阅读说明：本技术 用于显示钴铬钼合金金相组织的腐蚀剂和腐蚀方法 (Corrosive and corrosion method for displaying metallographic structure of cobalt-chromium-molybdenum alloy ) 是由 毛桂江 毛咏发 张允继 李文涛 于 2020-04-26 设计创作，主要内容包括：本发明公开一种用于显示钴铬钼合金金相组织的腐蚀剂和腐蚀方法。其中,所述用于显示钴铬钼合金金相组织的腐蚀剂含有强碱、氧化剂及水。本发明的技术方案能够有效降低腐蚀时间,提升腐蚀效果,使得金相晶界清晰显示。(The invention discloses a corrosive agent and a corrosion method for displaying a cobalt-chromium-molybdenum alloy metallographic structure. The corrosive for displaying the metallographic structure of the cobalt-chromium-molybdenum alloy contains strong base, an oxidant and water. According to the technical scheme, the corrosion time can be effectively shortened, the corrosion effect is improved, and the metallographic crystal boundary can be clearly displayed.)

1. The corrosive agent for displaying the metallographic structure of the cobalt-chromium-molybdenum alloy is characterized by comprising strong base, an oxidant and water.

2. The etchant for displaying the metallographic structure of a cobalt-chromium-molybdenum alloy according to claim 1, wherein the etchant contains, in parts by mass: 1-8 parts of strong base; 1-8 parts of an oxidant; and 25-200 parts of water.

3. The corrosive agent for displaying the metallographic structure of a cobalt-chromium-molybdenum alloy according to claim 1, wherein said strong base is sodium hydroxide or potassium hydroxide; and/or the presence of a gas in the gas,

the oxidant is potassium permanganate or hydrogen peroxide.

4. The corrosive agent for displaying the metallographic structure of a cobalt-chromium-molybdenum alloy according to any one of claims 1 to 3, wherein the corrosive agent further contains a surfactant.

5. The corrosive agent for displaying the metallographic structure of a cobalt-chromium-molybdenum alloy according to claim 4, wherein the content of said surfactant is 1 to 5 parts by mass; and/or the presence of a gas in the gas,

the surfactant is at least one of sodium dodecyl benzene sulfonate, stearic acid, fatty glyceride and Tween.

6. The etchant for displaying the metallographic structure of a cobalt-chromium-molybdenum alloy according to any one of claims 1 to 3, wherein the etchant further contains a corrosion inhibitor.

7. The corrosive agent for displaying the metallographic structure of a cobalt-chromium-molybdenum alloy according to claim 6, wherein the content of said corrosion inhibitor is 1 to 5 parts by mass; and/or the presence of a gas in the gas,

the corrosion inhibitor is at least one of chromate, nitrite, benzotriazole and hexadecylamine.

8. The corrosive agent for displaying the metallographic structure of the cobalt-chromium-molybdenum alloy as claimed in any one of claims 1 to 3, wherein the weight percentages of the components in the cobalt-chromium-molybdenum alloy are as follows: co: 40% -75%, Cr: 15% -35%, Mo: 2 to 10 percent.

9. An etching method for displaying a metallographic structure of a cobalt-chromium-molybdenum alloy, characterized in that the etching method comprises the following steps:

grinding the surface to be corroded of the cut metallographic specimen, wherein the metallographic specimen is cobalt-chromium-molybdenum alloy;

polishing and cleaning the surface to be corroded after grinding;

carrying out corrosion treatment on the cleaned surface to be corroded by using the corrosive agent as defined in any one of claims 1 to 8;

and cleaning and drying the corroded metallographic specimen.

10. The corrosion method for displaying a metallographic structure of a cobalt-chromium-molybdenum alloy according to claim 9, wherein the step of grinding the surface to be corroded of the cut metallographic specimen comprises the steps of:

putting the cut metallographic specimen into a polishing machine, and sequentially grinding the surface to be corroded by using water sand paper with different particle sizes; and/or the presence of a gas in the gas,

the steps of polishing and cleaning the surface to be corroded after grinding treatment comprise:

polishing the surface to be corroded after grinding by using a polishing machine for 2-10 min, and washing the surface to be corroded by sequentially using water and alcohol; and/or the presence of a gas in the gas,

the step of carrying out corrosion treatment on the cleaned surface to be corroded by adopting a corrosive agent comprises the following steps:

and dropwise adding a corrosive agent on the cleaned surface to be corroded for corrosion, wherein the corrosion time is 20s-90 s.

Technical Field

The invention relates to the technical field of metallographic corrosion, in particular to a corrosive agent and a corrosion method for displaying a cobalt-chromium-molybdenum alloy metallographic structure.

Background

The cobalt-chromium-molybdenum alloy is one of cobalt-based alloys, and can be used as an appearance piece of a wearable electronic product due to excellent corrosion resistance and wear resistance, so that the service life and the appearance reliability of the electronic product are improved. Meanwhile, the material has the characteristics of good fatigue resistance, high tensile strength, good processability and the like, and is widely applied to production and manufacture of biomedical materials (such as human skeleton and organ materials of dentistry, bone joints and the like).

Because cobalt-chromium-molybdenum alloy has excellent corrosion resistance, the metallographic structure of the cobalt-chromium-molybdenum alloy cannot be shown by adopting a common chemical corrosive, in the related technology, the metallographic structure of the cobalt-chromium-molybdenum alloy is usually corroded by adopting acid (such as aqua regia or hydrofluoric acid) with strong corrosivity, but the corrosion time is long, the corrosion effect is poor, and the metallographic grain boundary cannot be clearly displayed.

The above is only for the purpose of assisting understanding of the technical aspects of the present invention, and does not represent an admission that the above is prior art.

Disclosure of Invention

The invention mainly aims to provide a corrosive agent and a corrosion method for displaying a cobalt-chromium-molybdenum alloy metallographic structure, aiming at effectively reducing corrosion time, improving corrosion effect and enabling a metallographic grain boundary to be displayed clearly.

In order to achieve the purpose, the corrosive agent for displaying the metallographic structure of the cobalt-chromium-molybdenum alloy comprises strong base, an oxidant and water.

Optionally, the corrosive agent contains, by mass: 1-8 parts of strong base; 1-8 parts of an oxidant; and 25-200 parts of water.

Optionally, the strong base is sodium hydroxide or potassium hydroxide; and/or the oxidant is potassium permanganate or hydrogen peroxide.

Optionally, the caustic also contains a surfactant.

Optionally, the content of the surfactant is 1-5 parts by mass; and/or the surfactant is at least one of sodium dodecyl benzene sulfonate, stearic acid, fatty glyceride and Tween.

Optionally, the corrosive agent further contains a corrosion inhibitor.

Optionally, the content of the corrosion inhibitor is 1-5 parts by mass; and/or the corrosion inhibitor is at least one of chromate, nitrite, benzotriazole and hexadecylamine.

Optionally, the cobalt-chromium-molybdenum alloy comprises the following components in percentage by weight: co: 40% -75%, Cr: 15% -35%, Mo: 2 to 10 percent.

The invention also provides a corrosion method for displaying the metallographic structure of the cobalt-chromium-molybdenum alloy, which comprises the following steps of:

grinding the surface to be corroded of the cut metallographic specimen, wherein the metallographic specimen is cobalt-chromium-molybdenum alloy;

polishing and cleaning the surface to be corroded after grinding;

carrying out corrosion treatment on the cleaned surface to be corroded by adopting the corrosive agent;

and cleaning and drying the corroded metallographic specimen.

Optionally, the step of grinding the surface to be corroded of the cut metallographic specimen includes:

putting the cut metallographic specimen into a polishing machine, and sequentially grinding the surface to be corroded by using water sand paper with different particle sizes; and/or the presence of a gas in the gas,

the steps of polishing and cleaning the surface to be corroded after grinding treatment comprise:

polishing the surface to be corroded after grinding by using a polishing machine for 2-10 min, and washing the surface to be corroded by sequentially using water and alcohol; and/or the presence of a gas in the gas,

the step of carrying out corrosion treatment on the cleaned surface to be corroded by adopting a corrosive agent comprises the following steps:

and dropwise adding a corrosive agent on the cleaned surface to be corroded for corrosion, wherein the corrosion time is 20s-90 s.

According to the technical scheme, the corrosive used for displaying the metallographic structure of the cobalt-chromium-molybdenum alloy contains strong base, oxidant and water, the strong base can effectively corrode the metallographic structure of the cobalt-chromium-molybdenum alloy, and the oxidant can perform redox reaction with the metallographic structure of the cobalt-chromium-molybdenum alloy, so that the metallographic grain boundary can be displayed clearly. Therefore, when the corrosive disclosed by the invention is used for corroding the metallographic structure of the cobalt-chromium-molybdenum alloy, the corrosion time can be effectively shortened, the corrosion effect is effectively improved, and the metallographic grain boundary can be clearly displayed. In addition, the corrosive agent is easy and safe to prepare, and is not easy to cause harm to the personal safety and health of operators.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.

FIG. 1 is a microscopic view of the metallographic grain boundary after the corrosion method for showing the metallographic structure of a cobalt-chromium-molybdenum alloy according to the present invention.

The implementation, functional features and advantages of the objects of the present invention will be further explained with reference to the accompanying drawings.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present invention.

The invention provides a corrosive agent for displaying the metallographic structure of a cobalt-chromium-molybdenum alloy, wherein the cobalt-chromium-molybdenum alloy is generally in a casting state or a powder metallurgy sintering state, and can be a cobalt-chromium-molybdenum alloy in other forms, and the corrosive agent is within the protection scope of the invention.

The cobalt-chromium-molybdenum alloy has excellent corrosion resistance as a cobalt-based alloy, in the related technology, the metallographic structure of the cobalt-chromium-molybdenum alloy is usually corroded by acid (such as aqua regia or hydrofluoric acid) with strong corrosivity, but the corrosion time is long and the corrosion effect is poor.

The corrosive for displaying the metallographic structure of the cobalt-chromium-molybdenum alloy contains strong base, an oxidant and water. The strong base may be an alkali metal hydroxide, such as sodium hydroxide or potassium hydroxide, or an alkaline earth metal hydroxide, such as calcium hydroxide or barium hydroxide, or other strong organic bases, and is within the scope of the present invention. The corrosive agent is a solution, water is used as a solvent, strong alkali has strong corrosivity and can effectively corrode a cobalt-chromium-molybdenum alloy metallographic structure, and the oxidant has good oxidability and can perform an oxidation-reduction reaction with the cobalt-chromium-molybdenum alloy metallographic structure, so that a metallographic grain boundary is clearly displayed. In addition, when the corrosive disclosed by the invention is used for carrying out corrosion operation on the cobalt-chromium-molybdenum alloy metallographic structure, the operation is simpler, the corrosion time is shorter, the corrosion operation is safer, and the harm to the personal safety and health of operators is not easy to cause.

It should be noted that when the corrosive disclosed by the invention is used for metallographic corrosion of a cobalt-chromium-molybdenum alloy metallographic structure, a more obvious and clear crystal boundary can be obtained within 20 seconds at least, and the corrosion is more rapid and effective.

Therefore, it can be understood that, according to the technical scheme of the invention, the corrosive agent for displaying the metallographic structure of the cobalt-chromium-molybdenum alloy contains strong base, oxidant and water, the strong base can effectively corrode the metallographic structure of the cobalt-chromium-molybdenum alloy, and the oxidant can perform redox reaction with the metallographic structure of the cobalt-chromium-molybdenum alloy, so that the metallographic grain boundary can be displayed clearly. Therefore, when the corrosive disclosed by the invention is used for corroding the metallographic structure of the cobalt-chromium-molybdenum alloy, the corrosion time can be effectively shortened, the corrosion effect is effectively improved, and the metallographic grain boundary can be clearly displayed. In addition, the corrosive agent is easy and safe to prepare, and is not easy to cause harm to the personal safety and health of operators.

In order to make the corrosion effect of the corrosive agent faster and more effective, the content of each component is usually properly adjusted when the corrosive agent is prepared. Generally, the etchant contains, by mass: 1-8 parts of strong base; 1-8 parts of an oxidant; and 25-200 parts of water. For example, in the etchant formulation, the strong base is used in an amount of 1 part, 3 parts, 5 parts, 7 parts, or 8 parts, the oxidizer is used in an amount of 1 part, 3 parts, 5 parts, 7 parts, or 8 parts, and the water is used in an amount of 25 parts, 50 parts, 100 parts, 150 parts, or 200 parts.

Alternatively, the strong base is sodium hydroxide or potassium hydroxide. The strong alkali is selected from sodium hydroxide or potassium hydroxide, has strong corrosivity and can effectively corrode the cobalt-chromium-molybdenum alloy metallographic structure. In addition, the sodium hydroxide and the potassium hydroxide are low in price and easy to obtain.

Optionally, the oxidant is potassium permanganate or hydrogen peroxide. The oxidant is selected from potassium permanganate or hydrogen peroxide, has strong oxidizability, and can perform redox reaction with a cobalt-chromium-molybdenum alloy metallographic structure, so that a metallographic grain boundary can be clearly displayed. In addition, the potassium permanganate and the hydrogen peroxide are low in price and easy to obtain.

As can be understood, the corrosive agent has the advantages of low price of each component in the formula, easy obtaining, easy preparation, safe preparation and low cost.

Further, the etchant also contains a surfactant. The addition of the surfactant can improve the activity of the corrosive, so that dirt easily adhered to the surface of the metallographic specimen is quickly dissolved, the quality of metallographic preparation is improved, and the observation of a grain boundary in a metallographic structure is facilitated. Meanwhile, the surfactant can also reduce the surface tension of the surface of the metallographic sample, so that the corrosive agent is quickly contacted with the surface to be corroded of the metallographic sample, and the corrosion time is favorably shortened.

It should be noted that the surfactant may be selected from an anionic surfactant, a cationic surfactant or a nonionic surfactant, and all of them are within the scope of the present invention.

The surfactant is added in an appropriate amount to ensure that the surfactant fully exerts its effect. Generally, the surfactant is present in an amount of 1 to 5 parts by mass, such as 1 part, 2 parts, 3 parts, 4 parts, or 5 parts.

Optionally, the surfactant is at least one of sodium dodecyl benzene sulfonate, stearic acid, fatty glyceride and Tween. When a surfactant is selected, one or more of them may be selected as a mixture.

Further, the etchant also contains a corrosion inhibitor. The corrosion inhibitor is also called as a corrosion inhibitor, and after the corrosion inhibitor is added, a protective film is formed on the surface to be corroded of the metallographic specimen to slow down the corrosion operation speed, so that the corrosion operation is carried out more stably, the quality of metallographic phase manufacturing can be improved, and the observation of a grain boundary in a metallographic structure is facilitated.

It should be noted that the corrosion inhibitor may be selected from inorganic corrosion inhibitor, organic corrosion inhibitor or polymer corrosion inhibitor, which is not limited herein and is within the protection scope of the present invention.

In order to ensure that the corrosion inhibitor fully exerts its effect, the addition amount of the corrosion inhibitor is proper. Optionally, the corrosion inhibitor is present in an amount of 1-5 parts by mass, for example 1 part, 2 parts, 3 parts, 4 parts or 5 parts.

Optionally, the corrosion inhibitor is at least one of chromate, nitrite, benzotriazole, hexadecylamine. When the corrosion inhibitor is selected, one or more of the mixtures can be selected.

Furthermore, the corrosive agent also contains organic alcohols, such as ethanol or propanol, after the organic alcohols are added, the diffusion and convection velocity can be effectively controlled, and the surface to be corroded of the metallographic sample is corroded uniformly, so that the definition of a grain boundary in a metallographic structure can be improved, and the observation is convenient.

The cobalt-chromium-molybdenum alloy is mainly a cast or powder metallurgy sintered cobalt-chromium-molybdenum alloy, and comprises the following components in percentage by weight: co: 40% -75%, Cr: 15% -35%, Mo: 2 to 10 percent. Of course, the cobalt-chromium-molybdenum alloy also contains some trace metal impurities, and the weight percentage content of the trace metal impurities is not higher than 1%. When the corrosive is used for corroding the metallographic structure of the cobalt-chromium-molybdenum alloy, the cobalt-chromium-molybdenum alloy can be quickly and effectively corroded, and a relatively obvious and clear crystal boundary can be easily obtained.

The invention also provides a corrosion method for displaying the metallographic structure of the cobalt-chromium-molybdenum alloy, which comprises the following steps:

grinding the surface to be corroded of the cut metallographic specimen, wherein the metallographic specimen is cobalt-chromium-molybdenum alloy;

polishing and cleaning the surface to be corroded after grinding;

carrying out corrosion treatment on the cleaned surface to be corroded by adopting the corrosive agent;

and cleaning and drying the corroded metallographic specimen.

Specifically, the metallographic specimen is a cobalt-chromium-molybdenum alloy in a casting state or a powder metallurgy sintering state, firstly, a cobalt-chromium-molybdenum alloy material is subjected to linear cutting, and generally cut into a metallographic specimen with the size of 25mm × 25mm × 6mm, because the metallographic specimen has a small size, the metallographic specimen is generally required to be inlaid for facilitating subsequent treatment.

Optionally, the step of grinding the surface to be corroded of the cut metallographic specimen includes:

and (3) putting the cut metallographic specimen into a polishing machine, and sequentially grinding the surface to be corroded by using water sand paper with different particle sizes.

Specifically, the grain size of the waterproof abrasive paper can be 400 meshes, 800 meshes, 1000 meshes, 1200 meshes, 1500 meshes and 2000 meshes, when grinding is carried out, the cut metallographic specimen is placed in a metallographic grinding and polishing machine, when the waterproof abrasive paper with the same mesh number is firstly adopted for grinding, and when the surface of the specimen is not scratched, the specimen is rotated by 90 degrees, so that the next grinding direction is perpendicular to the previous grinding direction until new grinding marks are uniform and consistent. Firstly, coarse grinding is carried out, then, finer waterproof abrasive paper is used for grinding in sequence, when the next thinner waterproof abrasive paper is used for grinding, the surface of a test sample is cleaned by clean water, and the test sample is rotated by 90 degrees, so that new and old grinding marks are vertical until the grinding is finished by adopting the waterproof abrasive paper with the size of 2000 meshes.

Optionally, the step of polishing and cleaning the surface to be etched after the grinding treatment includes:

and polishing the surface to be corroded after grinding by using a polishing machine for 2-10 min, and washing the surface to be corroded by sequentially using water and alcohol.

Specifically, the sample after grinding treatment is placed on a polishing machine, polishing is carried out on the sample by using 2-5 micron diamond grinding paste by replacing polishing cloth, the polishing time is 2-10 min, the surface of the sample is observed to be bright without any scratch, then the surface of the sample is washed by water, and then the surface of the sample is washed by alcohol.

Optionally, the step of performing etching treatment on the cleaned surface to be etched by using an etchant includes:

and dropwise adding a corrosive agent on the cleaned surface to be corroded for corrosion, wherein the corrosion time is 20s-90 s.

Specifically, a certain amount of corrosive agent is extracted by a dropper, the corrosive agent is dripped on a polished and cleaned metal polished surface for etching, the etching operation is carried out at normal temperature, and the etching time is 20s-90 s. And after corrosion, cleaning the steel plate by using alcohol, scrubbing the steel plate, drying the steel plate, and observing the grain boundary of the crystal grain by using a metallographic microscope.

It should be noted that, here, it is also possible to use tweezers to pick up cotton and dip the corrosive agent, and drop the corrosive agent on the surface to be corroded to corrode.

The corrosive and the corrosion method for displaying the metallographic structure of a cobalt-chromium-molybdenum alloy according to the present invention will be described in detail below with reference to specific examples.