Classifications

• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C32/00—Non-ferrous alloys containing at least 5% by weight but less than 50% by weight of oxides, carbides, borides, nitrides, silicides or other metal compounds, e.g. oxynitrides, sulfides, whether added as such or formed in situ
  • C22C32/001—Non-ferrous alloys containing at least 5% by weight but less than 50% by weight of oxides, carbides, borides, nitrides, silicides or other metal compounds, e.g. oxynitrides, sulfides, whether added as such or formed in situ with only oxides
  • C22C32/0015—Non-ferrous alloys containing at least 5% by weight but less than 50% by weight of oxides, carbides, borides, nitrides, silicides or other metal compounds, e.g. oxynitrides, sulfides, whether added as such or formed in situ with only oxides with only single oxides as main non-metallic constituents
  • C22C32/0026—Matrix based on Ni, Co, Cr or alloys thereof
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C32/00—Non-ferrous alloys containing at least 5% by weight but less than 50% by weight of oxides, carbides, borides, nitrides, silicides or other metal compounds, e.g. oxynitrides, sulfides, whether added as such or formed in situ
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C4/00—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge
  • C23C4/04—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge characterised by the coating material
  • C23C4/06—Metallic material
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C4/00—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge
  • C23C4/04—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge characterised by the coating material
  • C23C4/10—Oxides, borides, carbides, nitrides or silicides; Mixtures thereof
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
  • Y02T50/00—Aeronautics or air transport
  • Y02T50/60—Efficient propulsion technologies, e.g. for aircraft

Definitions

• the present invention refers to a particular metalloceramic composition, having at least three components, in the form of a powder mixture phase or sintered rod, for producing protective coatings on ferrous and non-ferrous metallic surfaces.
• the present invention has among its objects a method of applying said metallo-ceramic compositions in protecnve treatments on ferrous and non-ferrous metallic surfaces, various typically protective treatments highly resistant to high temperatures and the articles with the protective coatings thus obtained.
• the various metallo-ceramic compositions with at least three components, and the various protective treatments obtainable therewith together with ceramic oxides make it possible to obtain coatings resistant to thermal oxidation (anti-oxidant barrier), highly insulating and thermo-resistant coatings (thermal barrier) and electroinsulating coatings for high temperatures (electro-insulating barrier), useful for the protection of ferrous and non-ferrous metallic surfaces.
• the spray in the molten state technique which, without doubt, is the newest technique of protective coating, offers various advantages over the other processes. These advantages are determined by the possibility that this technique gives of depositing non-metallic materials. These materials can be oxides, carbides, borides, etc., either alone or in admixture with each other, in metallic, ceramic and metallo-ceramic compositions.
• metallo-ceramic compositions of three or more components, such as those resulting from the combination of one or more metal oxides of a ceramic nature, with I mixtures of chromium and nickel, in a ratio of 15 to 60 parts by weight of chromium, from 10 to 50 parts by weight of nickel and from 10 to 40 parts by weight of a ceramic oxide or of a mixture of at least two ceramic oxides, for each parts by weight of metallo-ceramic mixture.
• the ceramic components of the above-mentioned metallo-ceramic compositions are chosen from the simple or complex metal oxides, having a melting point not lower than 1900 C., such as the oxides of: aluminum, A1 in the alpha-form; zirconium, ZrO in the form stabilized with calciumor magnesiumor yttrium-oxide; magnesium oxide MgO; aluminum and magnesium oxides (spinel); calcium zirconate, CaZrO zirconium silicate, ZrSiO
• the simple oxides are preferably employed.
• the various metalloceramic compositions within the above-mentioned percentage limits of the metallic and ceramic components cited, are prepared by means of mixture of the powders of the components, within a granulometric range between l20 and +600 mesh, and preferably within a range of 230 and +325 mesh.
• the invention includes the method of application of the special protective materials used in the various treatments considered by spraying in the molten state. More particularly, the projection of the particles of the special materials in the molten state is generated by a controlled feeding of the materials to be applied, as a powder or sintered rods, into a jet of chemical or electric flame, preferably into an electric plasma arc-flame.
• a suitable generator of electric plasma flame such as that to which the present invention refers, briefly consists of a tungsten cup cathode and a copper nozzle anode, supported and connected by an electro-insulating interelectrodic element.
• the electric arc darting between the electrodes is stabilized and blown as a flame jet at very high temperatures (300015000 C.) by a suitable gas (argon, or nitrogen, or hydrogen, or their mixtures) which is introduced in suitable quantity into the interelectrodic cavity.
• argon, or nitrogen, or hydrogen, or their mixtures An example of such generator can be found in my application Ser. No. 552,490.
• the material to be applied preferably fed as a powder, and injected into the plasma jet by means of eolic transport, is dynamically molten and projected at high speed onto the surface to be coated, previously cleaned by sanding.
• the material to be applied is a sintered rod, it is statically molten.
• the use of metallo-ceramic compositions in the powder state is preferable.
• chromium 50% by weight of chromium, 25% by weight of nickel, 25% by weight of magnesium oxide.
• the composisition is particularly suitable for the protection of iron, steel, copper and brass.
• composition is particularly suitable for the protection of iron, brass and copper.
• composition 50% by weight of chromium, 25% by weight of nickel, 25 by weight of magnesium oxide.
• the composition is particularly suitable for the protection of iron, steel and copper.
• the composition is particularly suitable for the protection of iron, steel, copper and brass.
• composition is particularly suitable for the protection of iron, steel, copper and brass.
• composition is 4 particularly suitable for the protection of iron, steel, copper and brass.
• composition is particularly suitable for the protection of brass.
• composition is particularly suitable for the protection of steel and brass.
• the above metallo-ceramic compositions are applied by spraying in the molten state, using an electric plasma flame jet and feeding the material to be applied in the powder state, thereby depositing coatings whereby the treated ferrous and non-ferrous surfaces receive an eflicacious and undestroyable antioxidant protection. This is true even when the metallic elements reach, in mass, temperatures up to 800900 C., while being exposed to oxidizing surroundings.
• the antioxidant barrier coatings are applied in a thickness between 0025-05 mm. and preferably of 0.2 mm.
• a further object of the present invention is to apply protective coatings which, besides being a barrier against the destructive action of thermal oxidation, also constitute a thermoresistant insulation. That is, the coating is capable of withstanding higher surface temperatures while simultaneously containing the amount of heat transmitted through the wall of the protected metal element.
• Such coatings generally called thermal barriers, are known and are obtainable through metal oxide coatings of a ceramic character. Zirconium oxide is preferred.
• it is difficult, however, to anchor properly the ceramic coating because of the damaging effect of thermomechanical stresses which causes its separation. These stresses are particularly evident when the piece is brought up to the severe thermal working conditions.
• This invention has as an object to overcome this difficulty.
• the antioxidant barrier coatings obtained by using the above-mentioned metallo-ceramic compositions hereof represent a very good base layer for an effective and lasting bond of the thermal barrier coatings.
• the second layer having an antithermal character, is also realized through spray in the molten state by using a coating material consisting of one or more metal oxides deposed in admixture and/o1 singularly, selected from those having a melting point not lower than l,900 C. and a low coeflicient of thermal conductivity.
• the said second layer having antithermal character can consist of two or more hemi-layers or stratified films, obtained from mixtures of oxides and/or from one or more oxides, taken singularly and deposited.
• This second coating layer which is exclusively of ceramic character is obtained also by use of a chemical or electrical flame jet, preferably an electric plasma jet flame, using the operative modalities already described in the case of the protective treatment with a coating consisting of a single typical layer, as antioxidant barrier.
• the ceramic material required for the realization of the second layer of the coating is selected from aAl O ZrO stabilized with calcium oxide, magnesium oxide or yttrium oxide; ThO MgO or from composite oxides such as: spinel (MgO-Al O calcium zirconate; zirconium silicate (ZrSiO and preferably consists of stabilized zirconium oxide and/or aluminum oxide in the alpha form, which can be deposited in admixture and/0r singly.
• Electro-insulating barrier protective coatings are also obtainable by the present invention. These coatings like the thermal barrier type have very good bonding and temporal resistance, due to the utilization of the base layer obtained by using the special above-specified metallo-ceramic compositions.
• electro-insulating barrier is meant a coating having a ceramic character which represents an electric insulation and is effective at ordinary temperature and at high temperature up to 800-900" C. and above.
• Stabilized zirconium oxide is also included in the materials suitable for this purpose, but the material generally known to be the most suitable for this purpose is aluminum oxide. This is due to its dielectric characteristics and stability at both low and high temperatures. Many difliculties are encountered in obtaining a stable electro-insulating barrier coating on the metal surface when high temperatures are to be used.
• the percentage of failure is high, particularly at higher temperature values, for the same reasons specified in the case of thermal barriers."
• This can also consist of alpha type aluminum oxide alone or also of two oxides, preferably consisting of aluminum oxide a form, and of stabilized zirconium oxide and solely applied as hemi-layers one upon the other or vice versa.
• the invention therefore also offers the possibility of realizing protective coatings having combined antioxidant, antithermal and electro-insulating characteristics.
• the protective coating When in the second layer, having a ceramic character, that is an hemi-layer of zirconium oxide upon which is superimposed a covering aluminum oxide hemi-layer, is thus applied, the protective coating essentially assumes the electro-insulating characteristics which, however, are associated to the antithermal characteristics of the lower hemi-layer (zirconium oxide) and to antioxidant characteristics of the first chromium-nickel-ceramic oxide(s) layer.
• the aluminum oxide hemi-layer is first applied with the covering zirconium oxide hemi-layer superimposed thereon, the protective coating essentially assumes the antithermal characteristics of this last oxide, which however are associated to the electro-insulating characteristics of the lower hemi-layer (of aluminum oxide) and to the antioxidant characteristics of the first metallo-ceramic chromium-nickel-oxide (s) ceramic layer.
• the present invention therefore, relates not only to the special metallo-ceramic chromium-nickel-oxidets), the corresponding method of application and the relevant antioxidant barrier treatment but also to the treatments as antioxidant-thermal barrier, as antioxidant-electroinsulating barrier, as antioxidant-thermal-electro insulating barrier and as antioxidant-electro-insulating-thermal barrier.
• All the treatments of the various barriers have in common the application of metallo-ceramic layer of chromium-nickel oxide(s) in direct contact with the ferrous and non-ferrous metallic surface on which it exerts the antioxidant protection.
• the treatments of the bivalent or trivalent barrier type have the common characteristic of applying a second layer having a ceramic character, in which one or more metal oxides having a melting point not lower than 1,900 C. are deposited.
• the second layer having a ceramic character relating to bivalent or trivalent barrier treatment recourse can be made to the use of more than one oxide.
• two or more oxides can be applied either in the form of a compound projection, using a mixture of the components either in powder from or as a sintered rod, or in the form of hemi-layers or stratified films consisting of one comuponent using the single components in powder form or as a sintered rod.
• the deposition of hemi-layers or of stratified films in which zirconium oxide is laid on aluminum oxide or vice versa, is preferred, With the materials being fed as a powder.
• the material of the second layer having a ceramic character in the plurivalent (multi-purpose) barrier treatment is selected from the simple or compound oxides mentioned above and is preferably fed as a powder in granulometric compositions between and +600 mesh, and preferably between -230 and +325 mesh.
• the thickness of this second layer is comprised between 0.052.5 mm. 011 the basis of the characteristics relating to the conditions of use and to the geometry of the piece to be protected, the most suitable thickness is selected within this range.
• As general criteria for the selection it should be taken into account that, above a thickness of 0.5 mm., the more the mass temperature of the protected element decreases below 1000 C., the more increasing values can be usefully applied. The higher the surface temperature is above 1500 C., and not above 2500 C., the more the thickness of 0.5 mm. will be reduced to a minimum of 0.2 mm.
• the invention thus forms a considerable extension of the possibilities of employment of the usual metallic ferrous and non-ferrous materials as the construction material of industrial equipment and plant, where high temperatures are encountered.
• the invention appears particularly interesting for the protection of internal surfaces in contact with flames, of the elements forming the reactor of petrochemical plants for the production of acetylene for cracking of gaseous and/or liquid hydrocarbons.
• Example 1 Application of the protective treatment.Onto one side of a flat, rectangular iron sample of 60 x 50 x 4 mm. has been applied, after previous sanding, and using the spraying in the molten state technique with an electric flame argon plasma jet with a power of 14 kw., the antioxidant barrier treatment, consisting of a sole quaternary composite layer of a thickness of about 0.2 mm. was applied. A mixture of powders, containing 35% by weight of nickel, 30% by weight of chromium, 20% by weight of MgO and 15% by weight A1 0 of alpha form, in a granulometric fraction comprised between 200 and +325 mesh, was injected into the plasma jet by means of colic transport by nitrogen.
• the antioxidant barrier treatment consisting of a sole quaternary composite layer of a thickness of about 0.2 mm.
• Example 2 Application of the protective treatment.--Onto one side of a fiat, rectangular steel specimen of 60 x 50 x 4 mm., after previous sanding, using the spraying in the molten state technique with an electric flame argon plasma jet with a power of 14 kw., the antioxidant-thermal barrier treatment, consisting of two layers, was applied. The following working conditions were used.
• the first layer (composite ternary), of a thickness of about 0.2 mm., was obtained by using a mixture of powders containing 35% by weight of Ni, 30% by weight of Cr, 20% by weight A1 of alpha form and 15% by weight of MgO, in a granulometric fraction comprised between 200 and +325 mesh;
• the second layer (simple), of a thickness of about 0.1 mm., has been obtained by using only ZrO powder (stabilized with about of CaO), in a granulometric fraction comprised between 270 and +325 mesh.
• the powders were injected into the plasma jet by means of eolic transport by nitrogen.
• the antioxidant thermal barrier type protective coating is suitable to substain the tensions determined by a massive heating and to assure an excellent protection of iron against heat oxidation.
• Example 3 Application of the protective treatment.0nto one side of a flat, rectangular brass specimen of 60 x 50 x 4 mm., after previous sanding, using the spraying in the molten state technique using a jet of electric argon plasma flame with a power of 14 kw., the antioxidant thermal barrier treatment, consisting of two layers, was applied according to the following working conditions:
• the first (composite ternary) layer of a thickness of about 0.2 mm., was obtained using a mixture of powders containing 50% by weight of Cr, 25% by weight of Ni and 25% by weight of aAl O in a granulometric fraction comprised between 200 and +325 mesh;
• the second (simple) layer of a thickness of about 0.1 mm., was obtained using the sole ZrO powder (stabilized with about 5% of CaO), in a granulometric fraction comprised between 200 and +325 mesh.
• Example 4 Application of the protective treatment-Onto the face of a copper micro-oxygen-nozzle, provided with a jacket for cooling by water circulation, of the size of 36 mm. diameter and 85 mm. length, after previous sanding using the spraying in the molten state technique with a jet of electric argon plasma flame of a power of 14 kw., the antioxidant thermal barrier treatment, consisting of two layers was applied according to the following working conditions:
• the first (composite ternary) layer of a thickness of about 0.2 mm., was obtained using a mixture of powders containing 50% by weight of Cr, 25 by weight of Ni and 25% by weight of A1 0 alpha-form, in a granulometric fraction comprised between +200 and +325 mesh;
• the second (simple) layer of a thickness of about 0.1 mm., was obtained by using only ZrO powder (stabilized with about 5% of CaO), in a granulometric fraction comprised between 200 and +325 mesh.
• the powders were injected into the plasma jet by means of eolic transport by nitrogen.
• Example 5 Application of the protective treatment.Onto one side of a flat, rectangular iron sample of the size of 60 x 50 x 4 mm. has been applied, after previous sanding, by spraying in the molten state technique, using a jet of argon plasma electric flame with a powder of 14 kw., the antioxidant-electro-insulating barrier treatment, consisting of two layers, was applied according to the following working conditions:
• the first (composite ternary) layer of a thickness of about 0.2 mm., was obtained using a mixture of powders containing 40% by weight of A1 0 alpha-form, 30% by weight of Cr and 30% by weight of Ni, in a granulometric fraction comprised between 200 and j+325 mesh;
• the second (simple) layer of a thickness of about 0.1 mm. was obtained by using only a powder of A1 0 in alpha-form in a granulometric fraction comprised between 270 and +325 mesh.
• the powders were injected into the plasma jet by means of eolic transport by nitrogen.
• the applied coating presents excellent electro-insulating characteristics at high temperatures, due to the ceramic A1 0 layer.
• Example 6 Application of the protective treatment-Onto one side of a fiat, rectangular iron specimen 60 x 50 x 4 min, after previous sanding, by spraying in the molten state technique, using a jet of electric argon plasma flame with a power of 14 kw., the electro-insulating-heat barrier treatment, consisting of two layers realized, was deposited according to the following working conditions:
• the first (composite ternary) layer of a thickness of about 0.2 mm., was obtained by using a mixture of powders, containing 50% by weight of Cr, 25% by weight of Ni, and 25% by weight of A1 alpha-form, in a granulometric fraction comprised between 200 and +325 mesh;
• the second (simple) layer was obtained by using aluminum oxide and zirconium oxide in the form of stratified films of one component, depositing a thickness of 0.2 mm. of aAl O in a granulometric fraction comprised between 270 and +325 mesh, and subsequently apply onto said film a thickness of 0.15 mm. of Zr0 (stabilized with about 5% of CaO) in a granulometric fraction comprised between 270 and +325 mesh.
• the powders were injected onto the plasma jet by means of colic transport by nitrogen.
• the metaallic specimen was placed into a mufiie furnace, in air atmosphere, at a temperature of 800 C. and kept there for 250 hours.
• the coating applied onto the sample was observed to have excellent characteristics of resistance to thermal oxidation. It had remained perfectly anchored to the base surface, perfectly protecting the latter, while the surface of the base metal, on the opposite non-protected side, had undergone a strong corrosion by heat oxidation.
• the applied treatment presents excellent electro-insulating characteristics at high temperature, together with a high efiicacy in barring the heat, characteristics proper of the double ceramic layer.
• Metallo-ceramic compositions for application as a coating by means of spraying in the molten state technique, for the protection of ferrous and non-ferrous metallic surfaces against thermal wear and thermal oxidation comprising 15 to 60% by weight of chromium, to 50% by weight of nickel, and 10 to 40 by weight of at least one ceramic oxide, having a melting point 1900 C.
• Metallo-ceramic coating composition according to claim 1, wherein the ceramic oxide is selected from the group consisting of A1 0 alpha-form, ZrO -type stabilized with calcium oxide, with magnesium oxide and with yttrium oxide or MgO.
• Metallo-ceramic coating composition according to claim 1 wherein the ceramic oxide is selected from the group consisting of MgO.Al O in the form of spinel, calcium zirconate and ZrSiO 4.
• Metallo-ceramic coating composition according to claim 1 containing 50% by weight of chromium, 25% by Weight of nickel and 25% by weight of aluminum oxide A1 0 alpha-form.
• Metallo-ceramic coating composition according to claim 1 containing 30% by weight of chromium, 30% by weight of nickel and 40% by weight of aluminum oxide A1 0 alpha-form.
• Metallo-ceramic coating composition according to claim 1 containing 50% by weight of chromium, 25% by weight of nickel and 25 by weight of magnesium oxide, MgO.
• Metallo-ceramic coating composition according to claim 1 containing 25% by weight of chromium, 50% by weight of nickel and 25 by weight of magnesium oxide, MgO.
• Metallo-ceramic coating composition according to claim 1 containing 30% by weight of chromium, 35% by weight of nickel, 20% by weight of aluminum oxide A1 0 alpha-form and 15% by weight of magnesium oxide, MgO.
• Metallo-ceramic coating composition according to claim 1 containing 30% by weight of chromium, 35% by weight of nickel, 20% by weight of magnesium oxide, MgO, and 15% by weight of aluminum oxide, A1 0 alpha-form.
• Metallo-ceramic coating composition according to claim 1 containing 30% by weight of chromium, 35% by weight of nickel, 20% by weight of magnesium oxide, MgO, and 15% by weight of zirconium oxide, ZrO in the form stabilized with calcium oxide.
• Metallo-ceramic coating composition according to claim 1 containing 30% by weight of chromium, 35% by weight of nickel, 20% by weight of zirconium oxide, ZrO in the form stabilized with calcium oxide and 15 by weight of aluminum oxide, A1 0 alpha-form.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Physics & Mathematics (AREA)
• Plasma & Fusion (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Coating By Spraying Or Casting (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=11219530

Family Applications (1)

Country Status (6)

Cited By (13)

Families Citing this family (8)

• 1966
  • 1966-11-22 NL NL6616433A patent/NL6616433A/xx unknown
  • 1966-11-23 US US596400A patent/US3597241A/en not_active Expired - Lifetime
  • 1966-11-24 JP JP41077151A patent/JPS4815777B1/ja active Pending
  • 1966-11-25 CH CH1691666A patent/CH488819A/de not_active IP Right Cessation
  • 1966-11-28 GB GB53215/66A patent/GB1105199A/en not_active Expired
  • 1966-11-28 FR FR85212A patent/FR1505659A/fr not_active Expired

Also Published As

Similar Documents