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US 9,758,891 B2Granted
Low stress property modulated materials and methods of their preparation
AssigneeModumetal, Inc.
InventorZhi Liang Bao
Life of this patent
Estimating the term…
Abstract
The technology described herein sets forth methods of making low stress or stress free coatings and articles using electrodeposition without the use of stress reducing agents in the deposition process. The articles and coatings can be layered or nanolayered wherein in the microstructure/nanostructure and composition of individual layers can be independently modulated.
Claims43
A method of applying a low stress coating to a substrate, or of electroforming a low stress article, using electrodeposition comprising:
- forming a low stress coating or low stress electroformed article having a stress less than 400 MPa by applying an electrical current to said substrate, said current having a time varying current density
- wherein the current density is controlled as a function of time;
- wherein said function of time is comprised of four or more cycles, wherein each cycle independently has a first time period and a second time period, and wherein said function has a continuous first derivative with respect to time;
- where the value of said current density during said first time period is greater than zero, and the value of the current density during said second time period is less than zero, provided that the ratio, βA, which is defined as the ratio of the area bounded by the function and a line representing zero current density for said first period divided by the absolute value of the area bounded by the function and a line representing zero current density for said second period, is greater than 1, and the value of β, which is the peak cathodic current divided by the absolute value of the peak anodic current, is greater than 1;
- with the proviso that the time varying current density is a sine wave function having a D.C. offset current for four or more cycles wherein said sine wave function has a continuous first order derivative and wherein said sine wave function is symmetric about said D.C. offset current;
- wherein βA is varied for four or more consecutive cycles;
- and
- wherein the coating or electroformed article is comprised of two or more nanolayers each having a thickness greater than 0.5 nm and less than 1,000 nm.
5 more elements
A method of applying a low stress coating to a substrate, or of electroforming a low stress article, using electrodeposition comprising:
- forming a low stress coating or low stress electroformed article having a stress less than 400 MPa by applying an electrical current to said substrate to cause the electrodeposition of a composition comprising a single metal, said current having a time varying current density;
- wherein the current density is controlled as a function of time, and said function of time is comprised of three or more cycles, wherein each cycle independently has a first time period and a second time period, and wherein said function has a continuous first derivative with respect to time;
- wherein the value of said current density during said first time period is greater than zero, and the value of the current density during said second time period is less than zero, provided that the ratio, βA, which is defined as the ratio of the area bounded by the function and a line representing zero current density for said first period divided by the absolute value of the area bounded by the function and a line representing zero current density for said second period, is greater than 1;
- wherein the value of β, which is the peak cathodic current divided by the absolute value of the peak anodic current, is greater than 1;
- wherein βA is varied for three or more consecutive cycles;
- and
- wherein the coating or electroformed article is comprised of two or more nanolayers each having a thickness greater than 0.5 nm and less than 1,000 nm.
4 more elements
A method of applying a low stress coating to a substrate, or of electroforming a low stress article, using electrodeposition comprising:
- (a) providing a bath including one or more electrodepositable species;
- (b) providing a substrate or mandrel to be coated;
- (c) at least partially immersing the substrate or mandrel in the bath, the substrate or mandrel being in electrical communication with a power supply;
- and
- (d) forming a low stress coating on the substrate or low stress electroformed article on the mandrel having a stress less than 400 MPa by applying an electrical current to said substrate, said current having a time varying current density
- wherein the current density is controlled as a function of time;
- wherein said function of time is comprised of three or more cycles, wherein each cycle independently has a first time period and a second time period, and wherein said function has a continuous first derivative with respect to time;
- where the value of said current density during said first time period is greater than zero, and the value of the current density during said second time period is less than zero, provided that the ratio, βA, which is defined as the ratio of the area bounded by the function and a line representing zero current density for said first period divided by the absolute value of the area bounded by the function and a line representing zero current density for said second period, is greater than 1;
- wherein βA is varied for 3 or more consecutive cycles;
- wherein the value of β, which is the peak cathodic current divided by the absolute value of the peak anodic current, is greater than 1;
- with the proviso that the time varying current density is a sine wave function having a D.C. offset current for three or more cycles wherein said sine wave function has a continuous first order derivative and wherein said sine wave function is symmetric about said D.C. offset current;
- and
- wherein the coating or electroformed article is comprised of two or more nanolayers each having a thickness greater than 0.5 nm and less than 1,000 nm.
10 more elements
A method of applying a low stress coating to a substrate, or of electroforming a low stress article, using electrodeposition comprising:
- forming a low stress coating or low stress electroformed article having a stress less than 400 MPa by applying an electrical current to said substrate;
- wherein the current density is controlled as a function of time, and said function of time is comprised of four or more cycles, wherein each cycle independently has a first time period and a second time period, and wherein said function has a continuous first derivative with respect to time;
- wherein the value of said current density during said first time period is greater than zero, and the value of the current density during said second time period is less than zero, provided that the ratio, βA, which is defined as the ratio of the area bounded by the function and a line representing zero current density for said first period divided by the absolute value of the area bounded by the function and a line representing zero current density for said second period, is greater than 1;
- wherein the function is not identical for four or more consecutive cycles;
- wherein the value of β, which is the peak cathodic current divided by the absolute value of the peak anodic current, is greater than 1;
- and
- wherein the coating or electroformed article is comprised of two or more nanolayers each having a thickness greater than 0.5 nm and less than 1,000 nm.
4 more elements
Dependencies are inferred from the claim text.