Multilayered coating for downhole tools with enhanced wear resistance and acidic corrosion resistance
AssigneeNational Oilwell DHT, L.P.
InventorsJiinjen Albert Sue, Unnikrishnan C. Vasudevan, Rajagopala N. Pillai
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Abstract
A coating for protecting a base material from wear and corrosion includes a first layer deposited directly onto an outer surface of the base material. In addition, the coating includes a second layer deposited directly onto the first layer. The first layer is positioned between the base material and the second layer. The first layer includes chromium having a first micro-crack density and the second layer comprises chromium having a second micro-crack density that is less than the first micro-crack density.
Claims21
A coating for protecting a base material from wear and corrosion, the coating comprising:
- a first layer deposited directly onto an outer surface of the base material;
- and
- a second layer deposited directly onto the first layer, wherein the first layer is positioned between the base material and the second layer;
- wherein the first layer a comprises a first micro-crack density and the second layer comprises a second micro-crack density, wherein the first micro-crack density is greater than 1000 micro-cracks per inch, and the second micro-crack density is between 400 and 650 micro-cracks per inch;
- wherein the first layer or the second layer comprises chromium.
A down-hole tool comprising:
- a body made of a base material;
- a protective coating mounted to an outer surface of the base material, wherein the protective coating comprises:
- a first layer deposited directly onto an outer surface of the base material;
- and
- a second layer deposited directly onto the first layer, wherein the first layer is positioned between the base material and the second layer;
- wherein the first layer a comprises a first micro-crack density and the second layer comprises a second micro-crack density, wherein the first micro-crack density is greater than 1000 micro-cracks per inch and the second micro-crack density is between 400 and 650 micro-cracks per inch;
- wherein the first layer or the second layer comprises chromium.
A method for forming a wear and corrosion resistant coating on a surface of a base material, the method comprising:
- (a) depositing a first layer comprising a first material onto the surface of the base material at a first current density, wherein the first layer has a first micro-crack density greater than 1000 micro-cracks per inch;
- and
- (b) depositing a second layer of a second material onto the first layer after (a) at a second current density, wherein the second current density is different than the first current density, and wherein the second layer has a second micro-crack density between 400 and 650 micro-cracks per inch;
- wherein the first material or the second material comprises chromium deposited at the first current density or the second current density, respectively, of about 3.5 A/in2.
Dependencies are inferred from the claim text.