JPH03183783A - Formation of titanium nitride type film - Google Patents

Abstract

PURPOSE:To directly, safely, and easily form a titanium nitride type film by applying, e.g., a solution of titanium alkoxide to the surface of a base material composed of ferrous metal containing specific amounts of carbon, drying the above base material, and then carrying out heating at a temp. in a specific region in an inert atmosphere composed essentially of nitrogen. CONSTITUTION:Any of a solution of titanium alkoxide, a hydrolytic solution containing a hydrolyzed substance of the titanium alkoxide, and a mixed solution containing at least either of the titanium alkoxide and hydrolyzed substance of the titanium alkoxide by 50mol.% and also containing a zirconium alkoxide is applied to the surface of a base material composed of a ferrous metal containing 0.04-4.2wt.% carbon, followed by drying. Subsequently, the above base material is heated at 850-1100 deg.C in an inert atmosphere composed essentially of nitrogen. By this method, the gold-colored titanium nitride type film having high hardness and excellent in corrosion resistance can be formed on the base material composed of the ferrous metal.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for safely and easily forming a titanium nitride group having high hardness, excellent corrosion resistance, and a golden color on an iron-based metal substrate.

The present invention is applicable to surface hardening treatment of tools etc., decoration of various parts,
Used for surface treatment of chemical containers that require corrosion resistance.

[Conventional technology]

As conventional methods for forming titanium nitride films, PVD methods such as ion blasting and sputtering, CVD methods, and the like are known.

On the other hand, after applying metal alkoxide solution or its hydrated waste,
Among the methods of forming a film on a glass or ceramic substrate by drying and heating (so-called sol-gel method), many methods for forming an oxide film are known. On the other hand, as a method for forming a titanium nitride film using this sol-gel method, a method is known in which a titanium oxide group is grown on a quartz glass substrate by the sol-gel method and then heated in ammonia (
"Molten Salt", Volume 31'! J2 issue, p. 158).

[RS that the invention is trying to solve! ! ]

The method of forming a titanium nitride film using the PVD method or the like has problems in that it is difficult to form the film over a large area, and special and expensive equipment is required.

On the other hand, in the latter method using the sol-gel method, it is possible to form a film over a large area, but the nitride film is only formed by heating in ammonia, which has a high reaction activity.
It is toxic, corrosive, flammable, etc., and is inconvenient to handle.

The present invention solves the above problems and forms a titanium nitride-based film (a film made only of titanium nitride) on an iron-based metal substrate by heating it in a nitrogen atmosphere using a titanium alkoxide solution or the like. As a result of various experiments, the present invention was completed by discovering through various experiments that it is possible to directly, safely and easily form a membrane containing the same. That is, forming a titanium nitride-based film directly on an iron-based metal substrate under a nitrogen atmosphere was completely unthinkable in the past.

Furthermore, the formation of a functional film made of titanium nitride and other metal oxides using the mixed solution is novel and unprecedented. As described above, an object of the present invention is to provide a method for safely and simply forming a titanium nitride film with good adhesiveness and excellent aesthetic appearance on an iron-based metal substrate without using an ammonia atmosphere.

[Means to solve the problem]

The method for forming a titanium nitride film of the present invention involves applying a titanium alkoxide solution or the like onto the surface of an iron-based metal substrate containing 0.04 to 4.2% by weight (hereinafter simply referred to as %) of carbon, and drying. , then 850-1 in an inert atmosphere such as nitrogen.
The method is characterized in that a titanium nitride film is formed by heating to 100°C.

As the alkoxide, ethoxide, propoxide or butoxide, and mixtures thereof, etc. are used,
Usually, it is used as an alkoxide solution by dissolving it in a hydrocarbon-based, alcohol-based, or amine-based solvent. The concentration is not particularly limited, but can be selected depending on the appropriate coating thickness, ease of application, etc. The hydrolyzed solution is usually prepared by dissolving the metal alkoxide in a water-soluble solvent such as alcohol or amine, and adding water and a small amount of hydrochloric acid. It can also be a complete one. In addition, a substance that stabilizes these solutions (for example, a chelating agent, etc.) or a substance that adjusts viscosity may be added to these alkoxide solutions or their hydrolysates.

The "mixed solution" contains 50 mol% or more of a titanium compound such as titanium alkoxide based on other metal components,
Others include zirconium alkoxide. This is because if this amount is less than 50 mol%, the performance, coloring, etc. as a titanium nitride film will not be sufficient. Here, zirconium alkoxide is used because it does not react with titanium and produce compounds.
Moreover, it does not become glass after heating. This usually includes the commonly used auxiliary metal alkoxides, such as IJ. This zirconium metal element may be added as a separately prepared zirconium alkoxide solution or sol, or may be added as a solution or sol of a composite alkoxide of titanium and zirconium. Note that metal elements such as alkali metals, alkaline earth metals, boron, and silicon cannot be used because they react with titanium.

As the ferrous metal substrate, common ferrous metals such as common steel, tool steel, cast iron, and stainless steel can be used. This base is 0
．． Contains 0.4-4.2% carbon.

If it is less than 0.04%, a titanium nitride film will not be formed sufficiently, and if it exceeds 4.2%, the crystals of the substrate will become large and the surface will become rough, which is not preferable.

The method of applying the alkoxide solution to the substrate is not particularly limited, and spin cord, spray, dipping methods, etc. can be used, but among these methods, the dipping method forms the most uniform and defect-free titanium nitride film. This is preferable because it allows

Further, drying is performed to evaporate the solvent and further promote hydrolysis of the metal alkoxide by moisture in the air. Note that if the solvent is insufficiently removed, carbon components will remain after heating, which is not preferable.

The drying method is not particularly limited, but can be easily carried out using a normal electric dryer or the like.

The heating atmosphere is an atmosphere mainly containing nitrogen.

This atmosphere may be an atmosphere consisting essentially only of nitrogen, or a mixed gas atmosphere mainly composed of nitrogen and consisting of about 50% by volume or more of nitrogen and an inert gas such as argon or helium.

The heating temperature is 850°C to 1100°C. In this temperature range, a titanium nitride-based film is fully reacted and formed; below 850°C, the reaction is not sufficient;
The reaction is almost complete by the time it reaches 110
This is because there is little significance even if the temperature exceeds 0° C., and the material of the substrate itself may be transferred, and it is uneconomical.

The device used for heating is usually a device that can cut off the inflow of air into the furnace and allow nitrogen gas to flow in for heating, but it is desirable to have a device that can replace the air in the furnace with nitrogen before heating. An ordinary atmosphere heating furnace, for example, an atmosphere furnace for metal heat treatment is used. The heating temperature and heating time within the predetermined range are variously selected depending on the type of iron-based metal, the thickness of the coating film, etc.

[Effect]

This formation method involves forming a dry coating film on the surface of a predetermined iron-based metal substrate using an alkoxide solution, etc., and heating it to a predetermined temperature in an inert atmosphere mainly composed of nitrogen to cause the alkoxide and nitrogen to react. A titanium nitride-based film is formed. Since this nitrogen is inert, it is normally difficult to imagine that it would react with titanium alkoxide at 850°C to 1100°C to produce nitrides, even if it is tried. However, in this method, after conducting various experiments, it was discovered that when a predetermined iron-based metal substrate is used, a titanium nitride-based film can be selectively formed.

The reason for this effect is still not clear, but as shown in the examples below, (1) a good film could not be formed when using a metal substrate such as glass, ceramic, or copper; (2)
Considering that steel with a carbon content of 0.48% forms an extremely good film, the crystal shape or surface morphology of the iron surface,
It is thought that the material itself, such as iron or iron carbide, exhibits a catalytic action to promote the reaction.

In any case, this method was able to carry out the reaction even when inert nitrogen was used as the nitrogen source without using highly active ammonia.

〔Example〕

The present invention will be specifically explained below using Examples.

The iron-based metal substrate used in this example was approximately 2 x 5 cm.
It is a plate shape with a thickness of 0.3 to 1 cttr, and its surface is polished with emery paper, wrapping, etc.
Puff polishing was performed using 5 μm alumina abrasive grains. In addition, for heating, an atmosphere electric furnace for metal heat treatment (furnace internal dimensions 8φ x 6
5C1l) was used. To confirm the formation of titanium nitride film,
This was done using X-ray diffraction method.

Example 1 1 mol of titanium impropoxide to 1 mol of cyclohexane
1 to prepare a solution. This solution was applied to ordinary steel (carbon content 0.48%) by a dipping method. Thereafter, it was dried at 120° C. for 30 minutes using an electric dryer to completely remove the solvent, and then nitrided using the electric furnace. First, the air in the furnace was evacuated to 0.2 Torr or less using a vacuum pump (rotary pump), and then nitrogen gas was introduced to replace the air with nitrogen. Then in/
The mixture was heated to 960° C. at a rate of about 00° C./hour at normal pressure while nitrogen was flowing at a flow rate of 100° C./hour, and maintained for 1 hour.

After cooling, the coated ordinary steel was taken out of the furnace and its surface was observed. A strongly adhered film with a golden metallic luster was formed, and force was applied with a piece of metal such as a wire until the material was scratched. Even when added, the film did not peel off. As a result of X-ray diffraction of the coating surface, as shown in Figure 1, diffraction lines based on not only the base material ordinary steel (main component α-Fe, marked with black circles) but also titanium nitride (marked with white circles) were observed. The formation of a titanium nitride film was confirmed.

Example 2 An experiment was conducted in the same manner as in Example 1 except that the heating temperature was 880° C. and the heating time was 5 hours, and the same results as in Example 1 were obtained.

Example 3 The same procedure as Example 1 was carried out except that ordinary steel with a carbon content of 0.25% was used. Although the golden metallic luster was a little thin, it showed a very good metallic luster. Similar results to Example 1 were obtained.

Example 4 The same procedure as in Example 1 was carried out except that tool steel with a carbon content of 1.0% was used and the heating temperature for nitriding was 1070°C, and the same results as in Example 1 were obtained. It was done.

Example 5 The same procedure as Example 4 was carried out except that ductile pig iron having a carbon content of 4.24% was used. As a result, the metallic luster was thin (slightly thinner than in Example 3) and the surface was somewhat rough, but diffraction lines of titanium nitride were observed in X-ray diffraction.

Example 6 The same procedure as in Example 4 was carried out except that SUS 304 stainless steel was used, and a slightly whitish golden film was obtained. According to the results of X-ray diffraction of this film, diffraction lines matching titanium carbide as well as titanium nitride were also observed.

Example 7 Titanium isopropoxide was used as 2 moles, the heating temperature was set to 1070°C, and coating, drying, and heating were carried out for 2 times under the same conditions.
The same procedure as in Example 1 was carried out except that the cycle was repeated. Incidentally, according to scanning electron microscope observation of a cross section of this coating film, the thickness of the coating film was as thick as 1 to 1.5 μm.

Even when the coating film was thickened by increasing the number of coatings in this manner, defects such as color unevenness, cracking, and peeling did not occur, and a coating film with a deeper golden color was obtained. The adhesion of this coating film was also good, and the film did not peel off even when force was applied to the material with a piece of metal such as a wire.

Example 8 Titanium isopropoxide was dissolved in an equal volume mixture of jetanolamine and isopropyl alcohol, and the concentration was 0.
．． A 5 mol/1 solution was used, and drying was performed at 150°C.
The same procedure as in Example 1 was carried out except that the test was carried out for 0 minutes, and the same results as in Example 1 were obtained.

Example 9 0.1 mol of titanium isopropoxide was dissolved in 0.4 mol of ethyl alcohol, and a trace amount of hydrochloric acid and 0.04 mol of titanium isopropoxide were dissolved in this solution.
．． Example 1 was carried out in the same manner as in Example 1, except that a partial hydrolyzate prepared by adding and hydrolyzing a solution consisting of 1 mol of water and 0.4 mol of ethyl alcohol was used. As a result, the metallic luster was slightly thinner than in Example 1, but
In X-ray diffraction, diffraction lines of titanium nitride were observed.

Example 10 The same procedure as Example 1 was carried out except that a cold rolled steel plate with a carbon content of 0.040% was used. The metallic luster was slightly thinner, but otherwise the same results as in Example 1 were obtained. It was done.

Example 11 A solution in which titanium isopropoxide was dissolved in cyclohexane 11 at a ratio of 1.3 mol, and zirconium normal propoxide and yttrium isopropoxide were dissolved in cyclohexane 11 at a ratio of 0.96 mol and 0.96 mol, respectively.
Each was prepared with a solution in which they were dissolved at a ratio of 0.8 mol.

A mixture of equal amounts of these solutions (mixed solution) was prepared, this was used as a dip coating liquid, and the heating temperature was 1070°C.
The procedure was carried out in the same manner as in Example 1 except that a bluish-gold film was obtained.

In addition, when X-ray diffraction was performed, diffraction lines matching titanium nitride,
Diffraction lines considered to be low-grade titanium oxide and diffraction lines consistent with tetragonal zirconia were observed, confirming the formation of a titanium nitride-based film containing zirconia.

Comparative Example 1 The same procedure as in Example 1 was carried out except that a steel plate for enameling with a carbon content of 0.005% was used, but no substantial titanium nitride film was observed.

Comparative Example 2 Using glass such as quartz glass or ceramics such as alumina as the substrate, temperature was increased from 850°C under the same atmosphere as in Example 1.
Even when heated at a temperature of 1100° C., substantial formation of a titanium nitride film was not observed. Similarly, no titanium nitride film was observed even when nickel or molybdenum was used as the metal substrate and heated to 1100°C, and even when copper was used and heated to 1050°C.

The effects of the examples show that when various steels with carbon contents of 0.04 to 4.2% are heated at temperatures of 880°C to 1070°C, all of them produce good titanium nitride films (including titanium nitride films). ) was formed. Particularly good results were shown for common steel with a carbon content of 0.48% (Example 1.2) and tool steel with a carbon content of 1.0% (Example 4). Among these, the former reacted sufficiently with inert nitrogen even at a low temperature of 880° C. to form a good film. In addition, when the film is thickened by applying it three times (Example 7), it shows a deep color, so even when the above-mentioned slightly lighter color is applied (Example 3.9), sufficient coloring and film can be obtained by this method. can.

When using a partial hydrolyzate using hydrochloric acid (Example 9),
Since it is easy to prepare a transparent solution, it is easy to create a transparent coating film and convenient to handle, and because it is a polymer, it is easy to create a film.

Furthermore, in the composite ceramic film in which titanium nitride and metal oxide coexisted (Example 11), a film with excellent stability and strength was formed, and compared to the case of a simple titanium nitride film (Example 1, etc.). As a result, it was possible to exhibit better fracture toughness and a different color (same as in Example 6).

It should be noted that the present invention is not limited to those shown in the above-mentioned specific embodiments, and may be modified in various ways within the scope of the present invention depending on the purpose and use.

〔Effect of the invention〕

Titanium nitride film has high hardness, excellent corrosion resistance, and is golden in color and has an excellent aesthetic appearance. According to this method, such a useful film can be formed on an iron-based metal substrate. , it is possible to produce coated products with excellent corrosion resistance and aesthetic appearance. In addition, the metal base is iron-based and is inexpensive and common, so it has an extremely wide range of applications, is economical, and is very useful. Furthermore, since this method uses a predetermined metal substrate, it can be carried out at low temperature heating, and a film with excellent adhesion and a beautiful finished surface can be formed. Further, according to this method, unlike an ammonia atmosphere, a titanium nitride film can be formed in a nitrogen atmosphere or the like, so there is no concern about toxicity, corrosivity, or combustibility, and the method can be carried out extremely safely and inexpensively. Further, since this method uses a sol-gel method, special and expensive equipment such as PVD method is not required. Therefore, it is easy to handle,
Manufacturing costs can be reduced, and a coating can be formed uniformly and reliably even when using a large or complicated substrate.

Furthermore, by using a mixed solution containing zirconium alkoxide, it is possible to form a titanium nitride film made of composite ceramic in the same way, so it is possible to easily impart properties not found in a simple titanium nitride film, and furthermore, it is possible to form a titanium nitride film made of a composite ceramic. It is also possible to give different shades of gold.

As described above, by selecting various film-forming conditions, a film can be formed depending on the purpose and use, and its range of use is extremely wide.

[Brief explanation of drawings]

The figure is a graph showing the X-ray diffraction results of the coating surface in Example 1.

Claims (1)

[Claims] (1) Titanium alkoxide solution (I), hydrolyzate containing titanium alkoxide hydrolyzate (II)
Or, the mixed solution (III) containing at least 50 mol% of titanium alkoxide and a hydrolyzate of titanium alkoxide and zirconium alkoxide is mixed into an iron-based solution containing 0.04 to 4.2% by weight of carbon. 1. A method for forming a titanium nitride film, which comprises coating the surface of a metal substrate, drying it, and then heating it to 850 to 1100°C in an inert atmosphere mainly containing nitrogen.