U.S. patent application number 11/577052 was filed with the patent office on 2009-05-07 for metallic mirrors formed from amorphous alloys.
Invention is credited to Steve Collier, Atakan Peker.
Application Number | 20090114317 11/577052 |
Document ID | / |
Family ID | 36565482 |
Filed Date | 2009-05-07 |
United States Patent
Application |
20090114317 |
Kind Code |
A1 |
Collier; Steve ; et
al. |
May 7, 2009 |
METALLIC MIRRORS FORMED FROM AMORPHOUS ALLOYS
Abstract
Metallic mirrors made of bulk-solidifying amorphous alloys, the
bulk-solidifying amorphous alloys providing ruggedness, lightweight
structure, excellent resistance to chemical and environmental
effects, and low-cost manufacturing, and methods of making such
metallic mirrors from such bulk-solidifying amorphous alloys are
provided.
Inventors: |
Collier; Steve; (Lake City,
FL) ; Peker; Atakan; (Aliso Viejo, CA) |
Correspondence
Address: |
CHRISTIE, PARKER & HALE, LLP
PO BOX 7068
PASADENA
CA
91109-7068
US
|
Family ID: |
36565482 |
Appl. No.: |
11/577052 |
Filed: |
October 19, 2005 |
PCT Filed: |
October 19, 2005 |
PCT NO: |
PCT/US05/38265 |
371 Date: |
December 29, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60620380 |
Oct 19, 2004 |
|
|
|
Current U.S.
Class: |
148/538 ;
148/403 |
Current CPC
Class: |
G02B 5/0808 20130101;
C22C 45/00 20130101 |
Class at
Publication: |
148/538 ;
148/403 |
International
Class: |
C22F 1/00 20060101
C22F001/00; C22C 45/00 20060101 C22C045/00 |
Claims
1. A metallic mirror comprising at least one reflective surface
made of a bulk solidifying amorphous alloy.
2. The metallic mirror of claim 1, wherein the reflective surface
is flat.
3. The metallic mirror of claim 1, wherein the reflective surface
is curved.
4. The metallic mirror of claim 1, wherein the reflective surface
further comprises a deposited dielectric coating layer.
5. The metallic mirror of claim 4, wherein reflective surface
further comprises a deposited coating layer comprised of one or
more of noble metals.
6. The metallic mirror of claim 1, wherein the amorphous alloy is
described by the following molecular formula: (Zr, Ti)a(Ni, Cu,
Fe)b(Be, Al, Si, B)c, wherein "a" is in the range of from 30 to 75,
"b" is in the range of from 5 to 60, and "c" is in the range of
from 0 to 50 in atomic percentages.
7. The metallic mirror of claim 1, wherein the amorphous alloy is
described by the following molecular formula: (Zr, Ti)a(Ni,
Cu)b(Be)c, wherein "a" is in the range of from 40 to 75, "b" is in
the range of from 5 to 50, and "c" is in the range of from 5 to 50
in atomic percentages.
8. The metallic mirror of claim 1, wherein the amorphous alloy can
sustain strains up to 1.5% or more without any permanent
deformation or breakage.
9. The metallic mirror of claim 1, wherein the amorphous alloy
amorphous alloy has a .DELTA.T of 60.degree. C. or greater.
10. The metallic mirror of claim 1, wherein the amorphous alloy has
a hardness of 7.5 Gpa and higher.
11. The metallic mirror of claim 1, wherein the reflective surface
has a surface smoothness of less than about 3 nm rms.
12. The metallic mirror of claim 1, wherein the reflective surface
has a surface smoothness of less than about 1 nm rms.
13. A metallic mirror system comprising: a reflective surface; and
a support structure, wherein at least one of the components the
mirror system is made of a bulk solidifying amorphous alloy.
14. The metallic mirror system of claim 13, wherein the reflective
surface and the support structure are a single integral structure
made of a bulk solidifying amorphous alloy.
15. The metallic mirror system of claim 13, wherein the reflective
surface and the support structure comprise separate pieces, each
made of a bulk solidifying amorphous alloy, that are joined
together into a single integral structure.
16. The metallic mirror system of claim 13, wherein the amorphous
alloy is described by the following molecular formula: (Zr,
Ti)a(Ni, Cu, Fe)b(Be, Al, Si, B)c, wherein "a" is in the range of
from 30 to 75, "b" is in the range of from 5 to 60, and "c" is in
the range of from 0 to 50 in atomic percentages.
17. The metallic mirror system of claim 13, wherein the amorphous
alloy is described by the following molecular formula: (Zr,
Ti)a(Ni, Cu)b(Be)c, wherein "a" is in the range of from 40 to 75,
"b" is in the range of from 5 to 50, and "c" is in the range of
from 5 to 50 in atomic percentages.
18. The metallic mirror system of claim 13, wherein the amorphous
alloy can sustain strains up to 1.5% or more without any permanent
deformation or breakage.
19. The metallic mirror system of claim 13, wherein the amorphous
alloy has a high fracture toughness of at least 20
ksi-in.sup.0.5.
20. The metallic mirror system of claim 13, wherein the amorphous
alloy amorphous alloy has a .DELTA.T of 60.degree. C. or
greater.
21. The metallic mirror system of claim 13, wherein the reflective
surface has a surface smoothness of less than about 1 nm rms.
22. A method of making metallic mirrors of bulk solidifying
amorphous alloy, comprising the steps of: providing a sheet
feedstock of a bulk-solidifying amorphous alloy being in a
substantially amorphous state, and having an elastic strain limit
of about 1.5% or greater and having a .DELTA.T of 30.degree. C. or
greater; heating the feedstock to around the glass transition
temperature of the bulk-solidifying amorphous alloy; shaping the
heated feedstock into a desired mirror shape; and cooling the
formed mirror to temperatures far below the glass transition
temperature.
23. The method of claim 22, wherein the .DELTA.T of the amorphous
alloy is greater than 90.degree. C.
24. The method of claim 22, wherein the elastic strain limit of the
amorphous alloy is substantially preserved during processing to be
not less than 1.5%.
25. The method of claim 22, further comprising a finishing process
selected from the group consisting of oxide removal, chemical
etching, buffing, and polishing.
26. A method of making metallic mirrors of bulk solidifying
amorphous alloy, comprising the steps of: providing a homogeneous
alloy feedstock of a bulk solidifying amorphous alloy in either an
amorphous or non-amorphous state; heating the feedstock to a
casting temperature above the melting temperature of the bulk
solidifying amorphous alloy; introducing the molten alloy into a
shape-forming mold; and quenching the molten alloy to a temperature
below the glass transition temperature of the bulk solidifying
amorphous alloy.
27. The method of claim 26, wherein the amorphous alloy has a
.DELTA.T of greater than 60.degree. C.
28. The method of claim 26, further comprising a finishing process
selected from the group consisting of oxide removal, chemical
etching, buffing, and polishing.
Description
FIELD OF THE INVENTION
[0001] The present invention is directed to metallic mirrors made
of bulk solidifying amorphous alloys and mirror systems comprising
components made of bulk solidifying amorphous alloys.
BACKGROUND OF THE INVENTION
[0002] Mirrors are optical devices designed to reflect and/or
collect light for certain purposes. For the purposes of this
disclosure, light is defined as an electromagnetic wave, which
includes, but is not limited to, the frequencies of visible light.
The most critical aspect of the mirror is the reflecting surface,
which must be extremely smooth. Generally, the surface roughness of
the reflecting surface is at the order of the wavelength of the
reflected light, and preferably less than the wavelength of the
reflected light. For high performance mirrors, surface roughness
values of less than about 3 nm "rms" are desired and for certain
mirror applications, surface roughness values of less than about
0.5 nm "rms" are preferred. The reflecting surface can be flat or
curved, such as parabolic concave shapes.
[0003] Such demanding surface smoothness can be achieved cost
effectively only with a limited number of materials. Silica-based
glass material is the leading mirror material due to the relative
ease of achieving highly smooth surfaces. Although silica-based
glasses are broadly used in mirror applications, they have severe
shortcomings due to their brittleness and extreme fragility.
Moreover, silica based glasses need a reflective coating, generally
a deposited metallic layer, which increases the processing costs
and causes further complexities.
[0004] Metals and metallic alloys provide a remedy to the main
shortcomings of silica base materials, namely the brittleness and
fragility. However, the desired smoothness of the reflective
surface cannot be readily achieved in metals. The polycrystalline
grain nature of the microstructure, the multi-phases (especially in
high strength and hardness alloy formulations), and impurities that
can degrade the reflectivity of the material are the main obstacles
for the use of conventional metals and alloys as reflective
surfaces in high performance mirror systems. For example, the cost
of achieving surface smoothness in metallic mirrors better than 3
about nm becomes very costly if at all possible. Furthermore, the
directional characteristics of crystalline structure can also
become an obstacle for achieving high surface smoothness as well as
dimensional, environmental and thermal stability of metallic
mirrors.
[0005] The mirror systems also comprise components other than the
reflecting surface. Generally, a backing structure is utilized to
support and provide durability to the reflecting surface,
especially when it is made of silica base glasses. The supporting
structure provides stiffness, stability (environmental and thermal)
when such attributes can not be achieved with the reflecting
surface itself. In certain cases, such as for the mobile and
navigational mirror systems, the weight of the mirror system needs
to be minimized and materials and structures with high-mass
efficiency are needed.
[0006] Accordingly, a need exists for novel materials to be used in
mirrors and mirror systems and also to develop novel mirror
systems, which can provide remedy to the deficiencies of incumbent
materials and structures.
SUMMARY OF THE INVENTION
[0007] The present invention is directed to a metallic mirror made
of a bulk solidifying amorphous alloy.
[0008] In another embodiment of the invention, the metallic mirror
has a flat reflecting surface
[0009] In yet another embodiment of the invention, the metallic
mirror comprises a curved reflecting surface.
[0010] In still yet another embodiment of the invention, the
metallic mirror comprises a reflecting surface and a back-structure
for supporting the reflecting surface.
[0011] In still yet another embodiment of the invention, the
metallic mirror comprises a reflecting surface and a back-structure
as a single integral structure.
[0012] In still yet another embodiment of the invention, the
metallic mirror comprises a reflecting surface and a back-structure
joined together.
[0013] In still yet another embodiment of the invention, the
reflecting surface of the metallic mirror comprises a deposited
dielectric coating layer.
[0014] In still yet another embodiment of the invention, the
reflecting surface of the metallic mirror comprises a deposited
coating layer comprised of one or more of noble metals.
[0015] In still yet another embodiment of the invention, the
amorphous alloy is described by the following molecular formula:
(Zr, Ti)a(Ni, Cu, Fe)b(Be, Al, Si, B)c, wherein "a" is in the range
of from 30 to 75, "b" is in the range of from 5 to 60, and "c" is
in the range of from 0 to 50 in atomic percentages
[0016] In still yet another embodiment of the invention, the
amorphous alloy is described by the following molecular formula:
(Zr, Ti)a(Ni, Cu)b(Be)c, wherein "a" is in the range of from 40 to
75, "b" is in the range of from 5 to 50, and "c" is in the range of
from 5 to 50 in atomic percentages.
[0017] In still yet another embodiment of the invention, the
amorphous alloy can sustain strains up to 1.5% or more without any
permanent deformation or breakage.
[0018] In still yet another embodiment of the invention, the bulk
solidifying amorphous alloy has a high fracture toughness of at
least 20 ksi-in.sup.0.5.
[0019] In still yet another embodiment of the invention, the bulk
solidifying amorphous alloy has a .DELTA.T of 60.degree. C. or
greater.
[0020] In still yet another embodiment of the invention, the bulk
solidifying amorphous has a hardness of 7.5 Gpa and higher.
[0021] In another alternative embodiment, the invention is also
directed to methods of manufacturing metallic mirrors from
bulk-solidifying amorphous alloys.
DESCRIPTION OF THE INVENTION
[0022] The current invention is directed to metallic mirrors made
of bulk-solidifying amorphous alloys, the bulk-solidifying
amorphous alloys providing ruggedness, lightweight structure,
excellent resistance to chemical and environmental effects, and
low-cost manufacturing for highly smooth reflecting surfaces.
Another object of the current invention is a method of making
metallic mirrors from such bulk-solidifying amorphous alloys.
[0023] Bulk solidifying amorphous alloys are a recently discovered
family of amorphous alloys, which can be cooled at substantially
lower cooling rates, of about 500 K/sec or less, and substantially
retain their amorphous atomic structure. As such, they can be
produced in thicknesses of 1.0 mm or more, substantially thicker
than conventional amorphous alloys, which are typically limited to
thicknesses of 0.020 mm, and which require cooling rates of
10.sup.5 K/sec or more. U.S. Pat. Nos. 5,288,344; 5,368,659;
5,618,359; and 5,735,975, the disclosures of which are incorporated
herein by reference in their entirety, disclose such bulk
solidifying amorphous alloys.
[0024] A family of bulk solidifying amorphous alloys can be
described as (Zr, Ti)a(Ni, Cu, Fe)b(Be, Al, Si, B)c, where a is in
the range of from 30 to 75, b is in the range of from 5 to 60, and
c is in the range of from 0 to 50 in atomic percentages.
Furthermore, these basic alloys can accommodate substantial amounts
(up to 20% atomic, and more) of other transition metals, such as
Nb, Cr, V, Co. A preferable alloy family is (Zr, Ti)a(Ni,
Cu)b(Be)c, where a is in the range of from 40 to 75, b is in the
range of from 5 to 50, and c is in the range of from 5 to 50 in
atomic percentages. Still, a more preferable composition is (Zr,
Ti)a(Ni, Cu)b(Be)c, where a is in the range of from 45 to 65, b is
in the range of from 7.5 to 35, and c is in the range of from 10 to
37.5 in atomic percentages. Another preferable alloy family is
(Zr)a(Nb, Ti)b(Ni, Cu)c(Al)d, where a is in the range of from 45 to
65, b is in the range of from 0 to 10, c is in the range of from 20
to 40 and d is in the range of from 7.5 to 15 in atomic
percentages.
[0025] Another set of bulk-solidifying amorphous alloys are ferrous
metals (Fe, Ni, Co) based compositions. Examples of such
compositions are disclosed in U.S. Pat. No. 6,325,868 and in
publications to (A. Inoue et. al., Appl. Phys. Lett., Volume 71, p
464 (1997)), (Shen et. al., Mater. Trans., JIM, Volume 42, p 2136
(2001)), and Japanese patent application 2000126277 (Publ. No.
2001303218 A), all of which are incorporated herein by reference.
One exemplary composition of such alloys is Fe72Al5Ga2P11C6B4.
Another exemplary composition of such alloys is
Fe72Al7Zr10Mo5W2B15. Although, these alloy compositions are not
processable to the degree of the Zr-base alloy systems, they can
still be processed in thicknesses of 1.0 mm or more, sufficient
enough to be utilized in the current invention.
[0026] Bulk-solidifying amorphous alloys have typically high
strength and high hardness. For example, Zr and Ti-base amorphous
alloys typically have yield strengths of 250 ksi or higher and
hardness values of 450 Vickers or higher. The ferrous-base version
of these alloys can have yield strengths up to 500 ksi or higher
and hardness values of 1000 Vickers and higher. As such, these
alloys display excellent strength-to-weight ratio especially in the
case of Ti-base and Fe-base alloys. Furthermore, bulk-solidifying
amorphous alloys have good corrosion resistance and environmental
durability, especially the Zr and Ti based alloys. Amorphous alloys
generally have, high elastic strain limit approaching up to 2.0%,
much higher than any other metallic alloy.
[0027] In general, crystalline precipitates in bulk amorphous
alloys are highly detrimental to the properties of amorphous
alloys, especially to the toughness and strength of these alloys,
and as such it is generally preferred to minimize the volume
fraction of these precipitates. However, there are cases in which,
ductile crystalline phases precipitate in-situ during the
processing of bulk amorphous alloys, which are indeed beneficial to
the properties of bulk amorphous alloys, especially to the
toughness and ductility of the alloys. Such bulk amorphous alloys
comprising such beneficial precipitates are also included in the
current invention. One exemplary case is disclosed in (C. C. Hays
et. al, Physical Review Letters, Vol. 84, p 2901, 2000), which is
incorporated herein by reference.
[0028] As a result of the use of these bulk-solidifying amorphous
alloys, the metallic mirrors of the present invention have
characteristics that are much improved over conventional metallic
mirrors made of ordinary metallic materials. The surprising and
novel advantages of using bulk-solidifying amorphous alloys in
producing metallic mirrors will be described in various embodiments
below.
[0029] First, the unique amorphous atomic structure, of the bulk
solidifying amorphous alloys provide a featureless microstructure,
wherein high surface smoothness can be achieved substantially
better than conventional metallic alloys. The general obstacles to
high surface finish, such as poly-crystalline microstructure, are
not applicable. The inventors discovered that the surfaces of
exemplary bulk solidifying amorphous alloys can be polished to very
high degrees of smoothness. Initial trials demonstrate that surface
smoothness of 3 nm rms can be readily achieved and surface
smoothness of less than 1 nm rms is within practicality. Moreover,
such high surface smoothness can be achieved over large areas more
than several inches square. Accordingly, the quality of the
reflective surfaces of bulk solidifying amorphous alloys
substantially become better than conventional metals and
alloys.
[0030] Secondly, the combination of high strength and high
strength-to-weight ratio of the bulk solidifying amorphous alloys
significantly reduces the overall weight and bulkiness of the
metallic mirrors of the current invention, thereby allowing for the
reduction of the thickness of these metallic mirrors without
jeopardizing the structural integrity and operation of mirror
systems into which these metallic mirrors are integrated. The
ability to fabricate metallic mirrors with thinner walls is also
important in reducing the bulkiness of the mirror system and
increasing the efficiency per -volume of the mirror system. This
increased efficiency is particularly useful for the application of
mirror systems in mobile devices and equipment, such as in
navigational instruments and space vehicles.
[0031] Although other materials, such as silica base glasses, are
considered in these reflecting surfaces, there are major
fabrication and assembly deficiencies with those materials. For
example, silica based glasses lack any flexibility and are
therefore actually quite fragile. Other conventional metallic
alloys, although not fragile, however, are prone to permanent
deformation, denting and scratching due to low hardness values. The
very large surface area and very small thicknesses of metallic
mirrors makes such problems even more significant. However,
bulk-solidifying amorphous alloys have reasonable fracture
toughness, on the order of 20 ksi-sqrt(in), and high elastic strain
limit, approaching 2%. Accordingly, high flexibility can be
achieved without permanent deformation and denting of the metallic
mirror and high hardness of bulk solidifying amorphous alloys
provide better resistance against scratching of the reflecting
surface. As such, metallic mirrors made of bulk-solidifying
amorphous alloys can be readily handled during fabrication and
assembly, reducing the cost and increasing the performance of the
mirror system.
[0032] As discussed, bulk solidifying amorphous alloys have very
high elastic strain limits, typically around 1.5% or higher. This
is an important characteristic for the use and application of
mirror system metallic mirrors. Specifically, high elastic strain
limits are preferred for devices mounted in mobile devices, or in
other applications subject to mechanical loading or vibration. A
high elastic strain limit allows the metallic mirror to take even
more intricate shape and to be thinner and lighter, high elastic
strain limits also allow the metallic mirrors to sustain loading
and flexing without permanent deformation or destruction of the
device, especially during assembly.
[0033] In addition, metallic mirrors made of bulk solidifying
amorphous alloy also have good corrosion resistance and high
inertness. The high corrosion resistance and inertness of these
materials are useful for preventing the metallic mirrors from being
decayed by undesired chemical reactions between the metallic mirror
and the environment of the mirror system. The inertness of bulk
solidifying amorphous alloy is also very important to the life of
the mirror system because it does not tend to decay the reflective
nature of the reflecting surface.
[0034] Another aspect of the invention is the ability to make
metallic mirrors with isotropic characteristics. Generally
non-isotropy in metallic articles causes degraded performance for
those portions of metallic articles that require precision fit,
such as in the contact surfaces of the formed metallic mirrors due
to variations in temperature, mechanical forces, and vibration
experienced across the article. Moreover, the non-uniform response
of ordinary metals in various directions would also require
extensive design margins to compensate, and as such would result in
heavy and bulky structures. Accordingly, the isotropic response of
the metallic mirrors in accordance with the present invention is
crucial, at least in certain designs, given the intricate and
complex patterns and the associated large surface areas and very
small thicknesses of the metallic mirrors, as well as the need to
utilize high strength construction material. For example, castings
of ordinary alloys are typically poor in mechanical strength and
are distorted in the case of large surface area and very small
thickness. Accordingly, using metallic alloys for casting such
large surface areas with high tolerance in flatness (or precisely
curved shapes) is not generally feasible. In addition, for ordinary
metallic alloys, extensive rolling operations would be needed to
produce the metallic mirror sheet in the desired flatness and with
the desired high strength. However, in this case the rolled
products of ordinary high-strength alloys generate strong
orientation, and as such lack the desirable isotropic properties.
Indeed, such rolling operations typically result in highly oriented
and elongated crystalline grain structures in metallic alloys
resulting in highly non-isotropic material. In contrast,
bulk-solidifying amorphous alloys, due to their unique atomic
structure lack any microstructure as observed in crystalline and
grainy metal, and as a result articles formed from such alloys are
inherently isotropic.
[0035] Another function of the metallic mirror is to provide
structural rigidity and complex patterns of back structure to
provide a stiff support. The high strength, high elastic strain
limit and high surface finishes of the bulk amorphous alloys allow
for the ready production of metallic mirrors with seals of
relatively high integrity back structures. As discussed below, the
near-to-net shape forming ability of the bulk solidifying alloys
allows the, use design features, such as ribs and ridges, to
improve the stiffness and structural integrity of the support
structures and mirror systems.
[0036] Another object of the invention is providing a method to
produce metallic mirrors in net-shape form from bulk solidifying
amorphous alloys. By producing metallic mirrors in net-shape form
manufacturing costs can be significantly reduced while still
forming metallic mirrors with good flatness, intricate surface
features comprising precision curves, and high surface finish on
the reflecting areas.
[0037] One exemplary method of making such metallic mirrors
comprises the following steps: [0038] 1) Providing a sheet
feedstock of amorphous alloy being substantially amorphous, and
having an elastic strain limit of about 1.5 % or greater and having
a .DELTA.T of 30.degree. C. or greater; [0039] 2) Heating the
feedstock to around the glass transition temperature; [0040] 3)
Shaping the heated feedstock into the desired shape; and [0041] 4)
Cooling the formed sheet to temperatures far below the glass
transition temperature.
[0042] Herein, .DELTA.T is given by the difference between the
onset of crystallization temperature, Tx, and the onset of glass
transition temperature, Tg, as determined from standard DSC
(Differential Scanning Calorimetry) measurements at typical heating
rates (e.g. 20.degree. C./min).
[0043] Preferably .DELTA.T of the provided amorphous alloy is
greater than 60.degree. C., and most preferably greater than
90.degree. C. The provided sheet feedstock can have about the same
thickness as the average thickness of the final metallic mirror.
Moreover, the time and temperature of the heating and shaping
operation is selected such that the elastic strain limit of the
amorphous alloy is substantially preserved to be not less than
1.0%, and preferably not being less than 1.5%. In the context of
the invention, temperatures around glass transition means the
forming temperatures can be below glass transition, at or around
glass transition, and above glass transition temperature, but
always at temperatures below the crystallization temperature Tx.
The cooling step is carried out at rates similar to the heating
rates at the heating step, and preferably at rates greater than the
heating rates at the heating step. The cooling step is also
achieved preferably while the forming and shaping loads are still
maintained.
[0044] Upon the finishing of the above-mentioned fabrication
method, the shaped metallic mirror can be subjected further surface
treatment operations as desired such as to remove any oxides on the
surface. Chemical etching (with or without masks) can be utilized
as well as light buffing and polishing operations to provide
improvements in surface finish so that high quality reflectivity
and surface matching with other components can be achieved.
[0045] Another exemplary method of making metallic mirrors in
accordance with the present invention comprises the following
steps: [0046] 1) Providing a homogeneous alloy feedstock of
amorphous alloy (not necessarily amorphous); [0047] 2) Heating the
feedstock to a casting temperature above the melting temperatures;
[0048] 3) Introducing the molten alloy into shape-forming mold; and
[0049] 4) Quenching the molten alloy to temperatures below glass
transition.
[0050] Bulk amorphous alloys retain their fluidity from above the
melting temperature down to the glass transition temperature due to
the lack of a first order phase transition. This is in direct
contrast to conventional metals and alloys. Since, bulk amorphous
alloys retain their fluidity, they do not accumulate significant
stress from their casting temperatures down to below the glass
transition temperature and as such dimensional distortions from
thermal stress gradients can be minimized. Accordingly, metallic
mirrors with large surface area and small thickness can be produced
cost-effectively.
[0051] Although specific embodiments are disclosed herein, it is
expected that persons skilled in the art can and will design
alternative amorphous alloy metallic mirrors and methods to produce
the amorphous alloy metallic mirrors that are within the scope of
the following claims either literally or under the Doctrine of
Equivalents.
* * * * *