Electrodeposition of indium-thallium shape memory alloys

• US 5,203,931 A
• Filed: 09/20/1991
• Issued: 04/20/1993
• Est. Priority Date: 09/20/1991
• Status: Expired due to Fees

• Current Assignee: Curators of the University of Missouri (University of Missouri)
• Original Assignee: Curators of the University of Missouri (University of Missouri)
• Inventors: O'Keefe, Thomas J.
• Primary Examiner(s): WYSZOMIERSKI, GEORGE P
• Application Number:
  US07/763,343
• Time in Patent Office: 578 Days
• Field of Search: 205/104, 205/238, 148/402, 148/563, 148/518
• US Class Current: 148/518
• CPC Class Codes: C25D 3/56 of alloys
• CPC Class Codes: C25D 5/18 Electroplating using modulated, pulsed or reversing current
• CPC Class Codes: C25D 5/611 Smooth layers

Abstract

A process for preparing an indium-thallium alloy which exhibits shape memory transformation at a temperature greater than that temperature at which shape memory transformation would occur for a thermally prepared alloy of the same composition. The process includes providing an article for use as a cathode, providing an electrolyte which comprises indium and thallium ions, and electrodepositing an indium-thallium alloy having between about 21 and about 35 atomic percent thallium onto the article. A process for preparing an article constructed of an electrodeposited indium-thallium alloy which exhibits shape memory effect. An electrodeposited indium-based shape memory alloy.

Claims

1. A process for preparing an indium-thallium alloy which exhibits shape memory transformation at a temperature greater than that temperature at which shape memory transformation would occur for a thermally prepared alloy of the same composition, the process comprising:

providing an article for use as a cathode;

providing an electrolyte by dissolving indium sulfate and thallium sulfate in an acidic solution;

electrodepositing the indium-thallium alloy onto the article, the indium-thallium alloy comprising between about 21 and about 35 atomic percent thallium.

2. A process as set forth in claim 1 wherein said article for use as a cathode has a generally rectangular conformation.

3. A process as set forth in claim 1 wherein said article for use as a cathode is a polyhedral body.

4. A process as set forth in claim 1 wherein said article for use as a cathode is an electronic circuit.

5. A process as set forth in claim 1 wherein said electrolyte is prepared by dissolving, in a sulfuric acid solution, indium sulfate in the range of from about 30 g/l to about 50 g/l and thallium sulfate in the range of from about 1.0 g/l to about 3.0 g/l.

6. A process as set forth in claim 1 wherein said electrolyte is maintained in the range of from about 20°

C. to about 50°

C.

7. A process as set forth in claim 1 wherein said indium-thallium alloy comprises between about 23 and about 28 atomic percent thallium.

8. A process for preparing an article constructed of an electrodeposited indium-thallium alloy which exhibits shape memory effect, the process comprising:

providing an electrodeposited indium-thallium alloy having between about 21 and about 35 atomic percent thallium, said alloy exhibiting shape memory transformation at a temperature greater than that at which shape memory transformation would occur for a thermally prepared alloy of the same composition;

establishing a first configuration of the article at a first higher temperature, said first higher temperature being a temperature greater than the martensitic transformation temperature for the alloy;

establishing a second configuration by deforming the article at a second lower temperature, said second lower temperature being a temperature less than the martensitic transformation temperature for the alloy.

9. A process as set forth in claim 8 wherein said second lower temperature is between about 5°

C. and about 30°

C.

10. A process as set forth in claim 8 wherein said second lower temperature is between about -50°

C. and about 5°

C.

11. A process for preparing an indium-thallium alloy which exhibits shape memory transformation at a temperature greater than that temperature at which shape memory transformation would occur for a thermally prepared alloy of the same composition, the process comprising:

providing an article for use as a cathode;

providing an electrolyte which comprises indium and thallium ions;

electrodepositing the indium-thallium alloy onto the article by providing pulsed current to the electrolyte, the indium-thallium alloy comprising between about 21 and about 35 atomic percent thallium.

12. A process as set forth in claim 11 wherein said pulsed current has a peak current density of between about 6 and about 40 mA/cm².

13. A process as set forth in claim 11 wherein said pulsed current has a duty cycle of between about 30% and about 70%.

14. A process as set forth in claim 11 wherein said indium-thallium alloy comprises between about 23 and 28 atomic percent thallium.