Sealed HVOF carbide coating
Sealing a thermal spray coating with an extensively diluted sealant, such as a thermosetting epoxy resin, allows the sealant to more effectively protect the coating against leakage, wear and corrosion. The dilution of the sealant is believed to enhance penetration of the sealant into the coating. Such sealed coatings are useful in oilfield applications.
1 . A composition comprising a thermal spray coating and a thermally-cured sealant, wherein the sealant penetrates the coating sufficiently to be resistant to one or more of high pressure fluids, corrosive fluids, wear and erosion.
2 . The composition of claim 1 , wherein the sealant penetrates the coating to a depth of at least 0.05 mm.
3 . The composition of claim 1 , wherein the sealant is applied to the coating by diluting the sealant with at least 30% by weight of a suitable solvent.
4 . The composition of claim 3 , wherein the sealant is applied to the coating by diluting the sealant with at least 40% by weight of a suitable solvent.
5 . The composition of claim 4 , wherein the sealant is applied to the coating by diluting the sealant with at least 50% by weight of a suitable solvent.
6 . The composition of claims 1 , wherein the coating is a high velocity oxygen-fuel deposition (HVOF) coating.
7 . The composition of claim 6 , wherein the coating is a tungsten carbide-cobalt-chromium coating.
8 . The composition of claim 7 , wherein the coating is a WC-10Co-4Cr coating and contains no more than one percent by weight of iron.
9 . The composition of claim 6 , wherein the coating is a tungsten carbide-cobalt coating, a titantium carbide-iron coating, a titantium carbide-cobalt-chrome coating or a chrome carbide-nickel chrome coating.
10 . The composition of claims 1 , wherein the sealant is a thermosetting epoxy resin.
11 . The composition of claim 1 , wherein the composition is suitable for oilfield service.
12 . The composition of claim 1 , wherein the coating and sealant are applied to a substantially planar surface.
13 . A gate valve comprising the composition of claims 1 .
14 . A method for protecting thermal spray coatings, comprising extensively diluting a thermosetting sealant and applying the sealant to the coating, thereby protecting the coating.
15 . The method of claim 14 , wherein the sealant is applied to the coating by diluting the sealant with at least 30% by weight of a suitable solvent.
16 . The method of claim 15 , wherein the sealant is applied to the coating by diluting the sealant with at least 40% by weight of a suitable solvent.
17 . The method of claim 16 , wherein the sealant is applied to the coating by diluting the sealant with at least 50% by weight of a suitable solvent.
18 . The method of claims 14 , wherein the coating is a high velocity oxygen-fuel deposition (HVOF) coating.
19 . The method of claim 18 , wherein the coating is a tungsten carbide-cobalt-chromium coating.
20 . The method of claim 19 , wherein the coating is a WC-10Co-4Cr coating and contains no more than one percent by weight of iron.
21 . The method of claim 18 , wherein the coating is a tungsten carbide-cobalt coating, a titantium carbide-iron coating, a titantium carbide-cobalt-chrome coating or a chrome carbide-nickel chrome coating.
22 . The method of claims 14 , wherein the sealant is a thermosetting epoxy resin.
23 . The method of claim 14 , wherein the protected thermal spray coating is suitable for oilfield service.
24 . The method of claim 14 , further comprising curing the sealant after it is applied.
25 . The method of claim 14 , further comprising grinding the coating after the sealant is applied.
26 . A method of preparing a sealed thermal spray coating, comprising extensively diluting a thermosetting sealant and applying the sealant to the coating, thereby protecting the coating.
27 . The method of claim 26 , wherein the sealant is applied to the coating by diluting the sealant with at least 30% by weight of a suitable solvent.
28 . The method of claim 27 , wherein the sealant is applied to the coating by diluting the sealant with at least 40% by weight of a suitable solvent.
29 . The method of claim 28 , wherein the sealant is applied to the coating by diluting the sealant with at least 50% by weight of a suitable solvent.
30 . The method of claim 26 , wherein the coating is a high velocity oxygen-fuel deposition (HVOF) coating.
31 . The method of claims 26 , wherein the sealant is a thermosetting epoxy resin.