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
  • C23C22/60—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 alkaline aqueous solutions with pH greater than 8
  • C23C22/66—Treatment of aluminium or alloys based thereon
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K5/00—Heat-transfer, heat-exchange or heat-storage materials, e.g. refrigerants; Materials for the production of heat or cold by chemical reactions other than by combustion
  • C09K5/20—Antifreeze additives therefor, e.g. for radiator liquids
• • 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
  • C23C22/68—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 solutions with pH between 6 and 8
• • 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
  • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
  • C23F11/00—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent
  • C23F11/08—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids
  • C23F11/18—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids using inorganic inhibitors
  • C23F11/184—Phosphorous, arsenic, antimony or bismuth containing compounds
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
  • F28F19/00—Preventing the formation of deposits or corrosion, e.g. by using filters or scrapers
  • F28F19/02—Preventing the formation of deposits or corrosion, e.g. by using filters or scrapers by using coatings, e.g. vitreous or enamel coatings

Definitions

• the invention relates generally to compositions and methods for passivating surfaces of components and parts in heat exchanger systems that employ coolants for heat transfer.
• US Patent No 4,587,028 discloses non-silicate antifreeze formulations containing alkali metal salts of benzoic acid, dicarboxylic acids and nitrate.
• US patent No 4,647,392 discloses a corrosion inhibitor comprising the combination of an aliphatic monoacid or salt, a hydrocarbyl dibasic acid or salt and a hydrocarbonyl triazole.
• the invention relates to a novel method to extend the life of coolant fluids in heat exchanger systems, utilizing a solution containing phosphate ions to wash / passivate the aluminium parts and components of the heat exchanger systems prior to contact with the coolant fluids.
• a method for treating parts in a heat exchanger system which parts have metal surfaces which chemically and detrimentally interact with additives in coolant fluids in the heat exchanger system, by contacting the metal surfaces with a phosphate-containing solution for the phosphate-containing solution to passivate the metal surface for subsequent contact with the coolant fluids.
• the invention relates to the use of a phosphate-containing solution having a pH of 4.0 - 12.0 and containing 0.005 to 30 g/1 of phosphate ions to treat parts in a heat exchanger system, which parts have metal surface that chemically and detrimentally interact with additives in coolant fluids in the heat exchanger system.
• the phosphate ions in the phosphate-containing solution reduce the chemical activity of the metal surface for subsequent contact with the coolant fluid.
• heat exchange system refers to applications wherein cooling systems are used, including but not limited to fuel cell assemblies, appliances and engine applications.
• Non-limiting examples include heater cores and radiators for engines as commonly used in automobiles, trucks, motorcycles, aircrafts, trains, tractors, generators, compressors, for various stationary engine and equipment applications, marine engine applications and the like.
• heat exchange component refers to parts, bodies, or components of heat exchange systems, including but not limited to radiators, water pump, thermostats, engine head, cylinder liners, separator plates in fuel cells, heater cores, and the like.
• the term “treat,” “treating” or “treated” may be used interchangeably with “passivate,” “passivating,” or “passivated,” referring to one embodiment of the invention, wherein the heat exchanger part is washed (brought into contact) with the phosphate-containing solution to reduce the chemical reactivity of the washed surface, which is to be subsequently in contact with coolant fluids in the heat exchanger system.
• heat transfer fluid refers to a fluid which flows through a heat exchange system in order to prevent its overheating, transferring the heat produced within the system to other systems or devices that can utilize or dissipate the heat.
• glycol-based includes glycols, glycerins, as well as glycol ethers.
• a method to treat heat exchanger parts e.g., surfaces such as heater cores, radiators and brazed parts, etc.
• the parts are treated with a passivating solution to reduce the chemical reactivity of their surfaces.
• Passivating Solution The composition for passivating surfaces in heat exchange systems contains as its essential ingredient phosphate ions, in a pH range of 4.0 - 12.0. In a second embodiment, the composition is a neutral to slight alkaline solution containing phosphate ions having a pH of 6.5 - 11.
• the phosphate ions are present in the solution in a sufficient amount to reduce the chemical activity of the surfaces in contact with the coolant fluid.
• the sufficient amount of phosphate ions is from 0.005 to 30 g/1 of solution.
• the phosphate ions are present in an amount from 0.01 to 25 g/1 of solution.
• the phosphate ions can be introduced to the solution in the form of any soluble phosphate compound including alkali metal phosphates, ammonium phosphates, polyphosphates, pyrophosphates, phosphoric acid, and the like.
• the passivating solution comprises di potassium hydrogen phosphate (K 2 HPO 4 ) in solution.
• the solution comprises mono potassium phosphate (KH 2 PO 4 ) in aqueous solution.
• the passivating solution is a solution of diammonium phosphate.
• the passivating solution is aqueous based, with the aqueous medium being selected from the group consisting of water, neutral aqueous solutions, acidic aqueous solutions and basic aqueous solutions.
• the passivating solution comprises di potassium hydrogen phosphate in a water base with a sufficient amount of at least an alkali metal hydroxide, e.g., NaOH or KOH, added for its pH to be between 7 and 10.
• the passivating solution has as its base a glycol based or non-glycol based coolant, as the heat transfer fluid to be used in the system is subsequently a glycol or non-glycol based antifreeze.
• the phosphate-containing passivating solution has as its base a glycol-based solution containing glycol or glycol ether in an amount of 2 to 97 wt. % of total weight of a final passivating solution.
• the amount of glycol or glycol ether ranges from 2 to 50 wt. %.
• Non-limiting examples include alkylene glycols, such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol; Methylene glycol, tetraethylene glycol, pentaethylene glycol, hexaethylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, pentapropylene glycol, hexapropylene glycol and mixtures thereof and glycol monoethers such as the methyl, ethyl, propyl, and butyl ethers of ethylene glycol, and mixtures thereof.
• alkylene glycols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol
• the phosphate-containing passivating solution has as its base a non-glycol aqueous medium containing at least an alkali metal salt of anions selected from acetates, formates, proprionates, adipiates, and succinates, in an amount of 2 to 97 wt. % of total weight of a final passivating solution.
• non-glycol based aqueous medium include but are not limited to glycerine, ethanol, potassium formate, potassium propionate, potassium acetate, dipotassium adipinate, and mixtures thereof.
• one or more components known in the art as "phosphating accelerators” can be optionally added to the passivating solution, allowing the surfaces to be treated more uniformly with the phosphate ions.
• phosphating accelerators include m- nitrobenzene sulfonate ions at 0.05 to 2 g/L, hydroxylamine in free or bound form at 0.1 to 10 g/1, m-nitrobenzoate ions at 0.05 to 2 g/1, p-nitrophenol at 0.05 to 2 g/1, hydrogen peroxide in free or bound form at 1 to 70 mg/1, organic N-oxides at 0.05 to 10 g/1, nitroguanidine atO.l to 3 g/1.
• nitrite ions at 1 to 500 mg/1 and chlorate ions 0.5 to 5 g/1.
• traditional corrosion inhibitors known in the art can be optionally added to the phosphate containing solution in an amount ranging from 0.005 to 10 wt. %.
• Non-limiting examples include triazoles, nitrates, nitrites, silicates, borates, molybdates, organic aromatic and aliphatic acid salts and mixtures thereof, hi one embodiment, the phosphate containing passivating solution further comprises at least a corrosion inhibitor selected from the group of alkali metal borates, alkali metal silicates, alkali metal benzoates, alkali metal nitrates, alkali metal nitrites, alkali metal molybdates, hydrocarbyl thiazoles, and mixtures thereof.
• the combination of soluble phosphate compounds and optional additives can be blended into the aqueous medium matrix individually or in various sub- combinations to formulate the passivating solution.
• the passivating solution may be in the form of a single package or in the form of two packages, with one containing the passivating solution (with the phosphate ions), and one containing a coolant which can be a diluted form of the coolant fluid to be subsequently used in the heat exchanger system.
• the treatment / passivating process is carried out at a temperature ranging from 10 to 14O 0 C, with the passivating solution maintained at a temperature ranging from 20 to 9O 0 C. In one embodiment, the treating process is carried out at room temperature.
• the passivating solution can be applied to the surface to be treated using methods known in the art, including spraying, immersions, circulation of fluid in cooling system or by a no-rinse method such as using rollers. Whether the passivating solution is applied by spray, no-rinse method, or immersion, in one embodiment, the treating time is between 5 seconds and 12 hours. In a second embodiment, the time is from 30 seconds and 6 hours. In a third embodiment, the treatment time is between 5 minutes and 2 hours. In a fourth embodiment, the treatment time ranges from 15 - 60 minutes.
• the heat exchanger system may be drained and the treated parts are optionally rinsed with a rinse solvent, e.g. deionized water.
• a rinse solvent e.g. deionized water.
• the system may be rinsed with a diluted concentration of the coolant fluid to be added to the heat exchanger system, thus minimizing the amount of and / or any residual effect of any passivating solution that may be retained in the system.
• coolant fluids for the normal operation of the heat exchanger system can be finally added to the system.
• the treatment with the passivating solution may clean the surfaces of the parts / components in the heat exchange systems.
• the solution may also remove oil, sludge, corrosion products and other undesirable contaminants and / or deposits on the surface of the parts.
• the composition may disperse and / or dissolve these species into the solution, which solution is subsequently removed / drained away along with the undesirable species in the optional rinsing step.
• the passivating solution is useful for treating heat exchanger systems having metal parts comprising components that chemically and detrimentally interact with additives in coolant fluids.
• additives means that at least an additive in the coolant fluid is reduced in efficacy and / or useable lifetime, as measured by the amount of active ingredients in the additive, with a reduction of at least 25% reduction in at least an additive such as a corrosion inhibitor after 2 weeks in use.
• the detrimental chemical interaction can also be shown in a change in the pH of the coolant over time, e.g., a change in the pH of at least + 1 after 2 wks.
• the method is for treating heat exchanger parts formed by processes including casting, rolling, forming, brazing, and combinations of the above.
• the method is for treating heat exchanger parts comprising zinc, magnesium, aluminium, alloys of these materials.
• the method is for treating heat exchanger parts comprising aluminium and / or alloys thereof.
• the method is for treating heat exchanger parts brazed with flux materials that chemically and detrimentally interact with additives in coolant fluids.
• the method is for treating parts brazed with a fluorine- containing flux.
• fluorine-containing fluxing material include potassium fluoroborate, potassium fluoroaluminate, cesium fluoroaluminate, potassium fluorozudie, cesium fluorozudie, and mixtures thereof.
• the treatment using the passivating solution substantially inactivates the chemical reactivity of the metal surfaces in heat exchanger systems towards coolant fluids.
• an Organic Acid Technology (OAT) coolant employing a traditional inhibitor such as nitrite
• the treatment stabilizes the nitrite depletion when the coolant fluid is added to a heat exchanger system employing treated part, with a reduction in the nitrite level of less than 25% after 2 weeks in use.
• the nitrite reduction level is less than 10%.
• the stability effect of the passivating treatment is shown in the pH level of the coolant, with the coolant pH remains essentially stable, i.e., showing a variation of less than 10% after 2 wks. in use.
• coupons (cubes) of 1 A" to 1" in size of brazed aluminium radiator parts were treated by immersion in washing fluids from 15 minutes to overnight (10 hrs.)- The parts were brazed with potassium fluoro aluminates as flux materials - which were previously considered an inert material under normal conditions. After washing, the coupons were immersed in the OAT coolant for a period of 2 weeks, with the coolant bath temperature being maintained at about 195 0 F.
• the OAT coolant has a starting pH of 8.5 and a nitrite level of 580 ppm. pH level, nitrite and fluoride contents in the OAT coolant are measured after the 2 wk. test.
• Washing fluid formula E is an aqueous solution employing 1 - 2 wt. % di potassium hydrogen phosphate (K 2 HPO 4 ).
• the corrosion inhibitor components making up the washing fluid formulae C - G are shown in Table 2 below, with the phosphate ions in washing fluid formulae E-G provided by di potassium hydrogen phosphate (K 2 HPO 4 ) in the aqueous washing solutions:
• Example 1 the coupon was not treated / washed at all.
• Example 2 the coupon was washed with water.
• the coupons were treated with the washing fluids having compositions shown in Table 2, with the washing fluid compositions E - G having 0.4-2 wt. % Of K 2 HPO 4 in water, the OAT coolant, or a traditional mineral coolant.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Organic Chemistry (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Inorganic Chemistry (AREA)
• Combustion & Propulsion (AREA)
• General Engineering & Computer Science (AREA)
• Preventing Corrosion Or Incrustation Of Metals (AREA)
• Chemical Treatment Of Metals (AREA)

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• 2008
  • 2008-07-25 WO PCT/US2008/071123 patent/WO2009018123A1/en not_active Ceased
  • 2008-07-25 CA CA2695183A patent/CA2695183A1/en not_active Abandoned
  • 2008-07-25 BR BRPI0814734A patent/BRPI0814734A2/pt not_active IP Right Cessation
  • 2008-07-25 JP JP2010520091A patent/JP2010535324A/ja active Pending
  • 2008-07-25 MX MX2010001299A patent/MX2010001299A/es unknown
  • 2008-07-25 AU AU2008282497A patent/AU2008282497A1/en not_active Abandoned
  • 2008-07-25 EP EP08796596A patent/EP2176446A1/en not_active Withdrawn
  • 2008-07-25 EA EA201070223A patent/EA201070223A1/ru unknown
  • 2008-07-25 CN CN200880106015A patent/CN101809201A/zh active Pending
  • 2008-08-04 US US12/185,662 patent/US20090045379A1/en not_active Abandoned
• 2010
  • 2010-02-11 ZA ZA2010/01019A patent/ZA201001019B/en unknown

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