KR20040052533A - The Method of multiple-kinds-grain Titanium nitride (TiNx) synthesis on carbon steel (S45C) with maximal microhardness using surface density - Google Patents

Abstract

PURPOSE: A thin film preparing method for finding out the maximum micro-hardness of carbon steel (S45C) widely used as materials for machinery using physical thin film deposition method is provided. CONSTITUTION: The method for preparing a thin film having the maximum micro-hardness using surface density of composite grain (TiNx) when forming TiNx thin film on carbon steel is characterized in that micro-hardness of carbon steel (S45C) is improved up to the maximum 2.6 times by performing a physical thin film deposition method on the surface of the carbon steel (S45C), wherein the physical thin film deposition method comprises a process of preheating a matrix for the maximum 3 hours, a process of changing temperature of the matrix so that the maximum surface temperature of the matrix reaches 360 to 430 deg.C, a process of changing preparation time from 30 to 60 minutes, a process of maintaining pressure of nitrogen gas from 2.0x10¬-3 torr to 4.5x10¬-3 torr, a process of changing bias voltage from 250 to 880 V, and a process of changing magnetic field intensity for controlling plasma from 3 to 6.5 gauss. The apparatus for preparing a thin film having the maximum micro-hardness using surface density of composite grain (TiNx) when forming TiNx thin film on carbon steel comprises titanium cathode(1), tungsten trigger(2), permanent magnet(3), glass window(4), vacuum furnace (anode)(5), sample to be deposited (cathode)(6), sample holder(7), heater(8), gas injection port(9), vacuum pump(10) and sample rotation device(11).

Description

The method of multiple-kinds-grain Titanium Nitride (TiNx) synthesis on carbon steel (S45C) with maximal microhardness using surface density}

In the present invention, the preheating process is performed using a physical vapor deposition thin film which is manufactured in vacuum state by selecting 12 samples of carbon steel (S45C) that require relatively wear resistance and easy surface treatment among the 12 tire manufacturing machines. The carbon steel with the finer hardness was manufactured through a total of six steps including the process of changing the maximum surface temperature of the base metal, changing the manufacturing time, maintaining the nitrogen gas pressure, changing the bias voltage, and changing the magnetic field strength.

The rotating part of the conveyor is twisted even with a slight error, resulting in a defective product or a secondary process, which shortens the service life.Because the strength is different from other parts, the spring may splash or the pin may be overloaded, which may prevent the export from being pushed properly. For durability and compatibility, surface treatment to increase the wear resistance of this part is important.

Among the thin film manufacturing methods for improving the metal surface, the physical vapor deposition thin film is a method of attaching an ion source to a base material and is a core technology for semiconductor manufacturing. The application of a confining magnetic field to the ion plasma generated by the arc facilitates directionality, and the selection of a strong bias power source, an appropriate nitrogen gas pressure, and a substrate temperature are key to this invention. In this case, if the processing time is infinite, only manufacturing cost increases and thin film hardness is not effective. It has also been found that proper preheating of the base increases hardness.

The plasma ion source was made of stainless steel covering a titanium plate through which a 15 cm x 20 cm x 0.6 cm coolant with 99.5% purity was passed. The base material is inserted and rotated, and at the same time as the vacuum operation, it is heated by the resistance heating wire in the vacuum furnace and preheated to the appropriate temperature. At this time, if the bias voltage is applied between the base material (cathode) and the grounded vacuum furnace (anode), thin film deposition is performed on the base material and the most economical coating time must be found through several experiments. This is because the intensity remains constant after a certain time. When the arc ion is generated, the arc is generated by a trigger with a tungsten needle (a device that repeatedly touches and drops the titanium negative electrode plate) which is supplied with a constant power of 100 A and 20 V and a power supply of 100 A and 50 V. At this time, a plasma confined magnetic field is applied to induce a uniform arc to have a directivity. Because of the bias voltage, the ions are strongly embedded in the substrate and the electrons disappear into the ground along the vacuum path.

Typically, titanium nitride thin films have been mainly used in applications requiring wear resistance, such as tools and machinery. The application of this thin film to wear-resistant carbon steels extends the life of the machine and enables it to produce a uniform product even during continuous operation at high temperatures. This is a necessity for the production of conveyor parts that require ultra-precision at the time of the rapid development of conveyor technology to make expensive, precise and safe tires.

In order to improve the wear resistance of carbon steel (S45C), which is the most widely used metal material, the present invention aims to find the maximum microhardness state easily by investigating the composite grain surface density of TiNx when manufacturing a titanium nitride thin film using a physical vapor deposition thin film. .

In addition to the existing titanium nitride thin film manufacturing method, the preheating stage of the base metal and the introduction of magnetic lines for control were developed to develop an optimized equipment for increasing hardness with all six physical variables. When the thin film was made on the substrate, it was found that the temperature of the substrate was a very important parameter for uniform coating and preheated to 400 ° C. prior to operation of the device. In addition, in order to prevent the titanium ions due to the arc to form a turbulent flow to prevent uniform coating, the cyclotron movement was performed by applying a magnetic field to enable the Jay according to the direction. In addition, the optimum conditions for the thinnest thin film manufacturing are found by changing six physical variables by adding bias voltage, coating time, surface temperature, and gas pressure, which are often considered essential in the production of titanium nitride thin film. . In this case, if the manufactured sample is dependent on the hardness tester, a complicated process of comparing the hardness before and after the thin film for the same sample is required (measuring error is large and the measuring instruments vary depending on the hardness), but the composite grain surface of TiNx as in the present invention By investigating the density, it is easy to know the maximum microhardness state at once.

1 is a schematic representation of an apparatus using the method according to the invention

Figure 2 is a SEM photograph showing the surface density of the composite grain of TiNx prepared by the present invention

FIG. 3 is an enlarged SEM photograph of one thin film crystal among TiNx composite grains prepared according to the present invention. FIG.

<Explanation of symbols for the main parts of the drawings>

1: titanium negative plate

2: tungsten trigger

3: permanent magnet

4: glass window

5: vacuum furnace (anode)

6: film-film specimen

7: specimen holder

8: heater

9: gas inlet

10: vacuum pump

11: Specimen Rotator

Hereinafter, a method for quickly detecting a maximum microhardness in manufacturing a titanium nitride thin film for improving wear resistance of carbon steel according to the present invention will be described in detail with reference to the accompanying drawings.

A schematic diagram of an apparatus for implementing the method of the invention of FIG. 1 is shown. The device consists of a titanium negative electrode plate (1), a tungsten trigger (2) for arcing (2) and a vacuum furnace (5), and a permanent magnet array (3) attached at regular intervals to control the plasma ions generated at 1 (3). Glass window 4 and preheating ohmic heater 8 designed to inject various diagnostic equipment by monitoring the inside of the head), and 5, the base material specimen 6, its holder (7) and the rotating device (11), and It consists of an inlet (9) for supplying the gas in the interior of 5 and the vacuum pump (10) for maintaining the internal low vacuum pressure.

An embodiment of the method for determining the maximum microhardness state at a time by easily examining the composite grain surface density of TiNx using the above apparatus is as follows.

First increase the internal temperature of 5 to 400 ° C using 8 before starting the unit. Using a dispersion pump or turbo pump (10) with a nitrogen trap, the internal pressure of 5 was dropped to 1.5 × 10 ^-6 torr, and then a mixture of nitrogen (86%) and argon (14%) gas through 9 was carried out. Inject to increase the internal pressure of 5 to 2.0 × 10 ^-3 torr.

Titanium ions are generated by applying a uniform current of 20 volts 100 ampere to 1 and triggering Trigger 2 with a current of 50 volts 100 amps. At this time, the ions are bound by 3 and have a directivity without turbulent motion.

Put 6 in 7, run 11, and put a 250 volt vias between 1 and 6. From this time, the coating time starts. At this time, the infrared thermometer is launched from the outside to measure the base material temperature, and if necessary, the bias is adjusted once or twice more. Set the coating time to turn off the vias and quickly stop 2.

2 and 3 are SEM pictures of the composite grain of TiNx for the carbon steel (S45C) sample obtained through the present invention. FIG. 2 is an SEM photograph showing the surface density of the composite grain of TiNx prepared according to the present invention, and FIG. 3 is an enlarged SEM photograph of one thin film crystal among the composite grains of TiNx prepared according to the present invention.

As described above, in the present invention, a physical body manufactured in vacuum state by selecting 12 samples of carbon steel (S45C), which require relatively wear resistance and easy surface treatment, among conveyor parts, among 12 kinds of tire manufacturing machines such as a tread stitcher, etc. The deposited thin film method (Fig. 1) was used. The SEM image of the sample showed that the microhardness increased up to 2.6 times by investigating the surface density of TiNx composite grains. This method is less time consuming and more accurate and easier.

Claims (2)

A method of forming a maximum hardness of 2.6 times by performing physical vapor deposition thin film in six steps on the surface of carbon steel (S45C): Preheating process performed for up to 3 hours, and the highest base material from 360 ℃ to 430 ℃ Change of surface temperature, change of manufacturing time from 30 to 60 minutes, maintenance of nitrogen gas pressure from 2.0 × 10 ^-3 torr to 4.5 × 10 ^-3 tom, change of bias voltage from 250V to 880V, 3 gauss ~ 6.5 gauss plasma magnetic field change process. The method of claim 1, wherein the surface density (number per μm 2) of the composite grain is examined in the SEM photograph of the thin film manufactured through the six steps.