Claims
- 1. An alloy with ultrafine crystal grains, excellent in corrosion resistance, having a composition represented by the following general formula:
- M.sub.100-x-y-z-.alpha.-.beta.-.gamma. A.sub.x Si.sub.y B.sub.z M'.sub..alpha. M".sub..beta. X.sub..gamma. (atomic %)
- wherein M is greater than 0 atomic % and represents at least one element selected from the group consisting of Fe, Co and Ni; A represents at least one element selected from the group consisting of Cu, Ag and Au; M' represents at least one element selected from the group consisting of Nb, Mo, Ta, Ti, Zr, Hf, V, Cr and W; M" represents at least one element selected from the group consisting of Mn, Al, platinum group elements, Sc, Y, rare earth elements, Zn, Sn and Re; X represents at least one element selected from the group consisting of C, Ge, P, Ga, Sb, In, Be and As, and x, y, z, .alpha., .beta., and .gamma. respectively satisfy 0<x<10, 0<y<30, 0<z<25, 0<y+z<30, 1<.alpha.<20, 0<.beta.<20, and 0<.gamma.<20;
- wherein at least 50% of the alloy structure is occupied by ultrafine crystal grains,
- wherein said alloy has a surface layer containing hydroxide components in a total proportion of 65% or more based on oxide components, and
- wherein said surface layer is formed by
- (1) heat-treating an amorphous alloy to provide it with ultrafine crystal grains, and then heat-treating the resulting alloy with ultrafine crystal grains at 250.degree.-700.degree. C. for 5 minutes to 24 hours in an inert gas atmosphere containing 0.001-1 volume % of oxygen and 1-100 ppm of steam; or
- (2) heat-treating an amorphous alloy at 450.degree.-700.degree. C. for 10 minutes to 24 hours in an inert gas atmosphere containing 0.0001-1 volume % of oxygen and 1-100 ppm of steam.
- 2. The alloy according to claim 1, wherein said alloy is an Fe-based alloy and has a surface layer containing compounds of Fe.sup.2+ and Fe.sup.3+, and wherein Fe.sup.0 spectrum is observable in said alloy by X-ray photoelectron spectroscopy.
- 3. The alloy according to claim 1, wherein said alloy contains Si and has a surface layer containing a compound of Si.sup.4+, and wherein the ratio of Si.sup.4+ peaks to an integrated value of entire 2p spectrum of Si is more than 55% by X-ray photoelectron spectroscopy.
- 4. The alloy according to claim 2, wherein said alloy contains Si and has a surface layer containing a compound of Si.sup.4+, and wherein the ratio of Si.sup.4+ peaks to an integrated value of entire 2p spectrum of Si is more than 55% by X-ray photoelectron spectroscopy.
- 5. The alloy according to claim 1, wherein said surface layer contains an oxide of at least one element selected from the group consisting of Ta, Nb and Cr.
- 6. The alloy according to claim 2, wherein said surface layer contains an oxide of at least one element selected from the group consisting of Ta, Nb and Cr.
- 7. The alloy according to claim 3, wherein said surface layer contains an oxide of at least one element selected from the group consisting of Ta, Nb and Cr.
- 8. The alloy according to claim 4, wherein said surface layer contains an oxide of at least one element selected from the group consisting of Ta, Nb and Cr.
- 9. The alloy according to claim 1, wherein said surface layer contains an oxide of at least one element selected from the group consisting of Zr, Hf and W.
- 10. The alloy according to claim 2, wherein said surface layer contains an oxide of at least one element selected from the group consisting of Zr, Hf and W.
- 11. The alloy according to claim 3, wherein said surface layer contains an oxide of at least one element selected from the group consisting of Zr, Hf and W.
- 12. The alloy according to claim 4, wherein said surface layer contains an oxide of at least one element selected from the group consisting of Zr, Hf and W.
- 13. The alloy according to claim 1, wherein the corrosion rate of said alloy in a 0.1-kmol.m.sup.-3 NaCl aqueous solution is 1.times.10.sup.-8 kg.m.sup.-2.s.sup.-1 or less.
- 14. The alloy according to claim 2, wherein the corrosion rate of said alloy in a 0.1-kmol.m.sup.-3 NaCl aqueous solution is 1.times.10.sup.-8 kg.m.sup.-2.s.sup.-1 or less.
- 15. The alloy according to claim 3, wherein the corrosion rate of said alloy in a 0.1-kmol.m.sup.-3 NaCl aqueous solution is 1.times.10.sup.-8 kg.m.sup.-2.s.sup.-1 or less.
- 16. The alloy according to claim 1, wherein said alloy comprises ultrafine crystal grains having an average grain size of 500 .ANG. or less.
- 17. The alloy according to claim 2, wherein said alloy comprises ultrafine crystal grains having an average grain size of 500 .ANG. or less.
- 18. The alloy according to claim 3, wherein said alloy comprises ultrafine crystal grains having an average grain size of 500 .ANG. or less.
Priority Claims (1)
Number |
Date |
Country |
Kind |
4-235467 |
Sep 1992 |
JPX |
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CROSS-REFERENCE TO RELATED APPLICATION
This is a Continuation of application Ser. No. 08/314,771 filed Sep. 29, 1994 abandoned, which is is a continuation-in-part of application U.S. Ser. No. 08/115,777, filed Sep. 3, 1993, now abandoned.
US Referenced Citations (2)
Number |
Name |
Date |
Kind |
3902888 |
Aonuma et al. |
Sep 1975 |
|
4881989 |
Yoshizawa et al. |
Nov 1989 |
|
Continuations (1)
|
Number |
Date |
Country |
Parent |
314771 |
Sep 1994 |
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Continuation in Parts (1)
|
Number |
Date |
Country |
Parent |
115777 |
Sep 1993 |
|