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US3345276A - Surface treatment for magnesiumlithium alloys - Google Patents

Surface treatment for magnesiumlithium alloys Download PDF

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US3345276A
US3345276A US332909A US33290963A US3345276A US 3345276 A US3345276 A US 3345276A US 332909 A US332909 A US 332909A US 33290963 A US33290963 A US 33290963A US 3345276 A US3345276 A US 3345276A
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lithium
magnesium
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temperature
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US332909A
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Robert A Munroe
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International Business Machines Corp
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    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
    • C25D11/02—Anodisation
    • C25D11/30—Anodisation of magnesium or alloys based thereon

Definitions

  • Magnesium and magnesium alloys have found wide acceptance as structural materials where there is need for both relatively high strength and light weight.
  • a variety of alloying materials have been added to magnesium in order to improve the mechanical strength properties of substantially pure magnesium.
  • One important class of such alloys are the magnesium-lithium alloys composed of 80% or more by weight of magnesium, and it is with particular reference to these that the invention derives its major area of application.
  • fluoride anodizing which consists generally of immersing the articles in an ammonium bifluoride solution and with the articles serving as electrodes, apply an alternating current thereto. This cleans in the conventional sense by dissolving and/or loosening surface impurities, and in addition forms a relatively impermeable protective surface layer or coating.
  • An important beneficial adjunct from this process is that surface purification is obtained without materially changing physical dimensions of the workpiece. Exemplary of this advantage in terms of another well-known prior art technique, to insure an equal degree of cleaning effect by more conventional acid ice pickling methods (chromic and mineral acid baths, for example) may require the removal of as much as 0.040 inch of base metal. It is an important aspect of the invention to provide an improved procedure for fluoride anodizing magnesium and magnesium alloy articles.
  • Exemplary of present known methods of cleaning magnesium alloy articles by fluoride anodizing is that set forth in the United States Patent 2,766,199, William F. Higgins the assignor to Magnesium Elektron Limited, Manchester, England.
  • Another object is the provision of a tightly adherent layer on the metal surfaces by an improved fluoride anodizing process.
  • Another object is the provision of a corrosion resistant surface as in the above objects which is not destroyed by subsequent heating to elevated temperatures.
  • Still another object is the applying over the special corrosion resistant surface a resinous sealing coat that is tightly and uninterruptedly adherent thereto and substantially free from included deposits of dirt, moisture and released occluded gases.
  • Another object of the invention is the provision of a surface treatment for magnesium and its alloys which is highly simplified and readily adapted to production manufacturing.
  • magnesium metals refers not only to substantially pure magnesium, but also to magnesium alloys of all kinds. More particularly, the term relates to magnesium-lithium which has exceptionally desirable physical characteristics, such as mechanical strength and toughness as well as the inherent light weight of magnesium.
  • the first step is to remove gross surface dirt, oil, grease and other such materials. This is best accomplished by the well-known process of hot vapor degreasing. By this process the workpiece being treated is exposed to the hot vapor of a material such as perchlorothene for sufficient time to remove surface impurities. Time for removal is usually a matter of minutes at the most. 7
  • Mill scale can be removed next optionally by either immersion in an appropriate acid solution (10% nitric or sulphuric acids, for example) or by a suitable mechanical technique.
  • an appropriate acid solution (10% nitric or sulphuric acids, for example) or by a suitable mechanical technique.
  • the latter can be accomplished by the application of dry pumice or by sanding, choice being dependent on the particular construction of the. workpiece.
  • those alloys containing lithium require heating treatment prior to anodizing. That is, the magnesium-lithiumarticles are next placed in a circulating air, or inert gas, oven Where they are heated to a temperature that is m the range of ZOO-255 C. for at least one hour. This heating cycle serves to drive out or precipitate lithium from those portions of the alloy closely adjacent the outer surfaces; As will be more fully appreciated later removing the lithium is an important preliminary step to obtaining the special anodized surface of the invention.
  • the magnesium-lithium articles or parts are removed from the oven and permitted to cool to room temperature, with the rate of cooling not being (3 critical for present purposes.
  • the cooled articles are immersed in continuously circulating water, which for best results should be heated water not exceeding ap proximately .150 F., and maintained therein for about 5 minutes. This washing operation removes the precipitated lithium from the metal surfaces which if not done would interfere with the subsequent fluoride anodizing.
  • the parts After cleaning in the above-described manner, and the additional heating step in the case of magnesium-lithium, the parts are now in satisfactory condition for forming the special fluoridized surface in accordance with the present discovery.
  • the parts are immersingly disposed in an anodizing bath consisting of an aqueous solution of ammonium bifiuoride (NH EHF), 30-45% by Weight. Temperature of the electrolyte is kept below 27 C. during preparation and use. Specific gravity of the correctly prepared solution will be within the range of 1.l651.170 at 24 C.
  • NH EHF ammonium bifiuoride
  • the parts are taken from the electrolytic bath and thoroughly washed in running water to remove every trace of the solution. Finally the, parts are dried by filtered compressed air. Properly processed articles will possess a very uniform, clean, white or pearl gray finish. There will be no signs of attached foundry sand or other foreign matter, and completely free from dark areas indicating deficient anodizing caused, for example, by incomplete removal of precipitated lithium in the case of magnesium-lithium alloys.
  • the anodized coating formed is extremely thin (in order of several millionths of an inch), and can be stripped from the base metal relatively easily without damaging the base metal by the use of a 50% by weight chromic acid solution, for example.
  • a much thicker layer is formed which ranges from 0.00030.002 inch and this layer cannot be removed by chemical stripping techinques without impairing the surface of the base meal. It is possible to remove such coatings from the latter alloys by mechanical means such as vapor honing.
  • the fluoridized coating on the non-lithium magnesium alloys is a separate layer merely adhering in a surface-to-surface manner
  • the coating on lithium alloys comprises a physical change in the surface portions of the base metal itself. That is, in the latter case the anodized surface is substantially integral in a physical sense with the base metal.
  • a resinous outer coating is required. Best results have been obtained where such outer coating is applied in successive layers until the desired thickness is obtained with each layer being dried and cured for that time and temperature peculiar to the particular resin compound.
  • exemplary of satisfactory resinous coating compounds for this purpose are an epoxy-melamine manufactured under the tradename Hysol 4225, and a polyurethane termed Laminar X-500.
  • Example I A 4 x 4 x & inch sheet of magnesium alloy composed of approximately 84.5 percent magnesium, 14.0 percent lithium, 1.0 percent aluminum and 0.5 percent of trace metals and impurities was provided with four (4) circular openings for receiving bolts therethrough.
  • Initial cleaning comprised degreasing in hot perchlorothene vapor.
  • the sample was then introduced into a circulating air oven where it was brought to a temperature of 200 C. and held there for 1 hour.
  • the lithium exudation was removed by rinsing in 60 C. tap Water.
  • Anodizing was accomplished in a 30 percent ammonium bifluoride solution for 45 minutes with an AC current of less than 1 ampere per square foot. After rinsing the anodized sheet was dried by maintaining at 55 C.
  • Example 11 Identical to Example I except the final surface seal was accomplished with Hysol #4225. Testing included immersion in 3% salt solution saturated with magnesium hydroxide (MgOH) for 50 hours. The edges were left unsealed to determine the extent of any lateral movement of corrosion products under the seal. There was no corrosion noted except at the edges and this did not cause substantial peeling of the resin seal. A control panel of the same alloy, but completely unprotected in any way, was subjected to the same test and completely dissolved.
  • MgOH magnesium hydroxide
  • Example 11 Panel and treatment were identical to Example 11 except that the edges were also sealed by the resin. In addition the panel was painted with Space Craft Coating XA194. Immersion in 3% salt solution saturated with MgOH for 72 hours failed to produce any signs of corrosion.
  • an exceptionally tough and durable fluoride anodized coating can be provided on magnesium and its alloys. It is believed that beneficial results flow not only from the use of the special anodizing path, but also particularly with respect to those alloys including lithium the prescribed heating and rinsing immediately prior to anodizing is a salient step in obtaining integration of the anodic coating with the base metal of the character described.
  • fluoride anodizing process comprising: immersing the articles in an aqueous solution consisting essentially of 30-45% ammonium bifluoride;

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
  • Application Of Or Painting With Fluid Materials (AREA)

Description

United States Patent 3,345,276 SURFACE TREATMENT FOR MAGNESIUM- LITHIUM ALLOYS Robert A. Munroe, Candor, N.Y., assignor to International Business Machines Corporation, New York, N.Y., a corporation of New York No Drawing. Filed Dec. 23, 1963, Ser. No. 332,909 2 Claims. (Cl. 20432) The present invention relates broadly to articles of magnesium and its alloys, and more particularly to a special treatment for such articles offering exceptional resistance to corrosion.
Magnesium and magnesium alloys have found wide acceptance as structural materials where there is need for both relatively high strength and light weight. A variety of alloying materials have been added to magnesium in order to improve the mechanical strength properties of substantially pure magnesium. One important class of such alloys are the magnesium-lithium alloys composed of 80% or more by weight of magnesium, and it is with particular reference to these that the invention derives its major area of application.
Magnesium itself has a high resistance to atmospheric corrosion and more resistance to alkali solutions than, say, aluminum. On the other hand, magnesiumis quite vulnerable to attack by most acids with the exception of chromic acids and hydrofluoric acids. With respect to salt spray environments, the resistance against which is a common criterion of choice, magnesium is the most reactive of all the more commonly used structural metals. Alloying various materials, such as lithium, with magnesium increases corrosion resistance from these sources; however, the alloys themselves are subject to deterioration accelerated by the presence of cathodic impurities. Also, it is usually necessary to use mounting or joining means that are constructed of other metals (stainless steel, for example) forming galvanic couples that are quite destructive of the magnesium alloys.
In view of the fact that galvanic couples are almost certain to be encountered in any useful design, special measures must be taken to prevent corrosion from this source. It is felt that organic coatings offer the best present answer to this problem and, as will be seen, their use represents an important aspect of the invention. Before such a coating can be applied to a magnesium alloy article, however, special treatment is necessary to insure a high degree of water resistance, good adhesion of the coating to the metal surface, and flowing of the resinous material into minute crevices of the surface.
One known prior technique for this type of cleaning and surface treating operation is to immerse the articles in hydrofluoric acid. There are, however, practical difficulties with this, in that processing time Varies considerably from the one workpiece to another and is not generally consistent for workpieces of the same geometry. Further, there is no practical way in a production process of determining when cleaning is complete.
A more satisfactory method of surface cleaning or treatment for present purposes is what can be called fluoride anodizing which consists generally of immersing the articles in an ammonium bifluoride solution and with the articles serving as electrodes, apply an alternating current thereto. This cleans in the conventional sense by dissolving and/or loosening surface impurities, and in addition forms a relatively impermeable protective surface layer or coating. An important beneficial adjunct from this process is that surface purification is obtained without materially changing physical dimensions of the workpiece. Exemplary of this advantage in terms of another well-known prior art technique, to insure an equal degree of cleaning effect by more conventional acid ice pickling methods (chromic and mineral acid baths, for example) may require the removal of as much as 0.040 inch of base metal. It is an important aspect of the invention to provide an improved procedure for fluoride anodizing magnesium and magnesium alloy articles.
Exemplary of present known methods of cleaning magnesium alloy articles by fluoride anodizing is that set forth in the United States Patent 2,766,199, William F. Higgins the assignor to Magnesium Elektron Limited, Manchester, England.
It is therefore a primary object of the invention to provide a corrosion resistant surface to magnesium and magnesium alloys which is highly adherent to the metal surfaces and possesses excellent qualities of resistance particularly to electrolytic corrosion.
Another object is the provision of a tightly adherent layer on the metal surfaces by an improved fluoride anodizing process.
Another object is the provision of a corrosion resistant surface as in the above objects which is not destroyed by subsequent heating to elevated temperatures.
Still another object is the applying over the special corrosion resistant surface a resinous sealing coat that is tightly and uninterruptedly adherent thereto and substantially free from included deposits of dirt, moisture and released occluded gases.
Another object of the invention is the provision of a surface treatment for magnesium and its alloys which is highly simplified and readily adapted to production manufacturing.
It is understood that the term magnesium metals" as used here refers not only to substantially pure magnesium, but also to magnesium alloys of all kinds. More particularly, the term relates to magnesium-lithium which has exceptionally desirable physical characteristics, such as mechanical strength and toughness as well as the inherent light weight of magnesium.
Starting with a rough blank workpiece, for example, of a magnesium metal the first step is to remove gross surface dirt, oil, grease and other such materials. This is best accomplished by the well-known process of hot vapor degreasing. By this process the workpiece being treated is exposed to the hot vapor of a material such as perchlorothene for sufficient time to remove surface impurities. Time for removal is usually a matter of minutes at the most. 7
Mill scale can be removed next optionally by either immersion in an appropriate acid solution (10% nitric or sulphuric acids, for example) or by a suitable mechanical technique. The latter can be accomplished by the application of dry pumice or by sanding, choice being dependent on the particular construction of the. workpiece.
Both degreasing and scale removal, although important initial steps to take, are merely cleaning procedures preiiminary to anodizing and if the metal parts or articles are obtained originally in a sufficiently clean form the following procedures may be begun directly.
Because of the relative instability of lithium, those alloys containing lithium require heating treatment prior to anodizing. That is, the magnesium-lithiumarticles are next placed in a circulating air, or inert gas, oven Where they are heated to a temperature that is m the range of ZOO-255 C. for at least one hour. This heating cycle serves to drive out or precipitate lithium from those portions of the alloy closely adjacent the outer surfaces; As will be more fully appreciated later removing the lithium is an important preliminary step to obtaining the special anodized surface of the invention.
After heating, the magnesium-lithium articles or parts are removed from the oven and permitted to cool to room temperature, with the rate of cooling not being (3 critical for present purposes. The cooled articles are immersed in continuously circulating water, which for best results should be heated water not exceeding ap proximately .150 F., and maintained therein for about 5 minutes. This washing operation removes the precipitated lithium from the metal surfaces which if not done would interfere with the subsequent fluoride anodizing.
After cleaning in the above-described manner, and the additional heating step in the case of magnesium-lithium, the parts are now in satisfactory condition for forming the special fluoridized surface in accordance with the present discovery. The parts are immersingly disposed in an anodizing bath consisting of an aqueous solution of ammonium bifiuoride (NH EHF), 30-45% by Weight. Temperature of the electrolyte is kept below 27 C. during preparation and use. Specific gravity of the correctly prepared solution will be within the range of 1.l651.170 at 24 C.
With suitable electrode bars clamped to the parts alternating current is applied in a progressively increasing manner until 110-120 v. AC is reached. Voltage is maintained for 30-35 minutes after current falls to less than 5 a. AC per square foot of the parts surface. Throughout the anodizing a continuous relative movement between the parts and electrolytic solution is provided to maintain the proper temperature indicated above and to prevent localized overheating.
At completion of the anodizing, the parts are taken from the electrolytic bath and thoroughly washed in running water to remove every trace of the solution. Finally the, parts are dried by filtered compressed air. Properly processed articles will possess a very uniform, clean, white or pearl gray finish. There will be no signs of attached foundry sand or other foreign matter, and completely free from dark areas indicating deficient anodizing caused, for example, by incomplete removal of precipitated lithium in the case of magnesium-lithium alloys.
It is important to note the variation in type and character of the fluoridized surface formed by the above process on the different classes of alloys. With respect to those magnesium alloys that do not include lithium, the anodized coating formed is extremely thin (in order of several millionths of an inch), and can be stripped from the base metal relatively easily without damaging the base metal by the use of a 50% by weight chromic acid solution, for example. However, in the case of magnesium-lithium alloys a much thicker layer is formed which ranges from 0.00030.002 inch and this layer cannot be removed by chemical stripping techinques without impairing the surface of the base meal. It is possible to remove such coatings from the latter alloys by mechanical means such as vapor honing.
'Further on this point, whereas the fluoridized coating on the non-lithium magnesium alloys is a separate layer merely adhering in a surface-to-surface manner the coating on lithium alloys comprises a physical change in the surface portions of the base metal itself. That is, in the latter case the anodized surface is substantially integral in a physical sense with the base metal. This can at least be partially explained by the fact that during the special heating step preliminary to anodizing, lithium is removed from the surface portions leaving small crevices or fissures which are filled during anodizing and thereby serve to anchor the coating and base metal together. It is felt, however, that this is not the only effect taking place, but rather there is an apparent penetration and intermingling of'the molecules of the anodic coating with those of the magnesium metal itself forming a substantial region of magnesium fluoride.
For full protection it is generally recognized that a resinous outer coating is required. Best results have been obtained where such outer coating is applied in successive layers until the desired thickness is obtained with each layer being dried and cured for that time and temperature peculiar to the particular resin compound. Exemplary of satisfactory resinous coating compounds for this purpose are an epoxy-melamine manufactured under the tradename Hysol 4225, and a polyurethane termed Laminar X-500.
Many times it is desirable to provide a final coat of a suitable paint, or other finish, over the resinous coating. One such material excellent for this purpose is Space Craft Coating XAl94.
The following specific examples serve to illustrate the invention, but they are not intended to limit it thereto.
Example I A 4 x 4 x & inch sheet of magnesium alloy composed of approximately 84.5 percent magnesium, 14.0 percent lithium, 1.0 percent aluminum and 0.5 percent of trace metals and impurities was provided with four (4) circular openings for receiving bolts therethrough. Initial cleaning comprised degreasing in hot perchlorothene vapor. The sample was then introduced into a circulating air oven where it was brought to a temperature of 200 C. and held there for 1 hour. The lithium exudation was removed by rinsing in 60 C. tap Water. Anodizing was accomplished in a 30 percent ammonium bifluoride solution for 45 minutes with an AC current of less than 1 ampere per square foot. After rinsing the anodized sheet was dried by maintaining at 55 C. for 1 hour, after which it was surface sealed with Laminar X-500 and cured at C. for 1 hour. The seal also included the major surfaces and the edges with a maximum thickness of 0.5 mil. Stainless steel bolts were passed through the openings and nuts tightened thereon to insure good physical contact with the resinous coating. The sample was subjected to a 20% salt spray for 50 hours and no signs of corrosion were in evidence.
Example 11 Identical to Example I except the final surface seal was accomplished with Hysol #4225. Testing included immersion in 3% salt solution saturated with magnesium hydroxide (MgOH) for 50 hours. The edges were left unsealed to determine the extent of any lateral movement of corrosion products under the seal. There was no corrosion noted except at the edges and this did not cause substantial peeling of the resin seal. A control panel of the same alloy, but completely unprotected in any way, was subjected to the same test and completely dissolved.
Example 11] Panel and treatment were identical to Example 11 except that the edges were also sealed by the resin. In addition the panel was painted with Space Craft Coating XA194. Immersion in 3% salt solution saturated with MgOH for 72 hours failed to produce any signs of corrosion.
In accordance with the practice of the invention described here an exceptionally tough and durable fluoride anodized coating can be provided on magnesium and its alloys. It is believed that beneficial results flow not only from the use of the special anodizing path, but also particularly with respect to those alloys including lithium the prescribed heating and rinsing immediately prior to anodizing is a salient step in obtaining integration of the anodic coating with the base metal of the character described.
While the invention has been particularly shown and described with reference to a preferred embodiment thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein Without departing from the spirit and scope of the invention.
What is claimed is:
1. In a fluoride anodizing process for surface treating articles of magnesium lithium alloys, the steps of:
exuding the lithium from those portions of the alloy closely adjacent to the outer surfaces of said articles taminating and non-deteriorating rinse of continu ously circulating water having a temperature maintained below 150 F., the removal of said lithium exudation being maintained for approximately minutes while each of said articles is immersed in said circulating water; and
thereafter treating the articles by a fluoride anodizing process, said fluoride anodizing process comprising: immersing the articles in an aqueous solution consisting essentially of 30-45% ammonium bifluoride;
applying an alternating current voltage to the articles and solution, and progressively increasing said voltage to 110-120 v. AC; and
maintaining the articles in the solution for at least 30 minutes after the current falls to less than 5 amperes per square foot of article surface.
maintained below 150 F., the removal of said lithium exudation being maintained for approximately 5 minutes while each of said articles is immersed in said circulating water;
thereafter immersing the articles in an aqueous solution consisting essentially of 30-45% ammonium bifluoride;
applying an alternating current voltage to the articles and solution, and progressively increasing said voltage to 110-120 v. AC; and
maintaining the articles in the solution for at least 30 minutes after the current falls to less than 5 amperes References Cited UNITED STATES PATENTS per square foot of article surfac 552%? 323? 5:2: 5 2 55? 2. A method of surface treating metal a icl s of m 2428749 10/1947 De u 148 6 2 nesium lithium alloys comprising the Steps 0ft 2459744 1/1949 R ft r g u 318 28 pretreating the articles by a non-contaminating and 2692213 54 117 222 non-deteriorating cle ning pr 2766199 10/1956 Hi g 204 X exuding the lithium from those portion of the l y 2885315 5/1959 -i n 148 20 3 closely adjacent to the outer surface of said articles 2961359 11/1960 -h- 1 by raising and maintaining the temperature of said 16 e a u I articles to a temperature of the range ZOO-255 C 3012917 12/1961 Rlou et a1 117-145 3,032,435 5/1962 Michel 117-7() for at least one hour in a non-contaminating and hnon-deteriorating atmoslpllllere; h JOHN H. MACK, Primary Examiner. t ereafter removing the it ium so exuded from t e surfaces by cooling said articles to room temperature HOWARD WILLIAMS Exammer' and then washing the cooled articles in a non-con- G. KAPLAN, Assistant Examiner.

Claims (1)

  1. 2. A METHOD OF SURFACE TREATING METAL ARTICLES OF MAGNESIUM LITHIUM ALLOYS COMPRISING THE STEPS OF: PRETREATING THE ARTICLES BY A NON-CONTAMINATING AND NON-DETERIORATING CLEANING PROCESS: EXUDING THE LITHIUM FROM THOSE PORTIONS OF THE ALLOY CLOSELY ADJACENT TO THE OUTER SURFACE OF SAID ARTICLES BY RAISING AND MAINTAINING THE TEMPERATURE OF SAID ARTICLES TO A TEMPERATURE OF THE RANGE 200-255*C. FOR AT LEAST ONE HOUR IN A NON-CONTAMINATING AND NON-DETERIORATING ATMOSPHERE: THEREAFTER REMOVING THE LITHIUM SO EXUDED FROM THE SURFACES BY COOLING SAID ARTICLES TO ROOM TEMPERATURE AND THEN WASHING THE COOLED ARTICLES IN A NON-CONTAMINATING AND NON-DETERIORATING RINSE OF CONTINUOUSLY CIRCULATING WATER HAVING A TEMPERATURE MAINTAINED BELOW 150* F., THE REMOVAL OF SAID LITHIUM EXUDATION BEING MAINTAINED FOR APPROXIMATELY 5 MINUTES WHILE EACH OF SAID ARTICLES IS IMMERSED IN SAID CIRCULATING WATER; AND THEREAFTER TREATING THE ARTICLES BY A FLOURIDE ANODIZING PROCESS, SAID FLUORIDE ANODIZING PROCESS COMPRISING: IMMERSING THE ARTICLES IN AN AQUEOUS SOLUTION CONSISTING ESSENTIALLY OF 30-45% AMMONIUM BIFLUORIDE; APPLYING AN ALTERNATING CURRENT VOLTAGE TO THE ARTICLES AND SOLUTION, AND PROGRESSIVELY INCREASING SAID VOLTAGE TO 110-120 V. AC; AND MAINTAINING THE ARTICLES IN THE SOLUTION FOR AT LEAST 30 MINUTES AFTER THE CURRENT FALLS TO THE LESS THAN 5 AMPERES PER SQUARE FOOT OF ARTICLE SURFACE.
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Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5240589A (en) * 1991-02-26 1993-08-31 Technology Applications Group, Inc. Two-step chemical/electrochemical process for coating magnesium alloys
WO1996028591A1 (en) * 1995-03-13 1996-09-19 Magnesium Technology Limited Anodisation of magnesium and magnesium based alloys
US6797147B2 (en) 2001-10-02 2004-09-28 Henkel Kommanditgesellschaft Auf Aktien Light metal anodization
US20050061680A1 (en) * 2001-10-02 2005-03-24 Dolan Shawn E. Article of manufacture and process for anodically coating aluminum and/or titanium with ceramic oxides
US20050115839A1 (en) * 2001-10-02 2005-06-02 Dolan Shawn E. Anodized coating over aluminum and aluminum alloy coated substrates and coated articles
US20050115840A1 (en) * 2001-10-02 2005-06-02 Dolan Shawn E. Article of manufacture and process for anodically coating an aluminum substrate with ceramic oxides prior to polytetrafluoroethylene or silicone coating
US20060013986A1 (en) * 2001-10-02 2006-01-19 Dolan Shawn E Article of manufacture and process for anodically coating an aluminum substrate with ceramic oxides prior to organic or inorganic coating
US20070144914A1 (en) * 2000-05-06 2007-06-28 Mattias Schweinsberg Electrochemically Produced Layers for Corrosion Protection or as a Primer
US9701177B2 (en) 2009-04-02 2017-07-11 Henkel Ag & Co. Kgaa Ceramic coated automotive heat exchanger components
EP4053309A1 (en) * 2021-03-01 2022-09-07 Canon Kabushiki Kaisha Alloy member, sliding member, apparatus, and method for manufacturing alloy member

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US2332487A (en) * 1938-11-14 1943-10-19 Dow Chemical Co Surface treatment for articles of magnesium and alloys thereof
US2428749A (en) * 1944-08-19 1947-10-07 Dow Chemical Co Surface treatment of magnesium alloys
US2459744A (en) * 1944-12-18 1949-01-18 Firestone Tire & Rubber Co Adhesion of rubber to magnesium
US2692213A (en) * 1951-04-11 1954-10-19 Chicago Dev Corp Electrical conductor
US2766199A (en) * 1951-07-04 1956-10-09 Magnesium Elektron Ltd Cleaning of magnesium base alloy castings
US2885315A (en) * 1958-03-26 1959-05-05 Aluminum Co Of America Process of treating magnesium-bearing aluminum base alloys with boron trifluoride
US2961359A (en) * 1957-09-12 1960-11-22 Gen Electric Hydrided lithium-magnesium alloys and method
US3012917A (en) * 1957-03-26 1961-12-12 Pechiney Prod Chimiques Sa Method of protecting metal surfaces
US3032435A (en) * 1958-07-17 1962-05-01 Knapsack Greisheim Ag Process for improving the corrosion resistance of pieces of light metals and light metal alloys

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1574289A (en) * 1923-01-22 1926-02-23 American Magnesium Corp Protective coating for magnesium
US2332487A (en) * 1938-11-14 1943-10-19 Dow Chemical Co Surface treatment for articles of magnesium and alloys thereof
US2428749A (en) * 1944-08-19 1947-10-07 Dow Chemical Co Surface treatment of magnesium alloys
US2459744A (en) * 1944-12-18 1949-01-18 Firestone Tire & Rubber Co Adhesion of rubber to magnesium
US2692213A (en) * 1951-04-11 1954-10-19 Chicago Dev Corp Electrical conductor
US2766199A (en) * 1951-07-04 1956-10-09 Magnesium Elektron Ltd Cleaning of magnesium base alloy castings
US3012917A (en) * 1957-03-26 1961-12-12 Pechiney Prod Chimiques Sa Method of protecting metal surfaces
US2961359A (en) * 1957-09-12 1960-11-22 Gen Electric Hydrided lithium-magnesium alloys and method
US2885315A (en) * 1958-03-26 1959-05-05 Aluminum Co Of America Process of treating magnesium-bearing aluminum base alloys with boron trifluoride
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US5240589A (en) * 1991-02-26 1993-08-31 Technology Applications Group, Inc. Two-step chemical/electrochemical process for coating magnesium alloys
WO1996028591A1 (en) * 1995-03-13 1996-09-19 Magnesium Technology Limited Anodisation of magnesium and magnesium based alloys
US5792335A (en) * 1995-03-13 1998-08-11 Magnesium Technology Limited Anodization of magnesium and magnesium based alloys
US6280598B1 (en) 1995-03-13 2001-08-28 Magnesium Technology Limited Anodization of magnesium and magnesium based alloys
US20070144914A1 (en) * 2000-05-06 2007-06-28 Mattias Schweinsberg Electrochemically Produced Layers for Corrosion Protection or as a Primer
US20050061680A1 (en) * 2001-10-02 2005-03-24 Dolan Shawn E. Article of manufacture and process for anodically coating aluminum and/or titanium with ceramic oxides
US7569132B2 (en) 2001-10-02 2009-08-04 Henkel Kgaa Process for anodically coating an aluminum substrate with ceramic oxides prior to polytetrafluoroethylene or silicone coating
US20050115840A1 (en) * 2001-10-02 2005-06-02 Dolan Shawn E. Article of manufacture and process for anodically coating an aluminum substrate with ceramic oxides prior to polytetrafluoroethylene or silicone coating
US6916414B2 (en) 2001-10-02 2005-07-12 Henkel Kommanditgesellschaft Auf Aktien Light metal anodization
US20060013986A1 (en) * 2001-10-02 2006-01-19 Dolan Shawn E Article of manufacture and process for anodically coating an aluminum substrate with ceramic oxides prior to organic or inorganic coating
US6797147B2 (en) 2001-10-02 2004-09-28 Henkel Kommanditgesellschaft Auf Aktien Light metal anodization
US7452454B2 (en) 2001-10-02 2008-11-18 Henkel Kgaa Anodized coating over aluminum and aluminum alloy coated substrates
US20050115839A1 (en) * 2001-10-02 2005-06-02 Dolan Shawn E. Anodized coating over aluminum and aluminum alloy coated substrates and coated articles
US7578921B2 (en) 2001-10-02 2009-08-25 Henkel Kgaa Process for anodically coating aluminum and/or titanium with ceramic oxides
US20100000870A1 (en) * 2001-10-02 2010-01-07 Henkel Ag & Co. Kgaa Article of manufacture and process for anodically coating aluminum and/or titanium with ceramic oxides
US7820300B2 (en) 2001-10-02 2010-10-26 Henkel Ag & Co. Kgaa Article of manufacture and process for anodically coating an aluminum substrate with ceramic oxides prior to organic or inorganic coating
US8361630B2 (en) 2001-10-02 2013-01-29 Henkel Ag & Co. Kgaa Article of manufacture and process for anodically coating an aluminum substrate with ceramic oxides prior to polytetrafluoroethylene or silicone coating
US8663807B2 (en) 2001-10-02 2014-03-04 Henkel Ag & Co. Kgaa Article of manufacture and process for anodically coating aluminum and/or titanium with ceramic oxides
US9023481B2 (en) 2001-10-02 2015-05-05 Henkel Ag & Co. Kgaa Anodized coating over aluminum and aluminum alloy coated substrates and coated articles
US9701177B2 (en) 2009-04-02 2017-07-11 Henkel Ag & Co. Kgaa Ceramic coated automotive heat exchanger components
EP4053309A1 (en) * 2021-03-01 2022-09-07 Canon Kabushiki Kaisha Alloy member, sliding member, apparatus, and method for manufacturing alloy member

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