JPH0428869A - Production of surface modified zirconium alloy - Google Patents

Abstract

PURPOSE:To produce a Zr alloy in which surface characteristics, such as corrosion resistance and wear resistance, are improved by implanting elements, such as Cr, on the surface of a Zr alloy by means of ion implantation, and carrying out heat treatment in a nonoxidizing atmosphere. CONSTITUTION:One or >=2 elements selected from Cr, Fe, Sn, Ni, Ti, Hf, C, N, Si, W, and Al are implanted by means of ion implantation on the surface of a Zr alloy (zircaloy-2, zircaloy-4, etc.) or in the vicinity of the above surface. At this time, the amount (concentration) of the implanted elements is about 10<13>-10<21>ions/cm<2> and the energy of the implanted ions is >= about several kiloelectron volts, and, by implanting ions while regulating acceleration energy to about several tens - hundreds kiloelectron volts, a concentrated layer of about 0.1mu depth where the concentration of the implanted elements is maximal is formed. By this method, the Zr alloy suitably usable, e.g. for fuel clad pipe material for light water reactor can be obtained.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a method for manufacturing a surface-modified zirconium alloy, and more specifically, to a method for manufacturing a surface-modified zirconium alloy. It can be used to fit various nuclear reactor-related materials such as lower end plugs, etc. 1 It is suitable for use in various fields of application, especially in the field of manufacturing high-performance zirconium alloys that require surface properties such as high corrosion resistance and wear resistance. The present invention relates to a method for producing a surface-modified zirconium alloy that can be suitably used.

[Prior Art and Problems to be Solved by the Invention] Zirconium alloys have a significantly small thermal neutron absorption cross section and excellent mechanical strength and corrosion resistance, so they are used in boiling water reactors (BWRs) and pressurized water reactors. type light water reactor (PWR)
) is widely used in various fields including the nuclear reactor plant field, such as fuel cladding tube materials and reactor core structural materials.

Zircaloy-2 and Zircaloy-4 having the compositions shown in Table 1 are known as representative zirconium alloys.

Of these, Zircaloy-2 is mainly used in boiling water reactors (BW).
On the other hand, Zircaloy-4 is used for fuel channel boxes, fuel spacers, etc. of BWRs, and for pressurized water reactors (PWRs).
It is used for fuel cladding tube materials, upper and lower end plugs, simple control rod guide tubes, and guide tubes for in-core instrumentation.

In these zirconium alloy BWR structural members, spotty white corrosion products called Noschler corrosion occur on the surface, while in PWR members uniform corrosion occurs, or in the current operation of practical nuclear reactors. Under these conditions, this phenomenon is not a problem and both components perform their functions satisfactorily.

However, in the future, it will be necessary to adequately deal with the longer residence time of these components in the reactor and harsher usage conditions due to long-term operation of nuclear reactors, higher burnup, etc., or to improve the economic efficiency of thermal neutrons. Conventional zirconium alloys such as Zircaloy are insufficient to meet the strict demands of thinning structural members for improved performance, and there is a need to further improve their performance, especially their surface properties such as corrosion resistance. .

In consideration of these trends in the field of nuclear reactor components, various attempts have been made to adjust the composition of Zircaloy, improve performance through thermal history treatment, and develop new zirconium alloys.

For example, Auzenite 0.5, Auzenite 1.0, 2 which is a zirconium alloy containing niobium (Nb)
r-2.5%Nb, Zr-1.0%Nb, etc. have superior nodular corrosion resistance compared to the above-mentioned Zircaloy-2 and Zircaloy-4.Results of in-furnace observation and out-of-furnace corrosion tests show that It has been revealed from. Among these, Zr-2,5%Nb alloy, which is a Zr-Nb based alloy, is used as pressure tubes in CANDU furnaces in Canada. In addition, EXCEL alloy (Z) is a material with improved mechanical properties and irradiation growth.
r -2,5~4.0%S n -0,5~1.5%M
o -0.5~1.5%Nb)
134:104). Furthermore, 5canuk alloy [Zr-0.25~1.5%Nb-] is said to have better corrosion resistance than Zircaloy alloy.
0,025~0.20% Sn -0,02~1.0%
(Cr+Mo), or Z r −0,45 to 1.
40%N b -0.04~(1.1%Sn0.25~
0.5% (Cr+Mo)-0-7~I-8%(N
b+Cr+Mo)] is known (Unexamined Japanese Patent Publication No. 50-14
8213), in addition, zr-0.5~5%N
B alloys are also known (Japanese Patent Application Laid-open No. 47-42220).

However, these Nb-containing zirconium alloys
Other than the Zr-2,5%Nb alloy, there is little experience, and even this Zr-2,5%Nb alloy has the disadvantage that the corrosion resistance of the welded part tends to deteriorate. In addition, in such Nb-containing zirconium alloys, generally,
(2) Nb is rare, and (2) increasing the Nb concentration in the entire material causes new problems such as lower ductility and manufacturing (processing) difficulty.

As a means of alleviating these problems, it has been proposed to provide a concentrated layer of Nb on or near the surface of the zirconium alloy by ion implantation, coating/thermal diffusion, etc. (Japanese Patent Laid-Open No. 61-243175). In this way, the method of adjusting the composition of the surface or near the surface of the material rather than the entire material can improve the surface properties without deteriorating the bulk properties of the base material itself, and moreover, depending on the method used, This method is considered to be an extremely effective method in that it is possible to easily control the surface characteristics of a desired portion of the surface.

In fact, according to item (1) above, an improved zirconium alloy with excellent mechanical strength and improved nodular corrosion resistance is obtained with almost no reduction in ductility.

However, in this surface-modified zirconium alloy by the addition of Nb, although Nb is used only in the surface layer to reduce costs, the above-mentioned problem (1) has not been essentially solved, and (1) Since the adjustment of the surface composition is limited to the use of Nb, it is difficult to satisfy the optimum characteristics unique to each material such as various nuclear reactor structural materials, and the range of use is limited. There are some problems.

On the other hand, there are also attempts to improve the surface properties of zirconium alloys by using various elemental components to adjust the surface composition.

For example, ■Japanese Unexamined Patent Publication No. 61-279675 describes the periodic table Va, Vb, VIa and ■b excluding nitrogen and oxygen.
A zirconium alloy having an oxygen-deficient oxide layer on its surface containing at least one element selected from group elements has been disclosed. Also, ■Japanese Patent Publication No. 62-50485
In the publication, the periodic table ■,
1, 1 of the elements of the ■, ■, ■, and ■ groups! or 2
A zirconium alloy member having a zirconium oxide film containing 0.1 to 50 atomic % of zirconium oxide is disclosed.

These zirconium alloys with an oxide layer on the surface of This was proposed with the intention of improving the disadvantage of increasing the film thickness of the diffusion layer and promoting Noschler corrosion due to this. An oxide layer is formed by a method such as autoclave treatment, and then the predetermined element is introduced into the oxide layer by an ion implantation method (■) or a thermal diffusion method (@) to adjust the composition and improve its characteristics. It's improving.

These zirconium alloys with oxide layers whose compositions of ■ and @ have been adjusted have improved surface properties such as corrosion resistance without deteriorating bulk performance. It is advantageous to be able to provide a variety of zirconium alloys.

However, in these zirconium alloys (1) and (2), it is necessary to form an oxide layer on the zirconium alloy before introducing the predetermined additive elements.
There are disadvantages such as the manufacturing process is complicated and the manufacturing cost is high.

By the way, zirconium alloys with an oxide layer on the surface are generally used as fuel cladding materials for BWRs, while for PWRs only zirconium alloys without any oxide layers are used. There is. This is due to differences in the approach to corrosion protection for the coolant in the inner furnace tube.

Therefore, when dealing with a zirconium alloy material that does not have an oxide layer, it is not possible to apply the techniques (1) and (2) above, and the desired performance cannot be achieved even without forming an oxide layer. If so, it would be advantageous to improve the surface properties such as corrosion resistance without providing an oxide layer from the viewpoint of simplifying the manufacturing process and reducing manufacturing costs.

Therefore, surface modification (surface layer composition adjustment method), that is also Nb
If a method of surface modification by injection of various elements other than those mentioned above could be developed, the problems of the previous steps would be solved, and high-performance zirconium alloys could be produced which are advantageous for various uses such as materials related to raw material reactors. It can be thought that what you get is what you get.

The present invention has been made in view of the above circumstances.

The purpose of the present invention is to improve the corrosion resistance, wear resistance, and other surface properties of various conventional zirconium alloys, particularly the Noschler corrosion resistance and - The object of the present invention is to provide a method for producing a surface-modified zirconium alloy in which surface properties such as corrosion resistance such as corrosion resistance are sufficiently improved without impairing bulk properties.

[Means for Solving the Problem] In order to solve the above-mentioned problems, the present inventor uses various zirconium alloys (particularly zirconium alloys that have not been treated to provide an oxidized layer) as a base material, and The corrosion and wear resistance of the zirconium alloy base material is improved without impairing the bulk properties of the zirconium alloy base material by injecting specific elements into the surface or near the surface of the material using ion implantation, followed by heat treatment in a non-oxidizing atmosphere. The present invention was completed based on the discovery that it is possible to effectively improve the surface properties such as the following.

That is, the present invention provides Cr, Fe, Sn, Ni, Ti, Hf, C on the surface or near the surface of the zirconium alloy.
, N, Si, W, and one or two types selected from A sentence.
The present invention is a method for producing a surface-modified zirconium alloy, which is characterized in that more than one element is implanted into columns by an ion implantation method, and the zirconium alloy after the ion implantation is heat treated in a non-oxidizing atmosphere.

In the method of the present invention, used as the raw material base material,
That is, in order to distinguish the zirconium alloy used as the raw material base material from the zirconium alloy subjected to the ion implantation method, which is a step of surface property improvement treatment, from the zirconium alloy with improved surface properties of the present invention, As the zirconium alloy base material (sometimes referred to as the base material), zirconium alloys having various compositions such as known zirconium alloys can be used. Typically, 5n
(1-2% by weight), F e (0.05-0.:1
(wt%), Cr (0-0.2wt%), Ni (0
Zircaloy-2, Zircaloy-4 and the like can be specifically exemplified. In addition to these, various Z r -2,5%Nb
type, various Zr-1%Nb type, various EXCE
In order to ensure the mechanical strength of L alloy, various 5canuk alloys, or zirconium base, Mo (0,1~
21% by weight), Mn (0.1-6.4% by weight),
Nb (0.1~17.5% by weight), A text (0.1~2
Examples include martensitic zirconium alloys containing at least one of Fe (0.1 to 6.4% by weight) and Auzenite.

Among these zirconium alloys with various compositions, which one to use as the base material should be selected appropriately by considering the use and cost of the zirconium alloy of the present invention. It is preferable to use a material that does not contain expensive elements, or even if it does contain it, the content is such that it does not pose a cost problem.

Examples of materials that can be particularly suitably used as the base material include Zircaloy-2 and Zircaloy-4.

These zirconium alloy base materials may be subjected to a surface treatment, such as one in which an oxide layer is formed on or near the surface by performing an oxide layer formation treatment in advance, or the manufacturing process is normally carried out. From the viewpoint of simplicity and manufacturing cost, it is preferable to use a material that is not subjected to an oxidation layer formation treatment.

By the way, the surface of a zirconium alloy always has an oxide film in the air even if no oxide layer formation treatment is performed. In the present invention, of course, a zirconium alloy base material having an oxide film that is normally formed without undergoing such an oxide layer forming treatment is suitably used as the zirconium alloy base material to be subjected to the ion implantation. It comes.

In other words, in the present invention, before performing the ion implantation process, the zirconium alloy base material is subjected to an autocrane process or the like as described in, for example, JP-A-61-279675 and JP-A-62-50485. It is not always necessary to form an oxide layer by other methods (oxygen-deficient oxide layer, oxygen diffusion layer, or oxide film); rather, as mentioned above, such oxidation It is preferable to use a substrate that has not been subjected to layer formation treatment.

Note that, if necessary, the base material may be obtained by removing the oxidized layer such as the oxide film that is normally formed as described above by any means.

There are no particular restrictions on the shape of the base material used, and raw materials that have not been subjected to forming processing, intermediate materials that are in the process of being processed, processed parts such as materials for raw material furnaces, and even raw materials that have undergone processing such as materials for raw material furnaces, etc. Such a structure! ? le! Any material that has already been installed can be used as a base material.

In the improvement method of the present invention, Cr, Fe, or
By implanting one or more elements selected from , Sn, Ti, Hf, C1Si, Ni, W, A, and N, and then performing heat treatment in a non-oxidizing atmosphere,
Improves surface properties such as corrosion resistance and abrasion resistance of base materials.

The elements to be ion-implanted here include Cr, Fe, Sn, and Ni, which are generally used as compositional components of Zircaloys, and Ti and H, which are homologous to Zr and have a solid solution with Zr.
f. C and N, which are nonmetallic elements and are generally effective as components of superhard materials, or Si and W, which are generally regarded as impurity components.

It should be noted that a variety of elements such as An and a variety of combinations thereof may be utilized. By appropriately selecting the types and combinations of these elements, the amount of ion implantation, etc., it is possible to create a zirconium alloy with surface characteristics optimal for each application.

The types and combinations of elements to be implanted, as well as the amount of ions to be implanted, are desirably selected appropriately depending on the type of base material used. For example, Table 1 in the Examples of JP-A No. 61279675 states as a comparative example that corrosion resistance can be improved even if N is implanted by ion implantation into the surface of a base material that has been subjected to oxide layer formation treatment. In such cases, the N injection can be carried out from the surface of the substrate which has not been treated to form an oxide layer, thereby improving corrosion resistance and surface hardness (wear resistance). The surface properties such as surface properties can also be sufficiently improved by implanting N.

In the present invention, Cr, Ti, N, etc. can be mentioned as particularly preferable among the various implanted elements.

The amount (concentration) of the above-mentioned elements to be implanted varies depending on the composition of the base material used, the type and combination of elements to be implanted, the use of the resulting zirconium alloy, etc., so it is not possible to set it uniformly. For example, 10'3~10''
About 1oz/cm2, preferably 106 to 10"1o
It is appropriate to set the range to about ns/cm2.

There are no particular limitations on the equipment and method used for the ion implantation, and for example, ion implantation equipment such as various ion accelerators such as Kotscroft accelerators such as Kotscroft-Walton accelerators, Humpgraph accelerators, and tandem accelerators may be used. The ion implantation can be performed using various ion implantation methods such as the well-known ion implantation method.

The amount of the above-described element (ion) in the column, the distribution of the implanted element in the depth direction of the base material, or the thickness of the concentrated layer of the element are determined by the energy of the implanted ions, the implantation time, etc., depending on the selection of the acceleration voltage of the ion accelerator, etc. You can adjust it accordingly.

The acceleration voltage (the energy of the implanted ions) and the implantation time may be selected appropriately in consideration of the above points, and are not particularly limited. Generally speaking, the energy of the implanted ions is usually It may be selected as appropriate from the range of several keV or more, preferably from several tens of keV to several M eV.

That is, an element selected from the above elements according to the purpose is ionized, the ion is accelerated to an appropriate energy in a sufficient vacuum, and is caused to collide with a predetermined surface of the base material, so that the ion is ionized near the surface of the base material. Inject and add to.

At that time, by implanting ions with acceleration energy in the range of several tens of keV to several hundred keV, the concentration of the implanted element is at a maximum depth of about 0.1 gm in the depth direction of the base material, for example. It is possible to form a concentrated layer of implanted elements having a Gaussian distribution or a distribution close to it. The maximum concentration depth can be changed as appropriate depending on the type of ions to be implanted, the accelerating voltage, and the like. Furthermore, the distribution of the implanted elements can be controlled by changing the accelerating voltage over time. For example, high accelerations on the order of MeV can increase the maximum concentration depth, typically by several gm.

Note that when two or more types of element ions are implanted, they may be irradiated and implanted at the same time, or they may be irradiated and implanted in stages (sequentially), or a combination thereof may be used.

The ions (elements) implanted in this way form compounds, compositions, or precipitates on the surface layer of the zirconium alloy base material, or cause the surface layer to become a solid solution, become amorphous, or undergo phase transformation. and modify the vicinity of the surface. For example, when Ti and/or Hf are used as elements to be implanted, since these elements are easily dissolved in Zr, a solid solution thereof is usually easily formed in the surface layer. The thermal neutron cross section of T1 and Hf is larger than that of Zr, or the absolute amount to be implanted is only a very small amount compared to the entire base material, so there is no substantial problem. The injected C is
Normally, compounds (carbides) and precipitates are likely to be formed with elements such as Zr in the surface layer. Further, the implanted N mainly forms nitride with Zr. Note that Cr, Fe, Sn, and Ni are elements that are commonly used as compositional components of the entire base material, or, in the case of the zirconium alloy of the present invention, they are present in the base material subjected to ion implantation. Regardless of whether it is present or not, it is concentrated on the surface layer.

In the improvement method of the present invention, after the predetermined elements are ionized as described above, the obtained base material (ion-implanted base material) is heat-treated in a non-oxidizing atmosphere.

This heat treatment in a non-oxidizing atmosphere may be performed immediately after ion implantation, or after an appropriate period of time.

Here, a non-oxidizing atmosphere refers to a vacuum with a sufficient degree of vacuum, an inert atmosphere such as an inert gas, or a reducing gas atmosphere that does not substantially cause any oxidation damage to the base material or its surface. It refers to the atmosphere. Therefore, the atmosphere may contain trace amounts of oxidizing gases such as oxygen and moisture.

Examples of the inert gas include Group 0 gases such as helium, argon, and neon, nitrogen gas, and the like.

The degree of vacuum is usually 10-2 Torr or less, preferably 10-'Torr or less.

The non-oxidizing atmosphere can be achieved as any of the various atmospheres mentioned above, but is usually preferably a non-oxidizing atmosphere under vacuum, and generally continues in a vacuum at the level of vacuum at which the ion implantation is performed. A method in which the heat treatment is performed is preferably employed.

The temperature of the heat treatment is usually 20 [1~l, ODD°C
The temperature may be selected from a range of temperatures, preferably from about 300 to 800°C.

By performing heat treatment under these conditions, modification of the structure of the surface layer of the base material such as precipitation in the ion implantation layer, thermal diffusion of implanted elements, disappearance and growth of irradiation defects is promoted, and as a result, corrosion resistance, wear resistance, etc. improvement or enhancement of surface properties.

As described above, by performing the heat treatment after ion-implanting the predetermined element into the zirconium alloy base material, the surface properties such as corrosion resistance and abrasion resistance of the base material used can be easily and effectively improved. Something comes up.

According to such ion implantation method and heat treatment, only the composition of the surface layer can be effectively adjusted without changing the bulk composition of the base material.

Therefore, it is possible to effectively improve the surface properties, especially corrosion resistance and abrasion resistance (surface hardness), without impairing the inherent bulk properties (e.g., mechanical strength, ductility, etc.) of the base material. It has the advantage that characteristics can be optimized independently. At that time, optimization of the desired surface properties is achieved by selecting the type and combination of implanted elements, ion implantation conditions, etc., as described above, and also by selecting the heat treatment conditions described later. This can be easily achieved by controlling the composition and structure of the surface layer by adjusting the thickness of the layer.

In particular, in the surface-modified zirconium alloy of the present invention, since there are a wide variety of implanted elements, depending on their selection and combination, the surface layer may contain, for example, compounds, solid solutions, compositions, or precipitates, as described above. It is possible to easily realize configurations with various compositions such as
Moreover, the heat treatment performed after ionization can control the composition distribution generated by ionization and the structure, such as the type and size of compounds and compositions such as intermetallic compounds, by modification or rearrangement. Another advantage is that it is extremely easy to optimize the bulk properties and surface properties depending on the situation.

Another advantage is that it is not necessary to use particularly expensive Nb as the element to be ion-implanted.

Furthermore, in the method of the present invention, there is no need to perform any particular oxide layer formation treatment before ion implantation, which can significantly reduce manufacturing costs.

Therefore, according to the method of the present invention, surface properties such as corrosion resistance and wear resistance can be advantageously improved, and this method can be used to manufacture a variety of high-performance zirconium alloys depending on the application. I can do something.

According to the method of the invention, conventional nuclear reactors (especially light water reactors)
The mechanical strength, ductility, etc. of various zirconium alloys that are used in the reactor core environment and are required to have high corrosion resistance such as Noschler corrosion resistance and -like corrosion resistance in water and steam under high temperature and high pressure. It is possible to further improve the bulk properties of the material without impairing them. At that time, the method of the present invention can be applied to raw materials that have not yet been processed into parts, and parts that have already been processed as predetermined raw material reactor materials (for example, fuel cladding tube materials for light water reactors, channel boxes, spacers, control rod guides, etc.). It can be easily applied to various reactor-related materials such as simple pipes, upper and lower end plugs, etc., or to any of those components already installed or incorporated in the raw material reactor.

Of course, the method of the present invention can also be applied to improving the surface properties such as corrosion resistance and wear resistance of various zirconium alloy base materials for uses and purposes other than those mentioned above.

The surface-modified zirconium alloy of the present invention can be produced by applying the above-described method of the present invention to the desired base material.

During this production, within the scope that does not impede the purpose of the present invention,
Processes other than the ion implantation and heat treatment in a non-oxidizing atmosphere may be added as appropriate.

As mentioned above, the surface-modified zirconium alloy produced by applying the method of the present invention has various advantages in terms of manufacturing, cost, and optimal design of bulk and surface properties. Mainly by the method of the present invention, its surface properties such as corrosion resistance and abrasion resistance are sufficiently improved.
In particular, Noschler corrosion resistance and -
Corrosion resistance such as corrosion resistance has been significantly improved.
It can be advantageously used in various fields of application of zirconium alloys, including the various raw material furnace materials mentioned above, particularly in fields of application of zirconium alloys that require surface performance such as high corrosion resistance and/or wear resistance.

[Examples] Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples. The present invention is not limited to these Examples, and the present invention will be described without departing from the spirit of the present invention. Various variations and applications are possible.

(Examples 1 to 22 and Comparative Examples 1 to 3) Zircaloy-4, which is a typical conventional zirconium alloy, was used as the base material, and 11 types were selected from the surface, namely Cr, Fe, Sn, N
After implanting Ti, TiHf, C, N, Si, w, and An by the ion column implantation method, each ion implantation material was subjected to heat treatment at 450 and 650°C in a vacuum of 10-'Torr. temperature of 30
After heating for 1 minute, a desired zirconium alloy with a total of 22 kinds of surface layer compositions adjusted and controlled was obtained.

The acceleration voltage (energy of implanted ions) in ion implantation was 160 keV in all cases, and the amount of implanted ions was 1xlO" for N (implanted as N').
1 ons/cs+2, and 3xlO17 ions/cm2 for other elements (implanted as negative cations).

The 22 types of zirconium alloys obtained above (the zirconium alloys of the present invention) and each of the ion-implanted zirconium alloys that were not subjected to the heat treatment as a comparative example were subjected to a corrosion test in an autoclave in pure water for 4 days.
00'C1105% pressure, 72 hours and 500°C1105
Testing was carried out under atmospheric pressure and for 24 hours, and corrosion resistance was evaluated based on the amount of increase in corrosion at that time.

The results are shown in Table 2.

As can be seen from the table, in most cases, heat-treated samples show better corrosion test results than their unheat-treated counterparts, depending on the type of implanted ions, heat treatment temperature, and corrosion test temperature. Corrosion increases or decreases,
The effect of heat treatment on improving corrosion resistance was observed.

Table (f%F = ci! Kano L74 Shimabatsukun 420.'1XWk
118-22 [mg/dm"1 [Effects of the Invention] According to the present invention, after a specific element is implanted into the surface or near the surface of a zirconium alloy base material by an ion implantation method, heat treatment is performed in a non-oxidizing atmosphere. By employing a specific method of oxidation, it is possible to easily and effectively control the composition and structure of the surface layer of the entire substrate or a desired portion of the substrate. Surface properties such as corrosion resistance and abrasion resistance of desired parts of unprocessed products such as materials and processed products such as parts, especially under neutron irradiation, which is the core environment of light water reactors, and in high-temperature and high-pressure water and steam. Production of a surface-modified zirconium alloy that can advantageously improve surface properties such as Noschler corrosion resistance and -like corrosion resistance without impairing bulk properties such as mechanical strength and ductility inherent in the base material. I can provide a method.

In addition, the surface-modified zirconium alloy produced by this method can be used, for example, in fuel cladding materials for light water reactors, channel boxes, spacers, control rod guide simple tubes, upper and lower end plugs, and various raw material reactor-related materials. Something comes up.

Claims (1)

[Claims] (1) C on the surface or near the surface of the zirconium alloy
r, Fe, Sn, Ni, Ti, Hf, C, N, Si, W
and one or more elements selected from Al,
A method for producing a surface-modified zirconium alloy, which comprises implanting the zirconium alloy by an ion implantation method, and heat-treating the zirconium alloy after the ion implantation in a non-oxidizing atmosphere.