JP4984562B2 - TiN film forming method and TiN continuous film forming apparatus on metal strip surface - Google Patents

Description

  The present invention relates to a TiN film forming method on a metal strip surface and a TiN continuous film forming apparatus in a continuous line using a CVD (chemical vapor deposition) method. It is intended to improve efficiency.

Titanium nitride (TiN), which has high hardness and excellent wear resistance, has been widely used as a surface coating material for improving the life of tool steel such as press dies and blades. Since this TiN is a nitride ceramic with a very high melting point, it is usually coated on the tool steel surface using vapor phase synthesis such as physical vapor deposition (PVD) or chemical vapor deposition (CVD). Is done.
In these methods, TiN is coated on the surface of the tool steel by generally setting the tool steel in a reactor maintained at a high temperature or in a vacuum state and supplying a raw material gas such as titanium tetrachloride or nitrogen for a certain period of time. The

Furthermore, in recent years, attempts have been made to coat the surface of the metal strip with TiN in a continuous line.
For example, according to Patent Document 1, when DLC (diamond-like carbon) is coated as an insulating coating to improve the magnetic properties of a grain-oriented electrical steel sheet, an example of coating TiN on the steel sheet surface as a pretreatment for improving adhesion is disclosed. It is disclosed.

  In addition, in a reaction zone maintained at a high temperature in a continuous line, when TiN is coated on a grain-oriented electrical steel sheet and cooled to room temperature, the magnetic properties are improved by utilizing the tension generated in the steel sheet due to the thermal contraction difference with the TiN film. For example, Patent Document 2 discloses a method of coating TiN by supplying a raw material gas (titanium tetrachloride) from a gas nozzle in a CVD continuous line, and Patent Document 3 discloses a gas supplied by a nozzle. And a method of coating a TiN film with good adhesion at a relatively high speed by optimizing the concentration of the source gas (titanium tetrachloride) in the gas supplied to the atmosphere.

Special table 2005-500435 gazette JP 2005-256075 A JP 2005-264213 A

  A method of synthesizing a ceramic film by a PVD method or a CVD method is widely used in the field of tool steel and semiconductor. However, these methods are a method in which a small sample is placed in a sealed reaction vessel, treated for a certain period of time, and then taken out. A method for synthesizing a ceramic coating on the surface of a metal strip of several thousand meters in a short time. As inappropriate.

  For example, Patent Document 1 illustrates an apparatus for performing DLC and TiN coating on a continuous line. However, although the PVD method is a film forming method that requires a high vacuum, no specific measures for applying to a continuous line in this respect are shown, and the CVD method is not described. No specific gas conditions and gas supply method are disclosed.

  In this regard, Patent Documents 2 and 3 describe specific methods for applying the TiN method to continuous lines. However, even if TiN is coated on the surface of the metal strip with the apparatus configured as described above, the proportion of Ti consumed for coating is at most about 10% of the supplied source gas (titanium tetrachloride), and the remaining Ti Adheres to a place other than the surface of the metal strip or is discharged from the reaction zone without forming TiN by combining with nitrogen.

As described above, the utilization efficiency of the raw material gas is extremely low, resulting in an increase in manufacturing cost. In addition, the discharged unreacted gas is neutralized with the alkali solution of the exhaust gas treatment facility. However, since most of the supplied gas is discharged without being reacted, a large burden is imposed on the exhaust gas treatment. Further, the unreacted gas is cooled and condensed in the piping from the reaction zone to the exhaust gas treatment facility, which may cause trouble in the exhaust system. When such a trouble occurs, the continuous film formation of TiN must be interrupted, and the production efficiency is significantly reduced.
Therefore, improving the utilization efficiency of the raw material gas is indispensable for industrially coating the TiN film on the metal strip surface in a continuous line.

  The present invention was developed as a result of intensive studies on various gas supply methods in order to meet the above-mentioned demands. When coating a TiN film on the surface of a metal strip, the utilization efficiency of the raw material gas is improved as compared with the conventional case. It is an object of the present invention to propose a TiN film forming method on the surface of a metal strip that has been improved significantly.

That is, the gist configuration of the present invention is as follows.
(1) In a continuous treatment line of a metal strip, when a reactive gas containing titanium chloride is supplied into a reaction furnace to continuously form a TiN film on the surface of the metal strip, A plurality of gas nozzles are arranged along the traveling direction of the metal strip, and among these gas nozzles, a gas containing titanium chloride is sprayed on the surface of the metal strip from the previous stage to generate TiN at the spraying position. while wherein the blowing gas containing no titanium chloride on the surface of the metallic strip from a subsequent stage, TiN film formation method of the metal strip surface.

(2) In the continuous treatment line of the metal strip, when a reactive gas containing titanium chloride is supplied into the reaction furnace to continuously form a TiN film on the surface of the metal strip, A plurality of gas nozzles are arranged along the traveling direction of the metal strip, and among these gas nozzles, one gas nozzle for spraying a gas containing titanium chloride and a subsequent gas not containing titanium chloride are blown 1 One or a plurality of gas nozzles are set as one set, and a plurality of sets are installed along the traveling direction of the metal strip, and the gas containing titanium chloride is sprayed on the surface of the metal strip, and TiN is applied to the spraying position. Characterized in that a metal that does not contain titanium chloride is blown onto the surface of the metal strip. TiN film forming method on strip surface.

(3) The above-mentioned (1), wherein the gas not containing titanium chloride is one or more selected from nitrogen gas, hydrogen gas, and other gases that do not interfere with the TiN film forming reaction. Or the TiN film-forming method of (2) description.

(4) The TiN film forming method as described in any one of (1) to (3) above, wherein a spray speed of the gas not containing titanium chloride is 0.5 to 50 m / s.

(5) A TiN continuous film forming apparatus for continuously forming a TiN film on the surface of a metal strip by supplying a reactive gas containing titanium chloride into a reaction furnace in a continuous processing line of the metal strip. In the reactor, a plurality of gas nozzles are arranged along the traveling direction of the metal strip. Among these gas nozzles, a gas containing titanium chloride is sprayed on the surface of the metal strip in the first stage. An apparatus for continuously forming TiN on the surface of a metal strip, characterized in that a gas nozzle for generating TiN is formed at the spraying position, and a gas nozzle for spraying a gas not containing titanium chloride on the surface of the metal strip is used in the subsequent stage.

(6) A TiN continuous film forming apparatus for continuously forming a TiN film on the surface of a metal strip by supplying a reactive gas containing titanium chloride into a reaction furnace in a continuous processing line of the metal strip. In the reactor, a plurality of gas nozzles are arranged along the traveling direction of the metal strip, and a gas containing titanium chloride is sprayed on the surface of the metal strip among the plurality of gas nozzles. One gas nozzle for generating TiN at the spray position and one or more gas nozzles for spraying a gas not containing titanium chloride on the surface of the metal strip are set as one set, and this set is set along the traveling direction of the metal strip. A TiN continuous film forming apparatus on a metal strip surface, wherein a plurality of sets are installed.

According to the present invention, when TiN is deposited, the utilization efficiency of titanium tetrachloride (TiCl ₄ ), which has been limited to a few percent, has been remarkably improved, and the deposition rate has been improved. It can also be increased. As a result, the TiN film formation cost in the continuous line can be remarkably reduced, and the load of exhaust gas treatment is reduced, so that the manufacturing stability is greatly improved.

Hereinafter, the present invention will be specifically described with reference to an example in which titanium tetrachloride is used as the titanium chloride of the source gas.
When synthesizing a TiN film by CVD using titanium tetrachloride, hydrogen, and nitrogen, a relatively high deposition rate can be obtained in the immediate vicinity of the source gas supply port, but the deposition rate decreases as the distance from the source gas supply port increases. . This is because, as described in the literature “ITO et al., Metal Surface Technology 54 (1984) vol.135, No.12”, HCl generated along with the generation of TiN has an action of inhibiting TiN film formation. Conceivable.

Usually, when a TiN film is coated on a material to be treated, the material to be treated is set at a position away from the gas supply port in order to avoid abrupt film formation that occurs in the vicinity of the source gas supply port. In this case, although the uniformity of the film is excellent, the film forming speed is as low as about 0.1 μm / min at the most, so that a long time is required for the processing. In addition, the utilization efficiency of the raw material gas TiCl ₄ is often extremely low, less than 1%.

On the other hand, when a TiN film is continuously coated while passing a plate of several thousand meters such as a metal strip, it is necessary to form a TiN film of about 1 μm in several minutes. It is desirable to use an area near the supply port where the film formation rate is high (see FIG. 1A).
However, if the average value of the film formation rate is taken in a relatively wide range from the source gas supply port to the exhaust gas outlet, the value becomes extremely low. Also, the raw material gas utilization rate is only about several percent at most.

In addition, as shown in FIG. 1B, when the source gas is blown by the nozzle, the film forming speed is dramatically increased immediately below the nozzle.
However, as the distance from the spray position increases, the TiN film formation rate rapidly decreases due to the reaction byproduct HCl. In addition, when a plurality of source gas spray nozzles are arranged in the direction of travel of the metal strip, the deposition rate is slightly increased, but new TiCl from the subsequent nozzle is successively added while the final reaction TiCl ₄ remains. _{Since 4} will be additionally supplied, the TiCl ₄ concentration in the reactor will increase more than necessary, and the raw material gas utilization efficiency will be significantly deteriorated. Furthermore, since TiCl ₄ is a highly corrosive gas, a large amount of equipment cost is required to install a plurality of supply pipes and nozzles.

Therefore, the inventors have conducted intensive studies on an appropriate gas supply method for increasing the deposition rate of TiN and further improving the utilization efficiency of titanium chloride such as TiCl ₄ .
As a result, in order to increase the utilization efficiency of titanium chloride, as shown in FIG. 1 (c), among the nozzles arranged in the traveling direction of the metal strip, the preceding nozzle (the first nozzle in this example) The titanium chloride-containing gas is sprayed onto the steel plate with the latter nozzle (in this example, the second and third nozzles), and the non-reacted titanium chloride is efficiently reacted to TiN by blowing a gas that does not contain titanium chloride. As a result, the present invention has been completed.

FIG. 2 shows the distribution of the TiN film thickness at each position of the steel plate when Ar gas is blown by the latter stage nozzle. As shown in the figure, the TiN film thickness increases at the position where Ar gas is sprayed.
Originally, the TiN film thickness decreases as it goes to the downstream side of the gas from the first nozzle position where TiCl ₄ was sprayed, as shown by the dotted line in FIG. 2, so Ti used as TiN is supplied TiCl It remained at a very low value of ₄ %. However, it was confirmed that the unreacted TiCl ₄ can be reacted with TiN again by blowing Ar gas that should not contribute to the reaction downstream of the gas.
This is an important finding that greatly improves the utilization efficiency of titanium chloride such as TiCl ₄ .

Further, when the type of gas blown from the rear nozzle was changed to hydrogen gas or nitrogen gas, as in the case of Ar gas, an increase in film thickness was confirmed in the vicinity of the blown position.
According to this method, the gas blown from the nozzle on the downstream side is not a titanium chloride, but may be a gas type normally used in an annealing line of metal strip such as hydrogen gas, nitrogen gas, and Ar gas. The use efficiency of the initially supplied titanium chloride can be effectively increased without the need for a gas supply pipe or nozzle.

The titanium chloride may be supplied alone, or nitrogen gas or hydrogen gas may be supplied as a carrier gas, or may be supplied in a mixture with atmospheric gas. That is, it may be supplied as a gas containing titanium chloride. At this time, the concentration of titanium chloride is preferably about 3% or more. Here, as the titanium chloride, titanium trichloride, titanium dichloride and the like can be used in addition to the above-mentioned titanium tetrachloride.
Further, as the gas type used for spraying the latter stage nozzle, any gas that does not contain titanium chloride, specifically, any gas that does not substantially inhibit the TiN formation reaction can be used. Examples thereof include gas, hydrogen gas, Ar gas, and other helium gas.
However, in consideration of the film formation rate, the raw material gas utilization efficiency, etc., it is particularly advantageous to use a nitrogen gas alone or a (nitrogen + hydrogen) gas in a combination of two or more gases.

  The principle of increasing the utilization efficiency of titanium chloride, which is a raw material gas, by blowing a gas that does not contain titanium chloride from the latter nozzle has not been clearly clarified yet, but is usually generated by a TiN film formation reaction. The HCl that stayed on the surface of the steel sheet significantly inhibited film formation on the downstream side of the gas, but the HCl was blown off by blowing nitrogen gas, hydrogen gas, Ar gas, etc. from the rear nozzle toward the steel sheet surface, As a result, it is considered that the inhibition factor of TiN generation has been removed and the film formation rate has been improved. In particular, it is considered that a more remarkable film formation reaction occurred when nitrogen gas containing a constituent element of TiN or nitrogen gas was mixed and sprayed with hydrogen gas that promotes reduction of titanium chloride. Therefore, it is particularly preferable to include hydrogen gas in the gas blown from the subsequent stage.

  In the present invention, when utilizing the gas spray from the latter nozzle, the spray speed is also an important factor. That is, when the gas spray speed of the rear nozzle is less than 0.5 m / s, no clear increase in the thin film is observed, whereas when it exceeds 50 m / s, the titanium chloride concentration in the vicinity of the steel sheet is extremely reduced. Will become thinner. Therefore, the spraying speed is preferably about 0.5 to 50 m / s for improving the utilization efficiency of the raw material gas.

  Moreover, the suitable example of the TiN continuous film-forming apparatus according to this invention is shown in FIG. In addition, in this example, although it showed about the case where the front stage nozzle which blows the gas containing a titanium chloride, and the back | latter stage nozzle which blows the gas which does not contain a titanium chloride for utilization efficiency improvement were each shown, this invention is shown. It is not restricted to this, About 1-5 back | latter stage nozzles can be arrange | positioned with respect to 1 front | former stage nozzle.

Furthermore, in the present invention, as shown in FIG. 4, a set of titanium chloride spray nozzles and subsequent spray nozzles for improving the utilization efficiency are set in the furnace gas flow direction. Also good.
Also in this case, it is preferable that the number of spray nozzles installed for improving the use efficiency is about 1 to 5 with respect to the number of titanium chloride spray nozzles installed in one set.

Example 1
A long steel plate is set in the reactor shown in Fig. 3 along the flow direction of the gas in the furnace, and TiCl ₄ is blown from the upstream nozzle on the upstream side at a furnace temperature of 1100 ° C using hydrogen gas as the carrier gas. A film was formed. At the time of this film formation, a comparison was made between the case where no gas was supplied and the case where nitrogen gas was blown at 9 m / s at the downstream nozzle on the downstream side of the gas. Here, TiCl ₄ was supplied to be about 1.0% of the atmospheric gas composition. After film formation for 2 minutes, a sample was taken out, and the TiN film thickness distribution at each position in the furnace was investigated.
The obtained results are shown in FIG.

As is clear from the figure, the film thickness monotonously decreased from the upstream nozzle supplying TiCl ₄ to the downstream side when no gas was blown from the downstream nozzle.
On the other hand, when nitrogen gas was blown from the rear stage nozzle, a significant increase in film thickness was observed immediately below the rear stage nozzle.
Taking the average in the film formation section from the reaction gas inlet to the outlet, when there was no gas blowing from the latter nozzle, the film formation rate was 0.31 μm / min and the TiCl ₄ utilization efficiency was 12%, When nitrogen gas was sprayed, a clear improvement effect was observed, with a film formation rate of 0.57 μm / min and a TiCl ₄ utilization efficiency of 20.3%.

Example 2
A long steel plate is set in the reactor shown in FIG. 3 along the flow direction of the gas in the furnace, and TiCl ₄ with hydrogen or nitrogen gas as a carrier gas from the upstream nozzle at the furnace temperature: 1100 ° C. In the downstream nozzle on the downstream side of the gas, the film was formed under the conditions where no gas was supplied and nitrogen gas, hydrogen gas, Ar gas alone or a mixed gas of these two kinds was blown at various speeds. The average concentration of the entire atmosphere was substantially constant at TiCl ₄ : 1.0%, hydrogen gas: 49%, and N gas: 50%.
In addition, a long steel plate is set in the reactor shown in FIG. 4 along the flow direction of the gas in the furnace, and hydrogen or nitrogen gas is supplied from the front nozzle in one set at a furnace temperature of 1100 ° C. as a carrier gas. TiCl ₄ was sprayed as a film, and film formation was performed under conditions where nitrogen gas, hydrogen gas, Ar gas alone or a mixed gas of these two kinds was sprayed at various speeds from the rear nozzle in one set. As in the case of FIG. 3, the average concentration of the entire atmosphere was set to be substantially constant, that is, TiCl ₄ : 1.0%, hydrogen gas: 49%, and N gas: 50%.
For each condition, the longitudinal TiN film thickness distribution of the steel sheet sample was measured, and the average film formation rate in the reaction zone was determined from the film thickness average value. Similarly, the utilization efficiency of TiCl ₄ was calculated from the TiN film thickness data.
The obtained results are shown in Table 1.

  As shown in the table, nitrogen gas is effective as the gas type used for blowing the nozzle of the latter stage nozzle, regardless of whether the reactor shown in FIG. 3 or the reactor shown in FIG. 4 is used. In particular, nitrogen gas and hydrogen gas are used. When mixing and spraying, the effect was the greatest. As for the spraying speed, good results were obtained when it was in the range of 0.5 to 50 m / s.

It is the figure which showed the change of the film-forming condition at the time of changing the gas supply method. It is the figure which showed the distribution state of the TiN film thickness in each position of the steel plate at the time of spraying Ar gas with a back | latter stage nozzle. It is the figure which showed the suitable example of the TiN continuous film-forming apparatus according to this invention. It is the figure which showed another example of the TiN continuous film-forming apparatus according to this invention. Is a diagram comparatively showing distribution of TiN thickness in the steel sheet each position in the case where blowing case and N ₂ gas without supplying a gas at a later stage nozzle.

Claims (6)

In the continuous processing line of the metal strip, when a reactive gas containing titanium chloride is supplied into the reaction furnace and a TiN film is continuously formed on the surface of the metal strip, A plurality of gas nozzles are arranged along the traveling direction, and among these gas nozzles, a gas containing titanium chloride is sprayed on the surface of the metal strip from the front stage to generate TiN at the spraying position , while the rear stage wherein the blowing gas containing no titanium chloride on the surface of the metallic strip from, TiN film formation method of the metal strip surface. In the continuous processing line of the metal strip, when a reactive gas containing titanium chloride is supplied into the reaction furnace and a TiN film is continuously formed on the surface of the metal strip, A plurality of gas nozzles are arranged along the advancing direction, and one or a plurality of gas nozzles that spray a gas containing titanium chloride and a gas that does not contain titanium chloride are subsequently blown out of the plurality of gas nozzles. A set of gas nozzles is used, and a plurality of sets are installed along the traveling direction of the metal strip, and the gas containing titanium chloride is sprayed on the surface of the metal strip to generate TiN at the spraying position. A gas stream containing no titanium chloride is blown onto the surface of the metal strip. A TiN film forming method on the surface of the cup.   3. The gas according to claim 1, wherein the gas not containing titanium chloride is one or more selected from nitrogen gas, hydrogen gas, and other gases that do not interfere with the TiN film forming reaction. TiN film formation method.   The TiN film forming method according to any one of claims 1 to 3, wherein a spray speed of the gas not containing titanium chloride is 0.5 to 50 m / s. A continuous TiN film forming apparatus for continuously forming a TiN film on a surface of a metal strip by supplying a reactive gas containing titanium chloride into a reaction furnace in a continuous processing line of the metal strip, A plurality of gas nozzles are arranged in the furnace along the traveling direction of the metal strip. Among these gas nozzles, a gas containing titanium chloride is sprayed on the surface of the metal strip in the previous stage , and then sprayed. An apparatus for continuously forming TiN on the surface of a metal strip, characterized in that a gas nozzle for generating TiN at a position is provided, and a gas nozzle for spraying a gas not containing titanium chloride on the surface of the metal strip is provided in the subsequent stage. A continuous TiN film forming apparatus for continuously forming a TiN film on a surface of a metal strip by supplying a reactive gas containing titanium chloride into a reaction furnace in a continuous processing line of the metal strip, In the furnace, a plurality of gas nozzles are arranged along the traveling direction of the metal strip. Among these gas nozzles, a gas containing titanium chloride is sprayed on the surface of the metal strip , and the sprayed position is reached. One gas nozzle for generating TiN and one or more gas nozzles for spraying a gas not containing titanium chloride on the surface of the metal strip are set as one set, and this set is set along the traveling direction of the metal strip. A TiN continuous film forming device on the surface of a metal strip, characterized by being installed.

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