaction chamber so as to deposit a thin copper film of copper on the substrate surface.

Abstract: An alcohol having an alpha hydrogen with the remaining groupings attached to the carbon atom being either hydrogen or an alkyl group having from 1 to 5 carbon atoms, preferably isopropanol, is added to the flow stream of a copper chelate gas, preferably a copper diketonate, the copper diketonate preferably being Cu(hfac).sub.2 or a composition identical thereto wherein one or more of the fluorine atoms is replaced by one of hydrogen atoms, and alkyl group having from one to five carbon atoms and a gas, preferably a reducing agent, preferably hydrogen. As a second embodiment, some or all of the copper can be replaced by aluminum to provide either Al(hfac).sub.3 or a combination of Cu(hfac).sub.2 and Al(hfac).sub.3.

Abstract: Volatile liquid organometallic copper complexes are provided which are capable of selectively depositing a copper film onto metallic or other electrically conducting portions of a substrate surface under CVD conditions. These organometallic copper complexes are represented by the structural formula: ##STR1## wherein R.sup.1 and R.sup.3 are each independently C.sub.1 -C.sub.8 perfluoroalkyl, R.sup.2 is H, F or C.sub.1 -C.sub.8 perfluoroalkyl, R.sup.4 is H, C.sub.1 -C.sub.8 alkyl, or Si(R.sup.6).sub.3, each R.sup.5 is independently H or C.sub.1 --C.sub.8 alkyl and each R.sup.6 is independently phenyl or C.sub.1 -C.sub.8 alkyl. A process for depositing copper films using these organometallic copper complexes is also provided.

Abstract: A beam or flow of a reactive or metastable precursor such as a hydride or organometallic compound is created, and this beam or flow is used to treat (e.g. dope or coat or otherwise modify) a substrate, e.g. an advanced material such as a semiconductor layer, a photovoltaic cell, or a solar cell. The beam or flow can also be directed into a storage zone so that the precursor or precursors can be collected for future use. The beam or flow is created in an apparatus comprising at least three zones. Zone 1 is irradiated with microwave energy to generate a reactive gas rich in free radicals (e.g. rich in H.sup.., CH.sub.3.sup.., etc.) zone 2 (downstream from zone 1) is substantially free of microwave energy and contains a target which is impinged upon by the free radicals and becomes a source of the precursor; zone 3 (downstream from zone 2) is where the precursors are either collected for storage or are used to treat the substrate. In a typical apparatus of this invention, a feed gas such as H.sub.2 or CH.sub.

Abstract: A method for forming connections between copper conductors disposed on a substrate includes the steps of coating the copper conductors with a layer of nickel, exposing the coated copper conductors to a gas which includes a tungsten-bearing compound, and irradiating the substrate with a laser beam to deposit the tungsten between the copper conductors. A system for forming connections between copper conductors disposed on a substrate, includes means for coating the copper conductors with a layer of nickel, means for exposing the coated copper conductors to a gas which includes a tungsten-bearing compound, and means for irradiating the substrate with a laser beam to deposit the tungsten between the copper conductors.

Abstract: Improved adherence of oxide wear layers on hard metal or cemented carbide substrates is obtained by providing a thin surface-oxidized bonding layer comprising a carbide or oxycarbide of at least one of tantalum, niobium or vanadium, optionally adding aluminum to the bonding layer, and finally providing an outer oxide layer layer.

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: The surface properties of iron or ferrous alloy are improved by borosiliconizing the surface by contact with a stream of reducing gas containing hydrogen, optionally with an inert gas, to which a gaseous halide or hydride of boron and silicon have been added, either together or sequentially. The temperature of treatment is elevated, e.g. above 350.degree. C., but below 1200.degree. C. Diffusion coatings of both boron and silicon are formed in the ferrous surface. Typical surces of boron and silicon inlude boron trichloride, diborane and silane.