Classifications

• • 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
  • C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
  • C23C22/05—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions
  • C23C22/06—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6
  • C23C22/24—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6 containing hexavalent chromium compounds
  • C23C22/33—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6 containing hexavalent chromium compounds containing also phosphates
• • 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
  • C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
  • C23C22/05—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions
  • C23C22/06—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6
  • C23C22/07—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6 containing phosphates

Definitions

• Another prior method comprises the step of passing a galvanized steel strip through a nickel salt solution which must be maintained at a high temperature, but this method has the disadvantage that the resulting black nickel oxide coating rubs off easily so that it is necessary to provide an additional coating of lacquer to protect it. Also, when this method is carried on with the metal strip moving at high speeds, a uniform coating cannot be insured and there are resulting bare spots where the metal is protected only by the zinc coating provided by the galvanizing process. In general, prior color coatings have had the disadvantage that there has been no chemical union between the coating and the metal base.
• the chromate films which are thus deposited are generally noncrystalline, nonporous and gel-like. They are quite susceptible to being damaged by abrasion immediately after being formed and should, therefore, be allowed to age from twelve to twenty-four hours before being subjected to normal handling operations in the shop. When the chromate coatings are applied by electrolytic methods these precautions need not be taken.
• the chromate films which give maximum protection are those which contain both trivalent and hexavalent chromium.
• the nonporous nature of the film enables it to exclude moisture from the metal to a very great extent and, if there are any discontinuities in the film, the hexavalent chromium, being slightly soluble, exerts a well known inhibiting action. It has been found that the formation of the undesirable white corrosion product is inhibited as long as there is a small amount of hexavalent chromium in the film.
• chromate coatings have found. wide industrial use, it appears that, because of the above mentioned liability to abrasion, they have been employed only on parts which are substantially static when. in use as distinguished from moving parts and parts having contact with each other or with other members, such as continuously moving metal strips which are acted upon during their movement by forming or shearing members. Furthermore, chromate coatings cannot be applied by continuous strip processes since the coating being gel-like would be readily removed by the strip feeding mechanism immediately after formation and before it had an opportunity to age.
• Another object of the invention is to provide improved coatings for base metals which are substantially colorless and transparent whereby to leave unimpaired the desirable surface characteristics of the base metal while providin g a maximum protection therefor.
• Yet another object of the invention is to provide coating methods and baths which can apply protective coatings of the type set forth to the surfaces of coating metals such as zinc with substantially less depletion of the zinc as compared with prior coating methods and baths.
• Still another object of the invention is to provide protective coatings of the type set forth which are more readily colored to provide pleasing and durable colored protective coatings.
• Yet another object of the invention is to provide a proved coatings formed of a combination of protective compounds and coating methods which can deposit these combinations of protective compounds simultaneously in a one step process.
• Yet another object of the invention is to provide a galvanized steel strip having a black coating which is chemically united with the zinc and thereby tightly bonded thereto, the color coating being uniformly and evenly distributed so that there are no bare spots and no additional protective coating is required.
• Still another object of the invention is to provide an improved method of applying a black coating to base metal surfaces in which the coating is effected by immersing the base metal in a coating solution at room temperature, thereby avoiding the necessity of providing the expensive heating equipment which has been required when coating with prior compounds such as nickel salts and the like.
• a composition containing an anion of a phosphoric acid ester of cyclohexanol distributed in a suitable carrier is the anion of a phosphoric ester of hexahydroxycyclohexane (inositol), the preferred material being the anion of inositol hexaphosphoric acid commonly called phytic acid. It also has been found that these compounds may be applied as the free acid or as a salt thereof, the sodium, potassium, calcium and magnesium salts being particularly advantageous.
• a preferred class of carriers useful in the present invention are hydrophilic carriers.
• aqueous solutions, oil-water emulsions and wax-like compositions containing water and other hydrophilic materials can be used satisfactorily.
• any base metal which will react with an acid medium or with a basic medium can be treated successfully to provide a protective coating thereon using this invention.
• the coating composition is of an acid character, the pH may be from about 0.8 to about 6.0.
• Substantially all materials on which the present invention is useful can be treated with such coating compositions.
• Certain metals such as zinc, cadmium, aluminum and magnesium can also be successfully treated when the coating composition is basic in character. More particularly such compositions are useful when they have a pH of about 7.5 to about 9.0 or
• the concentration of the phytic acid or other related coating material used in the present invention is preferably present in the carrier in a concentration of from about 0.001 mole per liter to about 0.1 mole per liter.
• the chromate may have a concentration of from about 0.1 to 1.0 mole per liter of coating composition.
• the time for obtaining a satisfactory coating may be from a fraction of a second up to as much as 30 minutes or an hour or more.
• Example 10 A clean strip of mild carbon steel was provided.
• a coating composition was prepared by adding to water an aqueous solution of phytic acid containing 70% by weight of free phytic acid to provide a concentration in the coating solution of about 0.1% by weight .of phytic acid.
• Example 1 The method of Example 1 above has been operated successfully when the concentration of phytic acid in the coating solution is increased to as much as 0.2% by weight. Smaller concentrations of phytic aoidcan also be used but resulted in coatings of less weight per square foot for like exposure times. It further was found that the pH of the coating solution could be varied from approximately 1.2 to approximately 1.7 and still provide satisfactory coatings with the same exposure time.
• Example 2 A clean zinc surface was provided.
• a coating solution was made by adding an aqueous phytic acid solution containing 70% phytic acid by weight to water to provide a concentration therein of 0.1% by weight of phytic acid. Sufficient 1 N sodium hydroxide solution in water was added to provide a pH of 3.6 in the coating solution. The zinc surface was then immersed in the coating solution for ten seconds. Thereafter the zinc surface was removed from the solution and dried. It was found that a zinc phytate coating had been formed on the zinc surface. The coating was substantially colorless, provided good paint adhesion and gave good corrosion protection against humidity and salt water as determined by standard corrosion tests.
• the coating solution gave satisfactory coatings when the phytic acid concentration therein was increased to 0.2% by weight or more. Satisfactory coatings were also obtained when the pH was adjusted between about 3.5 and 3.8.
• Example 3 The coating solution and method described above in Example 2 with respect to a zinc surface was also carried out on a cadmium surface. A protective coating was formed on cadmium which was substantially colorless, had good paint adhesion qualities, and provided excellent protection against corrosion by humidity and salt water.
• suitable protective coatings can be formed utilizing salts of phytic acid.
• the coating solution or bath may utilize a carrier other than water and may be basic instead of acidic in pH.
• the following is an example of the use of sodium phytate in an oil-water emulsion to provide protective coatings on base metals.
• Example 4 A roll forming oil was provided which was an emulsion of oil and water. A solution of sodium phytate in water was formed, the concentration of the sodium phytate being 25% by weight. 15 cc. of the sodium phytate solution were added to one gallon of roll forming oil. The resultant coating composition had a pH of 8.0. Galva nized steel plate was then roll formed utilizing the protective coating solution in the same way that the roll forming oil had been used heretofore. In the roll forming operation, portions of the galvanized steel sheet were folded to angles less than 90 whereby to thin and in certain instances rupture the protective galvanized surface to expose the bare steel therebeneath. The roll forming oil provided a protective coating on both the galvanized surface and on the exposed steel surfaces which protected the roll formed piece from corrosion when exposed to high humidity conditions and salt water. Satisfactory operation was obtained at any pH between about 7.5 and 8.7.
• any of the base metals that react with acidic or basic mediums or solutions can be coated using the above coating solutions.
• the coating solution may contain for example from about 0.001 mole per liter of phytate ion (empirical formula C H O P to about 0.003 mole per liter or more.
• concentrations are used in an acid solution, the immersion time will be in the order of ten seconds to provide an adequate protective phytate coating.
• concentration of phytate is lowered, the amount of coating laid down during a given unit of time will be less.
• concentration of phytate ion is increased, a heavier coating of phytate will be formed on the metal during a given period of time.
• the amount of coating laid down per unit of time is less if the pH is raised and is greater if the pH is lowered.
• the amount of coating produced during a given unit of time is less when the pH is lowered and greater when the pH is raised.
• the phytate coating and to color the coating in a single process step.
• This can be readily done in one form of the invention by adding a suitable organic dye to the coating solutions of Examples 1, 2 and 3 above.
• a suitable organic dye for example it has been found that alizarine dyes can be conveniently incorporated therein. Suitable results were obtained when 0.02 gm. of alizarine red was added per liter of the coating solution of any of Examples 1, 2 and 3 above.
• the coatings were uniformly colored using the same coating method described. The colors were deep and were retained in the coatings.
• Copper sulfate CuSO 3 Phytic acid (C H O (H PO 2 Ferrous ammonium sulfate (Fe(NH (SO 1 Citric acid (C HgOqHzO) 1 Alizarine red 0.2
• the metal surface to be coated was immersed in the coating solution for 10 seconds.
• the resultant coating was continuous, closely adherent and colored deep black. The black color was also adherent.
• the proportions set forth above may be varied. However, preferably the molecular ratio between the copper sulfate and the phytic acid should be approximately 1 part of phytic acid to 6 parts of copper sulfate. As a greater proportion of copper sulfate is provided relative to the phytic acid, the coating forms more slowly and is not as adherent as that of the example set forth above. Conversely if the proportion of phytic acid is increased relative to the copper sulfate, there is a gradual loss of coloring.
• One particularly useful application of the coating solution and method of Example 5 is to apply it to 6 the coating of galvauized'steel strap. 'In such a case it is convenient to apply the coating by running the strap endwise through the coating solution.
• the pH is maintained within the range of about 3.7 to about 4.3 to obtain best results.
• the copper from the copper sulfate is believed to be deposited on the galvanized steel strip as finely divided particles of metallic copper which have a black color.
• a copper deposit may be effected by the immersion of a galvanized steel strip in an aqueous copper sulfate solution with no other ingredients present but, of course, in the absence of other ingredients, the copper does not adhere to the metal strip and may be readily wiped off.
• the copper sulfate provides the strip with the black pigment which is believed to be finely divided copper.
• the phytic acid reacts with the zinc of the galvanized strip to produce zinc phytate which adheres to the galvanized surface and provides a protection therefor.
• This zinc phytate coating does not wipe ofl' and it serves to bond the black copper deposit to the zinc surface.
• the color of the coating tends toward that of ordinary red copper provided the galvanizing coating has been sufficiently thin to be removed by the action of the copper sulfate; but, if the zinc coating is so thick that it is not removed by the action of the copper sulfate, the color will remain black but may be readily wiped off due to the lack of adequate bonding because of insufiicient phytic acid.
• ferrous ammonium sulfate deepens the color of the coating.
• the alizarine red also serves to deepen the color of the coating and to make it more uniform. It removes streaks and may be termed a color leveler.
• Citric acid is added to the solution to act as a buffer and to maintain the pH of the solution constant.
• the control of the pH is necessary to maintain the desired performance of the bath and the quality of the deposits.
• the preferred range Within which the pH is maintained, as indicated above, has been determined empirically by adjusting the pH and observing the results.
• the phytate coating can be formed simultaneously with other coatings on the base metal.
• the co-formation of a phytate and chromate coating on a zinc surface such as a galvanized steel surface can be conveniently carried out by running a strip of the metal through a coating bath at a temperature of 75 F., the bath having a phytate concentration of 0.02 mole per liter and having a dichromate concentration of 0.4 mole per liter, the pH of the solution being adjusted to between about 1.8, the strip being in the bath for approximately 7 eight seconds.
• the following is an example of the manner in which the above proportions can be obtained and a specific example of the manner of carrying out the method of the coating.
• Example 6 The following ingredients are added in the amounts indicated to sufficient water to form one gallon of coating solution:
• Potassium dichromate K Cr O pound l Sulfuric acid (H 80 grams 12 acid (C6I'I606(H2PO3)6)
• Other sources of chromate ion can be used besides potassium dichromate.
• sodium dichromate, chromic acid, other salts of chromic acid, etc. can be used in place of potassium dichromate.
• Other acids and particularly mineral acids may be used in the place of the sulfuric acid of the above coating solution.
• the improved process As an example of the use of the improved process, it was employed in the treatment of steel strip having a width of 2 inches and a thickness of 0.011 inch which was galvanized on both sides to a thickness of 0.00004 inch.
• This galvanized strip was then run through a bath of the coating solution having a temperature of 75 Fahrenheit. The solution was not heated and the process may be carried on at room temperature.
• the metal strip was in continuous motion through the bath at a speed of about 8 feet per minute and each portion of the strip was immersed in the bath for a period of approximately 8 seconds.
• the result of using, the improved bath of Example 6 is the production of a combination zinc phytate and zinc chromate coating on the galvanized steel with the typical yellow chromate discoloring practically eliminated.
• the coating also has a relatively high resistance to abrasion as compared to former chromate coatings. Any yellow color in the coating may be diminished by shortening the immersion time which also results in a thinner coating.
• the yellow coloration of the coating is substantially less than that of a chromate coating alone.
• the coating furthermore is flat in lustre and exhibits substantially no iridescence.
• the coating made according to Example 6 further has been found to be capable of receiving and retaining dyes whereby to provide colored coatings.
• the dye can be applied by simply running the coated metal through an aqueous solution of the dye as for example 0.2 gm. per
• a further advantage of the phytate-chromate coating made by following Example 6 above is the fact that the coating is firm and hard whereby to be resistant to abrasion immediately after the formation thereof. This contrasts sharply with coatings formed of chromate alone which are generally noncrystalline, nonporous, and gellike. Such coatings are extremely susceptible to damage from abrasion immediately following formation and must be aged 12 to 24 hours before being subjected to normal shop handling.
• Example 7 The coating solution and method of Example 6 were applied in an identical manner to cadmium plated steel plates. The coatings formed possessed all of the desirable characteristics above with respect to the similar coatings on zinc in Example 6.
• Example 6 instead of the potassium dichromate utilized in Example 6 it is possible to use other sources of chromate ion such as sodium dichromate as has been discussed above. Furthermore, it is possible to utilize other acids in place of the sulfuric acid such for example as nitric acid. The following is an example of the manner of forming and using such a coating solution whereby to provide 0.55 mole per liter of dichromate and 0.012 mole per liter of pyh-tate in the coating solution.
• Example 8 120 pounds of sodium dichrorn ate were dissolved in 25 gallons of water. To this solution was added 5 gallons of phytic acid (70% free p-hytic acid by weight in water). 10 gallons of nitric acid (70%) were then slowly metered into the solution, the solution being continually stirred and cooled to hold the temperature below 110 F. Thereafter sui'licient water was added to make a total of gallons. This concentrated solution was thereafter diluted with 20 times its volume of water to provide a total of 1,000 gallons of coating solution.
• the solution was heated to a temperature of 100 F. and maintained at that temperature :5 F. during the coating operation.
• the pH was maintained at about 0.9 to about 1.3 during the coating operation.
• the pH should not be permitted to rise above 113 since the solution becomes buffered above that pH and large quantities of nitric acid are therefore needed to bring the pH down to a suitable operating point.
• the zinc concentration in the solution has reached approximately 12 gm. per liter, the solution is no longer'useful to pro- 7 vide a suitable phytate-chromate coating.
• a galvanized steel strip was then fed into and through the solution at a rate such that it was exposed to the solution for ten seconds;
• the combination zinc phytate-zinc chromate coating formed possessed all of the desirable characteristics'set forth above with respect to Example 6.
• Example 9 The coating solution of Example 8 was applied to a Example 11 A tin plated steel strip was coated using the coating solution and coating method of Example 8. The resultant tin phytate-tin chromate coating was not readily disccrnible by visual inspection. The coating, however, gave good protection against corrosion as determined by humidity and salt water exposure tests.
• a hydrophilic wax-like base or carrier has been successfully used in applying a phytate coating to aluminum metal.
• the following is a specific example of a suitable coating composition utilizing a hydrophilic wax-like base.
• Example 12 The following ingredients were mixed in the proportions indicated:
• the rate of coating can be increased by rapidly flowing the coating solution about the article to be coated.
• the following is a specific example of such a method.
• Example 13 A coating solution as prepared above in Example 8 was diluted with an equal amount of water. The result-ant coating solution was then pumped rapidly through a chamber 4 inches long through which a galvanized steel strip was passed at a rate of 100 feet per minute. The zinc surface was found to be coated with a zinc phytate-zinc chroma-re coating possessing all of the desirable characteristics set forth above with respect to Example 6. The length of contact of the coating solutionwith the Zinc surface being coated was only a fraction of a second.
• the phytic acid used was an aqueous solution containing approximately 70% by weight of phytic acid in a relatively pure state. It has been found, however, that it is not necessary to use substantially pure phytic acid and in fact waste solutions or concentrated waste solutions resulting from the steeping of grains called steep liquor is sufficiently rich in phytic acid to work satisfactorily. These liquors contain about -13% phytic acid by weight. The other 10 impurities found therein also do not interfere with the coating reactions.
• a coating composition to provide a protective coating on base metals said composition being a paste comprising about 0.001 to about 0.1 mole per liter of phytate ion dispersed in a wax-like hydrophilic base, said composition having a pH in the range from about 2.5 to about 2.8.
• a coating composition to provide a protective coating on base metals comprising about 0.001 to about 0.1 mole per liter of phytate ion dispersed in an oil-water emulsion, said composition having a pH in the range from about 7.5 to about 8.7.
• a coating composition to provide a protective coating on base metals comprising an aqueous solution having a pH in the range from about 0.8 to about 6.0 and containing from about 0.001 to about 0.1 mole per liter of phytate ion and copper sulfate in sufiicient concentration to impart a black color to metal contacted by the solution, the ratio of copper ion to phytate ion in said solution being about 6.
• a coating composition to provide a protective coating on base metals comprising from about 0.001 to about 0.1 mole per liter of phytate ion and from about 0.1 to about 1.0 mole per liter of a salt of chromic acid dispersed in an acidic carrier, said composition having a pH in the range from about 0.8 to about 6.0.
• a coating composition to provide a protective coating on base metals comprising from about 0.001 to about 0.1 mole per liter of phytate ion and from about 0.1 to about 1.0 mole per liter of chromate ion dispersed in an acidic carrier, said composition having a pH in the range from about 0.8 to about 6.0
• a coating composition to provide a protective coating on base metals comprising a wax-like acidic hydrophilic base having a pH in the range from about 0.8 to about 6.0 and containing from about 0.001 to about 0.1 mole per liter of phytate ion and from. about 0.1 to about 1.0 mole per liter of chromate ion.
• a bath for the coating of metal by immersion comprising an aqueous solution containing about 0.001 to about 0.1 mole per liter of phytic acid, ferrous ammonium sulfate, copper sulfate, the molar ratio of copper sulfate to phytic acid being about 6, and a bufier to maintain the pH of the bath in the range from about 3.7 to about 4.3.
• a bath for the coating of metal comprising an aqueous solution of the following ingredients in the following proportions per liter of solution: three grams of copper sulfate, two grams of phytic acid, one gram of ferrous ammonium sulfate, one gram of citric acid and twotenths of a gram of alizarine red.
• a bath for the coating of metal by immersion consisting essentially of an aqueous solution containing a salt of chromic acid, a mineral acid and phytate ion, said salt of chromic acid being present in an amount equivalent to approximately one pound of potassium dichromate per gallon of solution and said phytate ion being present in an amount equivalent to approximately fifty grams of phytic acid per gallon of solution.
• the method of providing a protective coating on base metals comprising applying to the base metal a coating composition including from about 0.001 to about 0.1 mole per liter of phytate ion dispersed in an hydrophilic carrier, composition having a pH in the range from about 0.8 to about 9.0.
• the method of providing a protective coating on base metals comprising immersing the base metal in a coating composition comprising an aqueous solution containing about 0.001 to about 0.1 mole per liter of phytate ion, said composition having a pH in the range from about 0.8 to about 9.0.
• the method of providing a protective coating on base metals comprising spreading a wax-like hydrophilic base having a pH in the range from about 0.8 to about 9.0 containing from about 0.001 to about 0.1 mole per liter of phytate ion on the base metal, and thereafter removing the excess base.
• the method of providing a protective coating .on base metals comprising applying to the base metal an oil-water emulsion having a pH in the range from about 0.8 to about 9.0 and containing from about 0.001 to about 0.1 mole per liter of phytate ion.
• the method of providing a protective coating on base metals comprising applying to the base metal a coating composition including an acidic hydrophilic carrier havin a pH in the range from about 0.8 to about 6.0
• the method of providing a protective coating on base metals comprising applying to the base metal a coating composition including an acidic hydrophilic carrier having a pH in the range from about 0.8 to about 6.0 and containing from about 0.001 to about 0.1 mole per liter of phytate ion and an inorganic pigment in sufficient amount to impart a predetermined color to metal contacted by said carrier.
• the method of providing a protective coating on base metals comprising applying to the base metal a coating composition including an acidic hydrophilic carrier having a pH in the range from about 0.8 to about 6.0 and containing from about 0.001 to about 0.1 mole per liter of phytate ion and an organic dye in sufiicient amount to impart a predetermined color to metal contacted by said carrier.
• the method of providing a protective coating on base metals comprising applying to the base metal a coating composition including an acidic hydrophilic carrier having a pH in the range from about 0.8 to about 6.0 and containing from about 0.001 to about 0.1 mole per liter of phytate ion and copper sulfate in sufiicient amount to impart a predetermined black color to metal contacted by said carrier, the molar ratio of copper sulfate to phytate ion being about 6.
• the method of providing a protective coating on base metals comprising applying to the base metal a coating composition including an acidic hydrophilic carrier having a pH in the range from about 0.8 to- 6.0 and containing from about 0.001 to about 0.1 per liter of phytate ion and from about 0.1 to about 1.0 mole per liter of a salt of chromic acid.
• the method of providing a protective coating on base metals comprising applying to the base metal a coating composition including an acidic hydrophilic carrier having a pH in the range from about 0.8 to about 6. and containing about 0.001 to about 0.1 mole per liter of phytate ion and from about 0.1 to about 1.0 mole per liter of chromate ion.
• the method of providing a protective coating on base meta-ls comprising applying to the base metal a coating composition including a wax-like acidic hydrophilic base containing about 0.001 to about 0.1 mole per liter of pyhtate ion and from about 0.1 to about 1.0 mole per liter of chromate ion and having a pH in the range from about 0.8 to about 9.0, and thereafiter removing the excess of said coating composition.
• the method ct coating a galvanized steel strip 12 which consists in immersing the strip in an aqueous solution containing copper sulfate, phytic acid, and ferrous ammonium sulfate, said copper sulfate being present in a concentration of about three grams per liter of solution and said phytic acid being present in a concentration of about two grams per liter of solution.
• the method of coating a galvanized steel strip which consists in immersing the strip in an aqueous solution of the following ingredients in the following amounts: three grams of copper sulfate, two grams of phytic acid, one gram of ferrous ammonium sulfate, one gram of citric acid and two-tenths of a gram of alizarine red.
• the method of coating a galvanized or cadmium plated steel strip which consists in immersing the strip in an acidic aqueous solution having a pH in the range from about 0.8 to about 6.0 and containing from about 0.1 to about 1.0 mole per liter of a salt of chromic acid, a mineral acid, and from about 0.001 to about 0.1 mole per liter of phytate ion.
• the method of coating a galvanized or cadmium plated steel strip which consists in immersing the strip in an aqueous solution having a pH in the range from about 0.8 to about 6.0 and containing from about 0.1 to about 1.0 mole per liter of potassium dichromate, sulfuric acid, and from about 0.001 to about 0.1 mole per liter of phytic acid.
• a base metal having a protective coating thereon comprising a phytate compound of the base metal.
• a base metal having a protective coating thereon comprising a phytate compound of the base metal and a coloring agent sufficient to impart a predetermined color to the metal.
• a base metal having a protective coating thereon comprising a phytate compound of the base metal and black colloidal displacement copper dispersed in said coating.
• a copper containing base metal having a protective coating thereon comprising copper phytate.
• An iron containing base metal having a protective coating thereon comprising iron phytate.
• a zinc containing base metal having a protective coating thereon comprising zinc phytate.
• An aluminum containing base metal having a protective coating thereon comprising aluminum phytate.
• a tin containing base metal having a protective coating thereon comprising tin phytate.
• a base metal having a protective coating thereon comprising a phytate compound of the base metal and a compound of the base metal with an anion consisting of chromium and oxygen.
• a base metal having a protective coating thereon comprising a phytate compound of the base'metal and a chromate compound of thebase metal.
• a zinc containing metal member having a coating comprising zinc chromate and zinc phytate.
• a cadmium containing metal member having a coating comprising cadmium chromate and cadmium phytate.
• a copper containing metal member having a coating thereon comprising copper chromate and copper phytate.
• An aluminum containing metal member having a coating thereon comprising aluminum chromate and aluminum phytate.
• a tin containing metal member having a coating thereon comprising tin chromate and tin phytate.
• a composition for use in providing a protective coating on base metals comprising essentially a mixture of a first compound selected from the class consisting of phytic acid and salts thereof and a second compound, said second compound being a copper salt, the molar ratio of said second compound to said first compound being about 6.
• a composition for use in providing a protective coating on base metals comprising essentially a mixture of a first compound selected from the class consisting of phytic acid and salts thereof and a second compound from the class consisting of chromic acid and salts thereof, said first and second compounds being present in amounts equivalent to from about 0.001 to about 0.1 mole of the first compound and from about 0.2 to about 0.6 mole of the second compound.
• a composition for use in providing a protective coating on base metals comprising essentially a mixture of a first compound selected from the class consisting of phytic acid and salts thereof and a second compound from the class consisting of dichromic acid and salts thereof, said first and second compounds being present in amounts equivalent to from about 0.001 to about 0.1 mole of the first compound and from about 0.2 to about 0.6 mole of the second compound.

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• 1958
  • 1958-03-31 US US72479458 patent/US3007818A/en not_active Expired - Lifetime
• 1960
  • 1960-12-15 GB GB43174/60A patent/GB906900A/en not_active Expired
  • 1960-12-15 BE BE598203A patent/BE598203A/fr unknown
  • 1960-12-15 LU LU39541D patent/LU39541A1/xx unknown

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