JPS6356306B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a surface nitriding apparatus for titanium products such as dental products.

[Conventional technology]

Conventionally, as a method for nitriding the surface of titanium products, there is a method for nitriding the surface of pure titanium or α-titanium alloy, as typified by, for example, Japanese Patent Publication No. 44148/1983. In this surface nitriding method, nitrogen gas is supplied while titanium nitride powder and pure titanium or α-titanium alloy are in contact with each other in one chamber, and the temperature is increased from 790°C to 880°C.
While heating the titanium product to a certain degree, the surface of the pure titanium to be treated is nitrided using titanium nitride powder that is present around the titanium product. Another method is gas nitriding, in which nitrogen gas is brought into contact with the titanium product to be treated under heated conditions.

[Problem that the invention seeks to solve]

However, the first method described above has the disadvantage that it takes a long time to process because titanium nitride is used to form nitrides on the surface of pure titanium or α-titanium alloy through mutual reaction. There is.
In addition, the second gas nitriding method requires large and costly equipment to remove oxygen and hydrogen present in nitrogen gas, making it difficult to achieve general low cost and general use. In a sense, it is a cause of hindrance. In particular, when hydrogen and oxygen components remain in the nitrogen gas, these may react with the pure titanium or alpha titanium alloy surface to be treated, changing the surface strength or changing the color from the desired color to another color. There is a tendency to change to

The present invention aims to simplify the conventional surface nitriding method for titanium products such as pure titanium and titanium alloys, which requires expensive and complicated equipment, and also to shorten the processing time. It is an object of the present invention to provide a nitriding apparatus for titanium products in which the surface condition of the nitrided titanium products is also good.

[Means for solving problems]

The nitriding apparatus for titanium products according to the present invention was invented in view of the above-mentioned problems, and it connects the inlet connected to the nitrogen gas supply means to the outlet connected to the vacuum means and discharges the gas. One gas flow path means is created, a gas distribution pipe with an opening on the outer peripheral surface is installed inside the container disposed in the gas flow path means, and a gas distribution pipe with an opening on the outer peripheral surface is installed between the gas distribution pipe and the inner surface of the container. The space is used as a nitriding titanium product placement area, and the distance between the nitriding titanium product installed in the product placement and the aperture surface of the gas distribution pipe is equalized, and the gas distribution pipe and product placement area are connected to the gas flow. A nitrogen gas filter having a built-in small piece of titanium or a small piece of titanium alloy is provided in the gas flow path as a part of the product placement part or independently of the product placement part, and the nitrogen gas filter and the titanium product for nitriding treatment are arranged. It is characterized in that a heating means is arranged in both parts.

[Effect]

The structure of the present invention is as described above, and the nitrogen gas continuously flowed by the nitrogen gas supply means and the vacuum means is heated by the heating means and built into the nitrogen gas filter provided in the flow path means. For nitriding treatment, the hydrogen and oxygen contained in the nitrogen gas are removed by bringing it into contact with a small piece of titanium or a small piece of titanium alloy, and then the nitrogen gas is heated to form a pure nitrogen gas and placed in the titanium product placement area. A titanium nitride product is obtained by contacting the surface of a titanium product to form a nitride layer on the surface.

〔Example〕

The details of the present invention will be further explained with reference to embodiments shown in the drawings.

FIG. 1 is an explanatory diagram of one embodiment of the present nitriding processing apparatus, in which a flange 4' is formed in a recess 2' provided on the upper surface of a substrate 2, and a flange 4' is formed outward at the lower end of a covered tube, as a processing furnace 1. is installed in a sealed state via a packing member 3 to form an exterior tube 4, and a support tube body 5 having a flange 5' formed outward from the upper end periphery is disposed at the center of the base plate 2 inside the exterior tube 4. A container 6 is provided on the upper end surface of the support tube 5, with the center of the bottom opening downward. Openings that communicate with each other are provided as an outflow port 8 and an inflow port 7, respectively, and a series from the inflow port 7 to the space between the outer pipe 4 and the container 6, through the container 6 and the support pipe 5, and to the outflow port 8. A gas distribution pipe 18 having an opening 19 on the outer peripheral surface is installed inside the container 6, and the gas distribution pipe 1
8 and the inner surface of the container 6 is used as a nitriding titanium product placement part a, and the gas distribution pipe 18 and the product placement part a are part of the gas flow path. Also, inlet 7
A nitrogen gas cylinder 1 is used as a nitrogen gas supply means.
0 is connected by a pipe 9 via a throttle valve 11, and a vacuum pump 12 and a pressure reducing pump 13 as vacuum means are connected to the outlet 8 through a valve 14 and a throttle valve 1, respectively.
5 and are connected by a pipe 16 so that the gas inside the processing furnace 1 can be sucked, forming a flow path through which nitrogen gas can be sequentially supplied from the nitrogen gas cylinder 10 into the processing furnace 1. Further, heating means 17 for heating the inside of the processing furnace 1 to the processing temperature is arranged around the exterior tube 4 inside the processing furnace 1. In this embodiment, the product placement part a in the container 6 is filled with titanium or titanium alloy small pieces, and the nitrogen gas filter f is
In addition, by embedding the titanium product T for nitriding treatment in the titanium or titanium alloy small piece, it is also used as a support member for supporting the titanium or titanium small piece as the nitrogen gas filter f in the titanium product placement part. .

The operation of nitriding a titanium product using the above-mentioned nitriding equipment is performed first by nitriding small pieces of titanium or titanium alloy filled in a container 6 serving as a nitriding titanium product placement part a and a nitrogen gas filter f. The titanium product T is buried so that the distance from the opening 19 provided in the gas distribution pipe 18 is approximately equal. Next, with the throttle valve 11 of the nitrogen gas cylinder 10 closed, the pressure inside the processing furnace 1 is reduced to high vacuum using the vacuum pump 12, and then the valve 14 is closed, and the throttle valve 11 is
is opened and nitrogen gas is filled into the processing furnace 1 from the nitrogen gas cylinder 10. This depressurization and nitrogen gas filling operation is repeated 2 to 3 times to eliminate as much air as possible inside the processing furnace 1, and the heating means heats the inside of the processing furnace 1 to a predetermined processing temperature, for example, about 700°C to 880°C. After adjusting the throttle valve 11 connected to the nitrogen gas cylinder 10 to supply nitrogen gas, at the same time operating the pressure reducing pump 13 while adjusting the throttle valve 15, the nitrogen gas is flowed under a reduced pressure of, for example, 300 to several Torr to perform nitriding. It performs processing. The nitrogen gas introduced into the processing furnace 1 from the nitrogen gas cylinder 10 through the inlet 7 is activated by being preheated by the heating means 17 around the outer tube 4, and first the nitrogen in the container 6 is activated. gas filter f
Impurities such as oxygen and hydrogen contained in the nitrogen gas are removed by contact with titanium or titanium alloy small pieces, and when it comes into contact with the titanium product T as pure nitrogen gas, it reacts with the surface of the titanium product, and the nitrogen gas reacts with the surface of the titanium product. A nitride film is formed on the surface of the titanium product T. Further, nitrogen gas is supplied by a nitrogen gas cylinder 10 as a supply means and a decompression pump 1 as a vacuum means.
By flowing through step 3, fresh nitrogen gas is always in contact with the titanium product, so that a better treated surface can be formed. By adjusting the nitrogen gas pressure during the treatment to 300 to several Torr as described above, the nitrided surface of the titanium product can be improved. In addition, as for the operating procedure, as mentioned above, at the beginning of the nitriding process, the pressure inside the processing furnace 1 is reduced to a high vacuum using the vacuum pump 12, and nitrogen gas is introduced, or nitrogen gas is introduced and passed through the processing furnace. A method of creating a nitrogen gas atmosphere inside 1 is adopted. In addition, the heating may be performed after the inside of the processing furnace 1 is made into a nitrogen gas atmosphere, or the inside of the processing furnace 1 may be heated in advance, and in this state, the titanium product T as a processing member is inserted, and the nitrogen gas atmosphere is It is also possible to supply it as desired. In this embodiment, by using a vacuum pump 12 and a decompression pump 13 together as vacuum means, nitrogen replacement in the processing furnace 1 at the start of processing can be quickly performed and the flow of nitrogen gas during processing can be easily adjusted. However, the vacuum pump 12 and the decompression pump 13 can also be used together in one pump. Furthermore, if the inside of the processing furnace 1 has a vertical double structure as in this embodiment, the preheating activation of the nitrogen gas by the heating means 17 and the reaction with the titanium product T can be made more effective. , the inside of the substrate 2 may have a water-cooled structure.

Here, the small titanium pieces or small titanium alloy pieces used as the nitrogen gas filter f must be of a size or shape that does not come into contact with the oxygen content in the nitrogen gas and burn when heated. That is, since nitriding usually starts at about 700°C, it is necessary that the titanium or titanium alloy small pieces be of a size that will not start burning due to contact with the oxygen content in nitrogen gas at about this temperature. Its size is about 100 meshes, but in order to make it easier for oxygen, hydrogen, etc. in the nitrogen gas to react with the titanium or ferrotitanium pieces as the nitrogen gas filter f from the surface of the titanium product, a nitrogen gas filter f is required. The temperature of titanium product placement part a
It is advantageous to set the temperature higher than , and therefore it is more preferable to use titanium or ferrotitanium pieces larger than 80 mesh. By using a material of this size, even if it comes into contact with nitrogen gas heated at a temperature higher than the nitriding temperature on the surface of the titanium product, it will come into contact with the oxygen and hydrogen components in the nitrogen gas and burn. It provides conditions sufficient to prevent this. Furthermore, when the nitrogen gas filter f is provided in the nitriding titanium product arrangement part a, the nitrogen gas passes between the titanium pieces or the titanium alloy pieces and easily comes into contact with the nitriding titanium product T. It is desired that the titanium pieces be as small as possible, that is, have good air permeability. In this sense, pieces larger than 60 meshes, e.g. 35
If a mesh or a small piece of about 10 mm is used, the initial temperature of titanium nitriding is about 700℃, and the deformation point is about 900℃.
Since the temperature is a little less than 0.degree. C., combustion will not start even if it comes into contact with nitrogen gas, and the life of these titanium or titanium alloy pieces as a filter can be extended, making this a more preferable usage mode. still,
As the titanium pieces, pure titanium plates, scraps, sponge titanium, etc. can be used, and as the titanium alloy pieces, ferrotitanium pieces etc. can be used.

In the above embodiment, the space inside the container 6 also serves as the nitrogen gas filter f and the titanium product placement part a, but as shown in FIG. The space between the container 6 and the container 6 may be filled with small pieces of titanium or small pieces of titanium alloy as a nitrogen gas filter f. In this case, as shown in FIG. 2, a granular, powder-like, or crushed piece-like member, such as quartz beads or crushed pieces, is placed around the titanium product T as a support member s in the titanium product placement part a. When the nitrogen gas contacts the titanium product T, it passes between the quartz beads and comes into contact with the titanium product T, so that the nitrogen gas contacts the entire surface of the titanium product T, resulting in a uniform nitrided surface. This produces the effect of obtaining a titanium nitride product with a better surface condition. In addition to the above-mentioned quartz beads or crushed pieces, such support members s may include materials that have heat resistance at a nitriding temperature of approximately 700 to 880°C or higher, such as granular materials such as alumina, ceramics, and Vycor glass (high silicate glass). , powdered or crushed pieces may be used, but if the material is porous and easily contains gas etc., those gases may come into contact with the titanium product for nitriding and react with the surface of the titanium product. It is excluded because it forms a film other than a nitride layer on the surface of a titanium product.

Further, the nitriding apparatus according to the present invention has a gas distribution pipe 18 in which the nitrogen gas after passing through the nitrogen gas filter f is provided with an opening 19 at an appropriate position in the side wall in the container 6 as the titanium product placement part a, as shown in the figure. interior,
By supplying nitrogen gas from this gas distribution pipe 18 to the titanium product placement part a, it is possible to uniformly contact the nitrogen gas to the front of the titanium product T, thereby forming a uniform nitride layer on the surface of the titanium product. can be formed. Also, as shown in Figure 2, the nitrogen gas filter f is placed in the titanium product placement area a.
If it is installed independently from the titanium product placement part a
By arranging support members such as quartz beads around the titanium product T in the interior, the contact of nitrogen gas to the titanium product surface can be made more uniform, and the treated surface can be made uniform and good. .

〔Effect of the invention〕

As described above, the titanium nitriding apparatus according to the present invention sequentially flows nitrogen gas from the nitrogen gas supply means through the gas flow path means to the vacuum means, and under heated conditions, the titanium or After contacting a small piece of titanium alloy to remove hydrogen, oxygen, etc. contained in the nitrogen gas, fresh nitrogen is constantly applied to the surface of the titanium product for nitriding placed in the titanium product placement area under heating conditions as pure nitrogen gas. By bringing the gas into contact with titanium products for nitriding,
A uniform nitride layer can be formed on the surface of the titanium product in a short time using a simple device, and a good titanium nitride product can be provided. Furthermore, by performing nitriding treatment by flowing nitrogen gas under reduced pressure, it is possible to improve the nitrided surface of titanium products, and to ensure that the nitrogen gas comes into uniform contact with the surface of titanium products through the openings of the gas distribution pipe. This allows a uniform nitride layer to be formed on titanium products.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing one embodiment of the nitriding apparatus for titanium products according to the present invention, and FIG. 2 is an explanatory diagram showing another embodiment of the inside of the processing furnace of the apparatus in FIG. 1: Processing furnace, 2: Substrate, 3: Packing member,
4: Exterior pipe, 5: Support tube, 6: Container, 7: Inlet, 8: Outlet, 9: Pipe, 10: Nitrogen gas cylinder, 11: Throttle valve, 12: Vacuum pump, 13:
Decompression pump, 14: Valve, 15: Throttle valve, 1
6: pipe, 17: heating means, 18: gas distribution pipe, 19: hole, T: titanium product, a: titanium product placement part, f: nitrogen gas filter, s: support member.

Claims (1)

[Claims] 1. Create one gas passage means from the inlet side connected to the nitrogen gas supply means to the outlet for discharging gas in relation to the vacuum means, and create a gas passage means inside the container disposed in the gas passage means. A gas distribution pipe with an opening provided on the surface is installed, and the space between the gas distribution pipe and the inner surface of the container is used as a titanium product placement part for nitriding treatment,
The distance between the titanium product for nitriding installed in the product arrangement and the aperture surface of the gas distribution pipe is made equal, and the gas distribution pipe and the product arrangement part are made part of the gas flow path, and the product arrangement part or A nitrogen gas filter incorporating a small piece of titanium or a small titanium alloy is provided in the gas flow path independently of the product placement part, and a heating means is arranged between the nitrogen gas filter and the titanium product placement part for nitriding. Product nitriding equipment.