Search

EP-4735665-A1 - COMPOSITIONS AND METHODS FOR TREATING A SUBSTRATE AND TREATED SUBSTRATES

EP4735665A1EP 4735665 A1EP4735665 A1EP 4735665A1EP-4735665-A1

Abstract

Disclosed herein is an aqueous treatment composition comprising an acid, such as a fluorometallic acid, and a fluoride salt. Further disclosed in a pretreatment composition comprising an acid, a source of a metal, a source of free fluoride, and an aqueous medium. Also disclosed are methods of treating metal substrates, treated metal substrates, and kits.

Inventors

  • DIMEGLIO, John Leonard
  • MCMILLEN, MARK WILLIAM
  • ESAREY, Samuel Logan
  • RAKIEWICZ, EDWARD F.
  • HAN, Aijie
  • DE LA GARZA, Gloria Ovaert
  • MAZZOCCO, JR., Richard Robert

Assignees

  • PPG Industries Ohio Inc.

Dates

Publication Date
20260506
Application Date
20240627

Claims (20)

  1. What is claimed is: 1. An aqueous treatment composition comprising: more than 0.0% by weight and up to 28% by weight of a fluorometallic acid, based on the total weight of the composition; and a fluoride salt, wherein the fluoride salt is a different component than the fluorometallic acid; wherein the aqueous treatment composition comprises less than 30% by weight nitric acid, based on the total weight of the composition.
  2. 2. The aqueous treatment composition of claim 1, wherein the fluorometallic acid is present in an amount up to 5% by weight, based on the total weight of the composition.
  3. 3. The aqueous treatment composition of any of the preceding claims, wherein the metal in the fluorometallic acid comprises a Group IIIA metal, a Group IVA metal, a Group IVB metal, and/or a Group VIII metal, and the fluoride in the fluorometallic acid has a mole ratio to the Group IIIA metal, Group IVA metal, Group IVB metal, Group VI metal, and/or Group VIII metal of more than 4.
  4. 4. The aqueous treatment composition of any of the preceding claims, wherein the fluorometallic acid comprises hexafluorosilicic acid.
  5. 5. The aqueous treatment composition of any of the preceding claims, wherein the fluoride salt comprises ammonium bifluoride.
  6. 6. The aqueous treatment composition of any of the preceding claims, wherein the aqueous treatment composition comprises free fluoride in an amount of at least 2 ppm, based on total weight of the pretreatment composition; and total fluoride in an amount of at least 50 ppm, based on total weight of the pretreatment composition.
  7. 7. A method of treating a metal substrate comprising contacting at least a portion of the metal substrate with the aqueous treatment composition of any of the preceding claims.
  8. 8. The method of claim 7, wherein the metal substrate comprises titanium and/or a titanium alloy.
  9. 9. A metal substrate treated according to the method of claim 8.
  10. 10. The metal substrate of claim 9, wherein a ratio of the percentage of Ti 3+ to the percentage of Ti 2+ of the metal substrate as measured using high resolution X-ray photoelectron spectroscopy is at least 0.7.
  11. 11. The metal substrate of any of claims 9 or 10, wherein the metal substrate has an interfacial contact resistivity of less than 5 mΩ cm 2 , as measured according to the ICR TEST METHOD
  12. 12. The metal substrate of any of claims 9-11, wherein the metal substrate treated with the aqueous treatment composition has a TOF-SIMs depth profile for H+/Ti+ relative ion intensity inverse peak within 0-5 nm depth of at least 0.002, and/or the metal substrate treated with the aqueous treatment composition has a TOF-SIMs depth profile for Na + /Ti + relative ion intensity inverse peak within 0.5 nm depth of no more than 3.2.
  13. 13. A pretreatment composition comprising: an acid; a source of a metal comprising vanadium, manganese, nickel, silicon, ruthenium, rhodium, palladium, gold, tin, tantalum, tungsten, iridium, silver, mercury, thallium, lead, bismuth, polonium, platinum, niobium, titanium, cerium, or a combination thereof; a source of free fluoride; and an aqueous medium, wherein the acid, the source of a metal, and the source of free fluoride are each different components.
  14. 14. The pretreatment composition of claim 13, wherein the metal comprises niobium, platinum, or gold.
  15. 15. The method of any of claims 7-8, wherein the method further comprises contacting at least a portion of the metal substrate with the pretreatment composition of any of the preceding claims 13-14.
  16. 16. The method of claim 15, wherein the method further comprises (1) heating the pretreatment composition to a temperature of 30°C to 60°C, and/or (2) stirring the pretreatment composition during contacting the metal substrate with the pretreatment composition.
  17. 17. A metal substrate treated according to the method of claim 16.
  18. 18. The metal substrate of any of the preceding claims 9-12 or 16, wherein the metal substrate comprises a part of a proton exchange membrane electrolyzer.
  19. 19. The metal substrate of any of the preceding claims 9-12 or 16, wherein the metal substrate comprises a part of a composite structure.
  20. 20. A kit comprising: the aqueous treatment composition of any of claims 1-6, and/or the pretreatment composition of any of claims 13-14, and optionally instructions for treating a substrate with the aqueous treatment composition, the pretreatment composition, or both the aqueous treatment composition and the pretreatment composition.

Description

COMPOSITIONS AND METHODS FOR TREATING A SUBSTRATE AND TREATED SUBSTRATES FIELD [0001] The present disclosure relates to compositions and methods for treating a substrate as well as treated substrates. BACKGROUND [0002] The use of protective coatings on metal substrates for improved corrosion resistance. In addition to disrupting the integrity of the metal substrate, corrosion also poses problems for metal substrates used in electrical current transmission because corrosion products increase the resistance of the metal substrate at the substrate surface. For example, porous titanium metal is commonly used as a current collector in proton exchange membrane (PEM) electrolyzers and is coated with precious metals (such as platinum, iridium, or gold) by physical vapor deposition or electroplating to prevent growth of an insulating TiO2 layer that increases internal device resistance and limits hydrogen production capabilities. However, precious metals are expensive and physical vapor deposition requires use of a high-vacuum environment. SUMMARY [0003] Disclosed herein is an aqueous treatment composition comprising more than 0.0% by weight and up to 28% by weight of a fluorometallic acid, based on the total weight of the composition; and a fluoride salt, wherein the fluoride salt is a different component than the fluorometallic acid; wherein the aqueous treatment composition comprises less than 30% by weight nitric acid, based on the total weight of the composition. [0004] Further disclosed herein is a method of treating a metal substrate comprising contacting at least a portion of the metal substrate with the aqueous treatment composition disclosed herein. [0005] Further disclosed herein is a metal substrate treated according to the method of treating a metal substrate disclosed herein. [0006] Further disclosed herein is a pretreatment composition comprising: an acid; a source of a metal comprising vanadium, manganese, nickel, silicon, ruthenium, rhodium, palladium, gold, tin, tantalum, tungsten, iridium, silver, mercury, thallium, lead, bismuth, polonium, platinum, niobium, titanium, cerium, or a combination thereof; a source of free fluoride; and an aqueous medium, wherein the acid, the source of a metal, and the source of free fluoride are each different components. [0007] Further disclosed herein is a metal substrate treated by a method comprising contacting at least a portion of the metal substrate with the aqueous treatment composition disclosed herein and contacting at least a portion of the metal substrate with the pretreatment composition disclosed herein. [0008] Further disclosed is a kit comprising: the aqueous treatment composition disclosed herein and/or the pretreatment composition disclosed herein, and optionally instructions for treating a substrate with the aqueous treatment composition, the pretreatment composition, or both the aqueous treatment composition and the pretreatment composition. BRIEF DESCRIPTION OF THE FIGURES [0009] Figure 1 shows an isometric view of an aperture of a portion of an expanded metal mesh porous metal substrate. [0010] Figure 2 is SEM images of chemically pure grade-1 titanium foil: A) before, and B) after treatment. [0011] Figure 3 is a bar graph showing contact angle of water and diiodomethane of the titanium surface before and after exposure to the treatment solution. [0012] Figure 4 is a graph showing grazing incidence X-ray diffraction pattern of untreated and treated titanium foil, highlighting the change in relative (002) and (101) reflection intensity. [0013] Figure 5 is a bar graph showing interfacial contact resistivity (ICR) data of untreated and treated titanium foils after the listed exposure time to 2.4 V vs. NHE in pH 3 sulfuric acid. [0014] Figure 6 is SEM images of chemically pure grade-1 titanium foil exposed to 2.4 V vs. NHE in pH 3 sulfuric acid for 250 h: A) without and B) with treatment. [0015] Figure 7 is a bar graph showing interfacial contact resistivity (ICR) data of untreated and treated titanium foils after 1 hour exposure to 400°C. [0016] Figure 8 is a graph showing TOF-SIMs depth profile for H+/Ti+ relative ion intensity of titanium foil and two treated titanium samples. [0017] Figure 9 is a graph showing TOF-SIMs depth profile for Na+/Ti+ relative ion intensity of titanium foil and two treated titanium samples. [0018] Figure 10 is a bar graph showing interfacial contact resistivity (ICR) growth rate over 50 hours of electrolysis at 2.4 V vs. NHE in pH 3 sulfuric acid of various titanium foils exposed to 3.4 wt.% ammonium bifluoride with the listed co-acids. [0019] Figure 11 shows XRF spectra of the titanium substrate treated with only the first treatment solution (dotted) compared to the substrate further treated with the niobium-containing pretreatment composition (solid). The two vertical lines indicate the Kα1 and Kα2 of Nb signal. [0020] Figure 12 shows XRF spectra of Pt coated Ti foil compared with bare Ti foil without coating (