Ball bearings comprising nickel-titanium and methods of manufacture thereof
View Patent ↗Disclosed herein is a friction reducing nickel-titanium composition. The nickel-titanium composition includes a first phase that comprises nickel and titanium in an atomic ratio of about 0.45:0.55 to about 0.55:0.45; a second phase that comprises nickel and titanium in an atomic ratio of about 0.70:0.30 to about 0.80:0.20; and a third phase that comprises nickel and titanium in an atomic ratio of about 0.52:0.48 to about 0.62:0.38. A bearing for reducing friction comprising a nickel-titanium composition comprising a first phase that comprises nickel and titanium in an atomic ratio of about 0.45:0.55 to about 0.55:0.45; a second phase that comprises nickel and titanium in an atomic ratio of about 0.70:0.30 to about 0.80:0.20; and a third phase that comprises nickel and titanium in an atomic ratio of about 0.52:0.48 to about 0.62:0.38; where the bearing is free from voids and pinholes.
1. A nickel-titanium composition comprising:
a first phase that comprises nickel and titanium in an atomic ratio of about 0.45:0.55 to about 0.55:0.45;
a second phase that comprises nickel and titanium in an atomic ratio of about 0.70:0.30 to about 0.80:0.20; and
a third phase that comprises nickel and titanium in an atomic ratio of about 0.52:0.48 to about 0.62:0.38.
2. The nickel-titanium composition of claim 1 , further comprising a fourth phase that comprises nickel and titanium in an atomic ratio of about 0.60:0.40 to about 0.67:0.33.
3. The nickel-titanium composition of claim 2 , comprising the fourth phase in an amount of up to about 5 volume percent, based on the total volume of the nickel-titanium composition.
4. The nickel-titanium composition of claim 1 , further comprising a lubricant.
5. The nickel-titanium composition of claim 1 , comprising the first phase in an amount of about 65 volume percent to about 85 volume percent, based on the total volume of the nickel-titanium composition.
6. The nickel-titanium composition of claim 1 , comprising the second phase in an amount of about 7 volume percent to about 20 volume percent, based on the total volume of the nickel-titanium composition.
7. The nickel-titanium composition of claim 1 , comprising the third phase in an amount of about 8 volume percent to about 15 volume percent, based on the total volume of the nickel-titanium composition.
8. The nickel-titanium composition of claim 1 , further comprising a lubricant.
9. The nickel-titanium composition of claim 1 , wherein the first phase is a matrix phase.
10. The nickel-titanium composition of claim 1 , wherein the second phase and the third phases are dispersed phases.
11. The nickel-titanium composition of claim 1 , wherein the nickel-titanium composition comprises grains having an average grain size of about 20 to 80 micrometers.
12. The nickel-titanium composition of claim 1 , where the first phase has an atomic ratio of nickel to titanium of 1:1.
13. The nickel-titanium composition of claim 1 , where the second phase has an atomic ratio of nickel to titanium of 3:1.
14. The nickel-titanium composition of claim 1 , where the third phase has an atomic ratio of nickel to titanium of 4:3.
15. An article comprising the composition of claim 1 .
16. The article of claim 15 , where the article is a gear, a bearing or a cam.
17. A bearing for reducing friction comprising:
a nickel-titanium composition comprising:
a first phase that comprises nickel and titanium in an atomic ratio of about 0.45:0.55 to about 0.55:0.45;
a second phase that comprises nickel and titanium in an atomic ratio of about 0.70:0.30 to about 0.80:0.20; and
a third phase that comprises nickel and titanium in an atomic ratio of about 0.52:0.48 to about 0.62:0.38; where the bearing is free from voids and pinholes.
18. The bearing of claim 17 , comprising the first phase in an amount of about 65 volume percent to about 85 volume percent, based on the total volume of the nickel-titanium composition.
19. The bearing of claim 17 , comprising the second phase in an amount of about 7 volume percent to about 20 volume percent, based on the total volume of the nickel-titanium composition.
20. The bearing of claim 17 , comprising the third phase in an amount of about 8 volume percent to about 15 volume percent, based on the total volume of the nickel-titanium composition.
21. The bearing of claim 17 , comprising a fourth phase in an amount of up to about 5 volume percent, based on the total volume of the nickel-titanium composition, where the fourth phase comprises nickel and titanium in an atomic ratio of about 0.60:0. 40 to about 0.67:0.33.