Unlted States Patent [19] [11] Patent Number: 4,539,051 Hacias [45] Date of Patent: Sep. 3, 1985

[S4] PROCESS FOR PRODUCING PHOSPHATE 4,497,666 2/1985 Schapira et al...... 148/615 R COATINGS Primary Examiner~Thurman K. Page [75] Inventor: Kenneth J. Hacias, Sterling Heights, Attorney, Agent, 01‘ Fl'rm—Arthur E. Kluegel . M‘Ch- [57] ABSTRACT [73] Asslgnee: Parker Chewical Company’ Madlson An improved process for activating metal surfaces prior Helghts’ Mlch‘ to a phosphating treatment whereby relatively thin, [21] Appl. No.: 690,431 dense, ?ne-sized and uniform crystalline adherent phos [22] Filed: Jan. 10, 1985 phate coatings are produced providing superior corro slon protection and paint adherence when coated sub Related Us. Application Data strates are subjected to cyclical temperature and ‘ambi ent environments typifying normal service conditions. [63] Continuation-impart of Ser. No. 469,621, Mar. 2, 1983, To prepare the aqueous activating Solution, a dry acti abandoned" vating composition is prepared which is adapted to be [51] Int. Cl.3 ...... C23C 1/10; CZSD 13/00 dispersed in Water at a controlled concentration and [52] US. Cl...... 148/615 Z; 148/615 R; which comprises a mixture of about 60 to about 90% by 204/1813; 427/4195; 427/4197 weight of a particulated dried reaction product of a [58] Field of Search ...... 148/615 Z, 6.15 R; titanium-containing compound and sodium phosphate 204/181 R, 131 C, 469, 621; 427/409, 419-5, compound containing at least about 0.005% by weight 419-7 titanium with the balance comprising tetrasodium pyro [56] References Cited phosphate. The dry activating composition is dispersed in the aqueous solution to provide a total concentration U.S. PATENT DOCUMENTS of from about 0.1 to about 10 g/l. In accordance with 2,310,239 2/1943 Jernstedt ...... 148/6 the process aspects of the present invention, the aqueous 2,874,081 2/1959 Cavanagh et a1. . . 148/6115 dispersion containing the activating composition is ap 3,222,226 12/1965 Maurer et a]...... 148/616 plied to cleaned metal surfaces such as steel, zinc and 3,279,958 l0/l966 Maurer et al. .. 148/616 aluminum before the following zinc phosphating step 3,664,887 5/1972 Atkiss ...... 148/616 4,110,129 8/1978 Matsushima et a1. . 148/615 R whereby improved phosphating coatings are produced. 4,152,170 5/1979 Guhde ...... 148/615 R 4,165,242 8/1979 Kelly et a1...... 148/615 Z 27 Claims, N0 Drawings 4,539,051 1 2 tration for activating metal surfaces for subsequent re PROCESS FOR PRODUCING PHOSPHATE action with a high-zinc phosphate coating solution to COATINGS achieve a dense, relatively thin adherent phosphate coating of relatively ?ne-sized crystals generally of a REFERENCE TO RELATED APPLICATIONS 5 size of about 5 to about 10 microns. The dry activating This application is a continuation-in-part of prior composition comprises a particulated mixture contain copending US. patent application Ser. No. 469,621 ?led ing from about 60% to about 90% by weight ofa dried Mar. 2, 1983 now abandoned. reaction product of a titanium-containing compound and sodium phosphate compound containing at least BACKGROUND OF THE INVENTION about 0.005% by weight titanium up to about 5% by A variety of compositions and processes have hereto weight titanium in combination with tetrasodium pyro fore been used or proposed for use for effecting the phosphate. The dry activating composition may option formation of an adherent, uniform phosphate coating on ally, but preferably, further contain up to about 5% by metal surfaces to enhance the adhesion of subsequently weight of monosodium phosphate based on the total applied siccative coatings and to provide for substan 5 weight of the mixture. tially improved corrosion resistance of the coated sub An aqueous bath suitable for activating metal surfaces strate. Phosphate coating processes of the various types prior to zinc phosphating is comprised by dispersing the well known and practiced in the art conventionally dry activating composition in water to provide a con comprise aqueous acidic solutions which are applied to centration of the activating composition within a range a cleaned metal surface such as by spraying, immersion, of about 0.1 up to about 10 grams (g/l) with concentra ?ooding or the like for a period of time suf?cient to tions of from about 0.75 to about 3 g/l being preferred. form a crystalline phosphate coating thereon. Numer The speci?c concentration of the activating composi ous improvements in such phosphate coating processes tion will depend to some extent on the concentration of and compositions have been made since their early titanium present in the reaction product of the activat introduction including the development of an activating 25 ing mixture and is usually controlled within the forego pretreatment to accelerate the formation of a phosphate ing ranges to provide a concentration of titanium in the coating on a metal surface and to increase the unifor activating solution within a range of about 0.001 to mity of the coating produced. One such activating treat about 0.01 g/l. ment is taught in US. Pat. No. 2,310,239 to Jernstedt in which the cleaned metal surface is ?rst contacted with In accordance with the process aspects of the present an aqueous dispersion of a dried disodium phosphate invention, a cleaned, metal substrate is contacted with titanium compound reaction product containing from the aqueous activating solution at a temperature of from about 0.005 to about 20 percent by weight titanium about 75° F. up to about 130° F. for a period of from prior to contact with the subsequent phosphating solu about 15 seconds up to about 5 minutes whereafter the tion. An improved method for producing the phos activated metal surface is contacted with a high-zinc phate-titanium reaction product is taught in US. Pat. phosphate solution of any of the types wellknown in the No. 2,874,081 to Cavanagh and Maurer the teachings of art for forming an adherent extremely ?ne crystalline which are incorporated herein by reference. size dense phosphate coating thereover. Convention The continuing demand for still further improve ally, the phosphated substrate is usually water rinsed ments in the corrosion resistance of metal substrates, followed by a sealing or post treatment rinse which may particularly ferrous-base, zinc-base and aluminum-base contain hexavalent and/or trivalent chromium ions or substrates as employed in automotive applications has may comprise a chromium-free rinse solution to en provided impetus in the development of still further hance the corrosion resistance of the phosphated sur improvements to substantially enhance corrosion pro face. The post treatment rinsed surface is usually sub tection and adherence of various siccative organic ?n 45 jected to a further water rinse and may be subjected to ishes including electrophoretic coatings applied to auto a drying step before one or a plurality of organic sicca mobile body and chassis components. The advent of tive coating are applied thereover. In those instances in more stringent corrosion test procedures adopted by which water base coatings are to be employed such as automobile manufacturers including a so-called cycle cathodically applied electrophoretic coatings, the dry test as an indication of the projected service life of a ing step can be omitted. treated automotive component has rendered many of Additional bene?ts and advantages of the present the prior art phosphating processes and compositions invention will become apparent upon a reading of the de?cient in passing such rigorous test conditions. Description of the Preferred Embodiments taken in The present invention provides for an improved acti conjunction with the speci?c examples provided. vation composition and process for activating metal 55 surfaces prior to a phosphating treatment employing DESCRIPTION OF THE PREFERRED comparatively low concentrations of the activating EMBODIMENTS constituents thereby achieving substantial economy in The dry activating composition of the present inven the treatment of metal surfaces while at the same time tion adapted for‘ dispersion in water for contacting producing comparatively thin, dense, ?ne-size crystal 60 metal surfaces to effect an activation thereof for subse line adherent phosphate coatings providing superior quent reaction with zinc phosphate coating solutions corrosion protection in comparison to prior art compo comprises a controlled mixture of a particulated dry sitions and processes heretofore known. reaction product of a titanium-containing compound and sodium phosphate compound which contains about SUMMARY OF THE INVENTION 65 0.005% up to about 5% titanium in combination with The bene?ts and advantages of the present invention particulated tetrasodium pyrophosphate. It will be un are achieved by providing a dry activating composition derstood that the term “reaction product” as herein adapted for dispersion in water in a controlled concen disclosed and as set forth in the subjoined claims encom 4,539,051 3 4 passes a reaction product produced by forming an aque stantially uniform mixture of these constituents. It is ous alkaline dispersion and/or solution of a sodium further contemplated that monosodium phosphate in a phosphate compound and a titanium compound suffi particulated form can be incorporated in the mixture in cient to provide titanium ions which are reacted for a an amount up to about 5% by weight of the total mix period of time whereafter the aqueous reaction medium ture. is evaporated to dryness and the dry reaction product is In the preparation of an aqueous solution for activat advantageously comminuted to break up any agglomer ing metal surfaces for subsequent treatment in a zinc ates formed. One method of preparing such a reaction phosphate coating process, the dried mixture is dis product is described in Us. Pat. No. 2,310,239 to Jern persed in water to produce an aqueous pretreatment stedt in which an aqueous solution containing ortho solution having a concentration of titanium ions ranging disodium phosphate is prepared to which a titanium from about 0.0002% up to about 0.05% by weight compound is added in the presence of agitation and the which generally corresponds to a concentration of the subsequent solution is evaporated to dryness at tempera dry activating mixture of from about 0.1 to about 10 g/l. tures preferably above about 60° C. According to the The pH of the pretreatment or activating solution can aforementioned patent, soluble titanium compounds are range from about 7 up to about 10 with a pH of about 8 preferably employed such as titanium tetra-chloride, to about 9.5 being preferred. The activating solution can titanium trichloride, titanium hydroxide, titanium ni be applied to the metal substrate being treated by spray, tride and titanium potassium oxalate although less solu immersion or flooding of which spray application is ble titanium compounds such as titanium carbide, tita preferred. The period of treatment during which the nium dioxide and titanium potassium ?uoride have also 20 activating solution is in contact with the metal surface produced satisfactory compounds. The reaction prod can usually range from as low as about 15 seconds up to uct upon evaporation to dryness contains from about about 5 minutes or even longer without any adverse 0.005 up to about 20% by weight of the titanium constit effects. uent. In accordance with a preferred embodiment in the A preferred method for preparing the reaction prod 25 practice of the process of the present invention, the uct is disclosed in US. Pat. No. 2,874,081 to Cavanagh dried mixture is dispersed in the form of a concentrated and Maurer the teachings of which are incorporated aqueous pretreatment solution in the presence of agita herein by reference. Briefly stated, the method dis tion and is injected under pressure in the header to closed in the last mentioned patent comprises the forma which the spray nozzles are connected for admixture tion of an aqueous solution containing a titanium com 30 with the balance of the recirculated pretreatment solu pound, preferably titanyl sulphate although other tita tion forming an activating solution containing the speci nium containing compounds which provide the tita fied concentration of activating ingredients as herein nium ion can also be satisfactorily employed, and add above set forth. In accordance with a typical commer ing to the resultant solution a phosphate compound in cial installation, the activating solution spray applied to the presence of agitation to form a slurry. The slurry is 35 the clean metal surfaces is recovered and returned to a intimately mixed for at least about 10 minutes at low storage tank from which it is again pumped under pres temperatures and the pH of the slurry is adjusted be sure to the spray header. The activating composition is tween about 5.7 and 7.8 such as by the adition ofsulfuric introduced into a smaller so-called “day tank” equipped acid or sodium hydroxide. This initial mixing or condi with agitation to provide a concentrated solution typi tioning stage is preferably conducted at a maximum 40 cally in an amount of about 10 to 15 g/l (about 1 pound temperature of about 75° F. of the dry material per 10 gallons solution) which is At the completion of the preconditioning stage which pumped and injected under pressure into the spray may range from about 10 minutes to as long as about 1 header for admixture with the recirculated activating hour, the slurry is then heated to an elevated tempera solution from the storage tank to attain a composite ture usually ranging from about 160° to about 190° F. 45 activating solution of the desired activating concentra for a further aging treatment usually for a period of tion. The use of such a concentrate for admixture and about 30 minutes or longer whereafter the slurry is dilution with the recirculated activating solution pro dried to form a powdered reaction product comprising vides for improved uniformity and better control of the the activating composition. composition of the activating solution at the point of In preparing the aqueous reaction slurry, phosphate 50 spray application to the metal surfaces. of sodium compounds can be employed including diso Following the activating treatment, the activated dium ortho-phosphate, sodium tripolyphosphate and metal substrate with or without an intervening water tetrasodium pyrophosphate as well as mixtures thereof rinse is subjected to a so-called high-zinc phosphating in which the latter two are employed in a concentration treatment employing compositions and conditions of equivalent to that produced when employing disodium 55 any of the types known in the art and particularly such phosphate to achieve the same P205 concentration. The as described in US. Pat. No. 2,835,617 to Maurer, the titanium compound and sodium phosphate compounds teachings of which are incorporated herein by refer are employed in amounts such that the dried reaction ence. For the purposes of the present invention as product contains at least about 0.005% up to about 5% herein described and as set forth in the subjoined claims, by weight titanium. 60 high-zinc phosphate solutions are intended to encom The resultant dried reaction product is preferably pass aqueous acidic solutions as described in the afore comminuted and the resultant particulated reaction mentioned patent containing about 0.5 to about 2.5 product is admixed with a particulated tetrasodium percent by weight phosphate ions, zinc ions in an pyrophosphate in an amount to provide a concentration amount sufficient to form dihydrogen phosphate ions of the reaction product of from about 60% up to about 65 and preferably less than about 0.5 percent zinc ions to 90% by weight based on the total dry mixture. This can provide a phosphate to zinc ion ratio of less than 5:1, conveniently be achieved employing a suitable blending oxidizing ions such as nitrate and/or nitrite with nitrate apparatus such as a ribbon blender for forming a sub ions being present from about 0.2 to about 1 percent, 4,539,051 5 6 preferably about 0.3 to about 0.5 percent, and nitrite porated herein by reference. The chromium-free post ions about 0.0002 to about 0.008 percent, preferably less treating composition as described in U.S. Pat. No. than about 0.005 percent; nickel ions from about 0.01 to 3,975,214 comprises a dilute aqueous solution contain; about 0.4 percent, preferably less than about 0.3 per ing about 0.1 to about 10 g/l ofa vegetable tannin which cent; optionally, copper ions from about 0.0003 to about is applied at a temperature ranging from about ambient 0.005 percent, and preferably, about 0.0003 to about up to about 200° F. at a ph less than about 6, and prefer 0.001 percent, soluble silicon such as introduced by ably from about 3 to about 6. The chromium-free post sodium silicofluoride present in an amount 0.03 percent treating composition as described in U.S. Pat. No. up to saturation and preferably from about 0.03 to about 4,039,353 comprises an aqueous solution containing a 0.1 percent, fluoride ions present in an amount suf?cient 10 melamine-formaldehyde resin preferably in further to stabilize the bath, and a total acidity as measured in combination with a vegetable tannin in which the resin accordance with the de?nition provided in the accom concentration can range as low about 0.01 g/l to con panying example of less than about 40 points. The aque centrations up to about 100 g/l. The operating post ous zinc phosphating solution is applied to the substrate treating solution is adjusted to a pH of from about 2 up at a temperature of about 130° to about 180° F., prefera 15 to about 10 and is contacted with the zinc phosphated bly from about 130° to about 160° F. surface at temperatures generally ranging from about Following the phosphating treatment, the phos ambient up to about 100° F. The chromium-free post phated substrate is usually water rinsed and is thereafter treating solution as described in U.S. Pat. No. 4,376,000 subjected to a ?nal post rinse treatment which may comprises a dilute aqueous solution containing the reac comprise solutions employing hexavalent and/or triva 20 tion product of poly-4-vinylphenol and formaldehyde lent chromium ions in an aqueous solution of a general as well as derivatives and salts thereof in which the composition such as described in U.S. Pat. Nos. concentration of the active ingredient can generally 3,222,226 and 3,279,958 the substance of which is incor range from about 0.01 percent up to about 5 percent by porated herein by reference. weight. The post-treating solution is applied at tempera Alternative satisfactory chromium-free post treating 25 tures preferably ranging from about 70° F. up to about compositions that can be employed include aqueous 160° F. and/or solvent solutions of a water soluble, or water Following the post treatment with the foregoing dispersible or water emulsi?able derivatives of polyalk chromium-free treating solutions, the phosphate treated enylphenol polymers such as isopropenylphenol, surfaces are generally preferably water rinsed prior to isobutenylphenol, dimethylvinylphenol or the like as 30 the electrophoretic coating step. more fully disclosed in pending U.S. patent application The post treatment rinsed phosphated substrate is Ser. No. 490,579, ?led May 9, 1983, entitled “Treatment usually again water rinsed, preferably employing deion of Metal With Derivative of Poly-Alkenylphenol” the ized water and is thereafter dried prior to the applica teachings of which are incorporated herein by refer tion of one or a plurality of organic siccative coatings ence. As more fully described in the aforementioned 35 thereover. In those instances in which an aqueous coat pending application, the poly-alkenylphenol derivative ing system is to be employed, a drying of the substrate compounds can range in molecular weight from the may not be required and is unnecessary in the case dimer, more usually low molecular weight oligomers of where the phosphated substrate is to be immersed in a molecular weights of about 360 to high molecular cathodic electrophoretic coating system which is now weight polymers of 30,000 or greater. The upper limit 40 extensively employed in coating automobile body and of molecular weight is functionally limited to that at chassis components to enhance corrosion resistance which the derivative remains soluble or dispersible. The thereof. compound is employed in the operating post-treatment In order to further illustrate the bene?ts and advan solution within a range of about 0.01 up to about 5 tages of the present invention, the following speci?c percent by weight with concentrations of about 0,025 to 45 examples are provided. It will be understood that the about 1 percent by weight being preferred. The solution examples are provided for illustrative purposes and are has a pH of about 0.5 to about 12, preferably about 2 to not intended to be limiting of the scope of the invention about 8 and is applied by spray, immersion, flooding or as herein disclosed and as set forth in the subjoined the like at temperatures of about 70° to about 160° F. for claims. contact times of as little as 2 to 5 seconds or even 50 longer. EXAMPLE 1 The chromium-free post treatment solution may op A series of 4 inch by 12 inch test panels comprising a tionally contain 0.001 to about 1 percent by weight of cold rolled type 1010 steel panel, a hot dip galvanized metal ions such as titanium, zirconium, hafnium and panel and an aluminum panel was subjected to a typical mixtures and salts thereof to further increase the effec 55 process for applying a phosphate coating on the sur tiveness of the post treatment. Optionally and addition faces thereof in accordance with the preferred‘ practice ally, the solution can contain organic additive agents in of the present invention whereafter the panels were combination with or in the absence of the aforemen painted and subject to a cycle test to predict the long tioned metal ions such as about 0.01 to about 4 percent term durability and corrosion resistance of the treated of thiourea, alkyl or aryl thiourea compounds, tannic 60 panels. acid, vegetable tannins or gall tannins as well as mix The phosphating process included a preliminary tures thereof. cleaning of the surfaces of the panel employing a mild In addition to the foregoing post-treating composi alkaline silicated aqueous cleaning solution at a temper tion, alternative satisfactory chromium-free post-treat ature of about 140° F. which was spray applied for a ing solutions include those as described in U.S. Pat. 65 period of 60 seconds. Following the cleaning step, the Nos. 3,975,214; 4,039,353 and 4,376,000 which through panels were contacted with a spray of an aqueous rinse mesne Assignments are assigned to the assignee of the solution containing the activating composition of the present invention and the teachings of which are incor present invention for a period of 30 seconds at room 4,539,051 7 8 temperature (75° F.) and at a pH of about 8.5. The acti panels were removed from the humidity chamber and vating solution contained 0.8 g/l of the titanium-phos immersed in a 5% sodium chloride solution at room phate reaction product and 0.2 g/l of tetrasodium pyro temperature for 15 minutes followed by a 90 minute phosphate providing a total titanium concentration of dwell period at ambient temperature and returned for about 0.008 g/l. 5 the balance of the 24 hour period in the humidity cham Following the activation rinse treatment, the panels ber at 140° F. and 85% humidity. During the sixth and were contacted with a spray applied high-zinc phos seventh days, the panels remained in the humidity phating solution for a period of 60 seconds containing chamber at 140° F. and 85% humidity. about 1.6 g/l zinc ions, about 4.6 g/l phosphate ions, At the conclusion of the 4 week cyclical test period, about 1.8 g/l nitrate ions, about 0.9 g/l fluoride ions, each of the steel, galvanized and aluminum test panels about 0.9 g/l nickel ions, about 0.04 to about 0.6 g/l were inspected and were rated with respect to the con nitrite ions and the balance water. The zinc phosphating dition of creepage of corrosion laterally from the scribe solution was applied at a temperature of about 140° F. at line. Under the rating system, a rating of 10 is excellent a total acidity of about 13 points and a free acidity of indicating no lateral creepage of corrosion whereas a about 0.8. The points of total acidity is established by 5 rating of 0 indicates complete failure. The steel and the milliliters of 0.1N sodium hydroxide solution re galvanized test panels were rated at 9-10 while the quired to neutralize a 10 milliliter sample of the solution aluminum test panels had a rating of 10. The excellent to a pH of 8.2 while the points of free acid is established cycle test performance achieved by the coated test by the number of milliliters of the same caustic solution panels treated in accordance with the activating agent required to neutralize 10 milliliters of the solution to a 20 of the present invention is believed due to the uniform pH of 3.8. dense crystalline structure of the phosphate coating The phosphated test panels are thereafter water produced and the relatively small size and uniformity of rinsed employing cold water which is spray applied for the crystalline structure thereof. a period of 30 seconds followed by a ?nal chromium Separate analyses of the phosphate coatings pro rinse sealing treatment spray applied for a period of 15 duced on the test panels prior to chromium rinsing and seconds. The chromium rinse solution is at a pH of painting revealed that the coating weight on the steel about 4.4 containing a total concentration of chromium test panels ranged from about 150 to about 200 milli ions of from about 200 to about 1,000 ppm and having a grams per square foot (mg/sq.ft.) at a crystal size of weight ratio of hexavalent chromium to trivalent chro about 5 to 10 microns. For the galvanized steel panels, mium of about 2:1. 30 the coating weight ranged from about 175 to about 250 Following the chromium rinse treatment, the test mg/sq.ft. while for the aluminum test panel the coating panels were sprayed for a period of 15 seconds with a weight ranged from about 70 to about 120 mg/sq.ft. at deionized water rinse at room temperature whereafter the same average crystal size of about 5 to about 10 the panels were immersed in an aqueous bath at a tem microns. perature of 80° F. containing a cathodic black elec While it will be apparent that the preferred embodi tropaint designated as PPG 3002 and were cathodically ments of the invention disclosed are well calculated to electri?ed to deposit a paint ?lm thickness of about 0.65 ful?ll the objects above stated, it will be appreciated to about 0.75 mils. The panels were removed and there that the invention is susceptible to modi?cation, varia after baked at about 360° F. for about 20 minutes to cure tion and change without departing from the proper the black electropaint primer. The preliminary coated 40 scope or fair meaning of the subjoined claims. panels were thereafter coated by spray application with What is claimed is: a thermosetting, high-solids solvent thinned primer 1. An improved process for phosphating metal sur sealer organic coating available under the designation faces which comprises the steps of providing an activat PPG 80-703 to provide a paint ?lm thickness of about ing composition comprising a mixture of about 60% to 0.8 to about 1.0 mils, The panels were thereafter baked 45 about 90% by weight of a particulated dried reaction for a period of 30 minutes at 350° F. to effect a curing of product of a titanium-containing compound and a so the primer-sealer coating. dium phosphate compound containing at least about Finally, an acrylic lacquer top coat designated as 0.005% by weight titanium and the balance comprising DuPont 396-Y-99612 comprising a white, 27% Lucite tetrasodium pyrophosphate, dispersing said activating dispersion lacquer was spray applied to a ?lm thickness composition in water at a concentration of about 0.1 to of about 2 to about 2.5 mils whereafter the panels were about 10 g/l to provide an activating solution, contact subjected to a ?nal bake at 325° F. for 30 minutes. The ing a clean metal surface with said activating solution at painted test panels were thereafter aged for a period of a pH of about 7 to about 10 for a period of time of at 3 days and were thereafter scribed on one face thereof least about 15 seconds to provide an activated metal with a vertical scribe line passing through the organic surface, contacting the activated metal surface with an coatings and phosphate coatings to the base metal. aqueous high-zinc phosphating solution for a period of The scribed panels were thereafter subjected to a time to produce a desired thickness of a zinc phosphate cyclical corrosion test for a period of 4 weeks employ coating thereon, rinsing the zinc phosphate coating ing a weekly cycle as follows: On the ?rst day, the with a dilute aqueous solution containing chromium panels were heated in dry heat to a temperature of about 60 ions, and thereafter applying an electrophoretic organic 140° F. for a period of 1 hour and thereafter chilled to coating to the rinsed zinc phosphate coating. a temperature of —10° F. for a period of 30 minutes 2. The process as de?ned in claim 1 in which the step followed by a 15 minute immersion in a 5% solution of of dispersing said activating composition is performed sodium chloride at room temperature. The panels were to provide a concentration of about 0.75 to about 3 g/l then retained for a period of 90 minutes at ambient 65 of said activating composition in said activating solu temperature and thereafter replaced in a humidity tion. chamber at 140° F. at 85% humidity for the balance of 3. The process as de?ned in claim 1 in which the step the 24 hour period. During each of the next 4 days, the of dispersing said activating composition is performed 4,539,051 9 10 to provide a concentration of titanium in said activating dium phosphate compound containing at least about solution of about 0.00l to about 0.01 g/l. 0.005% by weight titanium and the balance comprising 4. The process as de?ned in claim 1 in which the step tetrasodium pyrophosphate, dispersing said activating. of dispersing said activating composition is performed composition in water at a concentration of about 0.1 to to provide a concentration of titanium in said activating about 10 g/l to provide an activating solution, contact solution of about 0.0002 to about 0.05% by weight. ing a clean metal surface with said activating solution at 5. The process as de?ned in claim 1 including the a pH of about 7 to about 10 for a period of time of at further step of controlling the temperature of said acti least about 15 seconds to provide an activated metal vating solution within a range of about 75° to about 130° surface, contacting the activated metal surface with an F. during the step of spray applying said activating aqueous high-zinc phosphating solution for a period of solution to a metal surface time to produce a desired thickness of a zinc phosphate 6. The process as de?ned in claim 1 in which the pH coating thereon, post-treatment rinsing the zinc phos of said activating solution is controlled within a range of phate coating with a dilute substantially chromium-free about 8 to about 9.5. post-treating solution to enhance the corrosion resis 7. The process as de?ned in claim 1 in which the step tance of the zinc-phosphated surface, and thereafter of spray applying said activating solution is performed applying an electrophoretic organic coating to the for a period of time up to about 5 minutes. rinsed zinc phosphate coating. 8. The process as de?ned in claim 1 including the 16. The process as de?ned in claim 15 in which the further step of water rinsing the activated metal surface step of dispersing said activating composition is per prior to the step’of contacting the activated metal sur formed to provide a concentration of about 0.75 to face with the aqueous high-zinc phosphating solution. 20 about 3 g/l of said activating composition in said acti 9. The process as de?ned in claim 1 including the vating solution. further step of water rinsing the zinc phosphate coating 17. The process as de?ned in claim 15 in which the prior to the step of rinsing the zinc phosphate coating step of dispersing said activating composition is per with the dilute aqueous solution containing chromium formed to provide a concentration of titanium in said ions. 25 activating solution of about 0.001 to about 0.01 g/l. 10. The process as defined in claim 1 including the 18. The process as de?ned in claim 15 in which the further step of water rinsing the zinc phosphate coating step of dispersing said activating composition is per following the step of rinsing the zinc phosphate coating formed to provide a concentration of titanium in said with a dilute aqueous solution containing chromium activating solution of about 0.0002 to about 0.05% by ions. 30 weight. 11. The process as de?ned in claim 1 including the 19. The process as de?ned in claim 15 including the ' further step of drying the zinc phosphate coating prior further step of controlling the temperature of said acti to the step of applying the organic coating. vating solution within a range of about 75° to about 130° 12. The process as de?ned in claim 1 in which the step F. during the step of spray applying said activating of applying the organic coating includes immersing the 35 solution to a metal surface. zinc phosphate coated metal surface in an aqueous bath 20. The process as de?ned in claim 15 in which the containing an electropaint therein and cathodically pH of said activating solution is controlled within a electrifying the metal surface to deposit a desired thick range of about 8 to about 9.5. ness of electropaint coating thereon. 21. The process as de?ned in claim 15 in which the 13. The process as de?ned in claim 12 including the 40 step of spray applying said activating solution is per further steps of drying and curing the electropaint coat formed for a period of time up to about 5 minutes. ing and thereafter applying at least one additional or 22. The process as de?ned in claim 15 including the ganic coating on the electropaint coating. further step of water rinsing the activated metal surface 14. An improved process for phosphating metal sur prior to the step of contacting the activated metal sur faces which comprises the steps of providing an activat 45 face with the aqueous high-zinc phosphating solution. ing composition comprising a mixture of about 60% to 23. The process as de?ned in claim 15 including the about 90% by weight of a particulated dried reaction further step of water rinsing the zinc phosphate coating product of a titanium-containing compound and a so prior to the step of rinsing the zinc phosphate coating dium phosphate compound containing at least about with the dilute substantially chromium-free post-treat 0.005% by weight titanium and the balance comprising ing solution. tetrasodium pyrophosphate, dispersing said activating 24. The process as de?ned in claim 15 including the composition in water at a concentration of about 0.l to further step of water rinsing the zinc phosphate coating about l0 g/l to provide an activating solution, contact following the step of rinsing the zinc phosphate coating ing a clean metal surface with said activating solution at with the dilute substantially chromium-free post-treat a pH of about 7 to about l0 for a period of time of at ing solution. least about 15 seconds to provide an activated metal 25. The process as de?ned in claim 15 including the surface, contacting the activated metal surface with an further step of drying the zinc phosphate coating prior aqueous high-zinc phosphating solution for a period of to the step of applying the organic coating. time to produce a desired thickness of a zinc phosphate 26. The process as de?ned in claim 15 in which the coating thereon, post-treatment rinsing the zinc phos step of applying the organic coating includes immersing phate coating with a dilute post-treating solution to the zinc phosphate coated metal surface in an aqueous enhance the corrosion resistance of the zinc-phosphated bath containing an electropaint therein and cathodically surface, and thereafter applying an electrophoretic or electrifying the metal surface to deposit a desired thick ganic coating to the rinsed zinc phosphate coating. ness of electropaint coating thereon. 15. An improved process for phosphating metal sur 27. The process as de?ned in claim 26 including the faces which comprises the steps of providing an activat 65 further steps of drying and curing the electropaint coat ing composition comprising a mixture of about 60% to ing and thereafter applying at least one additional or about 90% by weight of a particulated dried reaction ganic coating on the electropaint coating. product of a titanium-containing compound and a so * * 1F * *