JP2969291B2 - Abrasion resistant member and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wear-resistant member having a titanium compound layer and an alumina coat layer formed on the surface of a substrate, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, the surface of a hard sintered alloy is coated with, for example, titanium nitride, titanium carbonitride, titanium carbonitride, etc. to improve its wear resistance and improve the cutting life. The technique described above is known as disclosed in JP-A-55-83507.

That is, since ceramics are hard and have excellent chemical stability, they are known to exhibit good wear resistance. However, since they are brittle, their application range as an actual wear-resistant member is limited. I have. Therefore, the gas phase synthesis reaction (CV
D) method was devised, and TiC, TiN
It is used as a method to extend the life of molds and cylinders by coating with a ceramic coating.

[0004]

However, in the ceramic coating technique as described above, the CVD method
Since the treatment is performed at a high temperature of 1000 ° C. or higher, there is a problem that the structure of the base material is adversely affected by heat when coating with a general iron-based metal.

[0005] In addition, the ion plating method and the plasma CVD method, which can perform coating treatment at a relatively low temperature, have a low adhesion strength between the base material and the coat layer, and thus are limited to applications where the load is small. And the multilayer coating of the titanium compound and alumina has high hardness and excellent wear resistance, but the titanium compound layer and the alumina coat layer have low mutual adhesiveness, and the peeling is likely to occur and the coating is excellent. It is difficult to form a coat layer, which is a major obstacle to practical application.

That is, when alumina coating is performed on the titanium compound layer, the thermal expansion coefficient differs between the two, and the gas composition of the coating is different.
An oxide is generated in the titanium compound layer at the time of alumina coating, which causes a decrease in the adhesion strength between the two.

In view of the above circumstances, the present invention provides a wear-resistant member in which an alumina coat layer is formed with a strong adhesion strength on a titanium compound layer formed on the surface of a substrate, and a method for producing the same. It is the purpose.

[0008]

In order to achieve the above object, a wear-resistant member according to the present invention comprises an alumina coat layer formed on a titanium compound layer formed on the surface of a substrate via a reaction layer of aluminum titanate. It is coated. The titanium compound layer is formed of TiC, TiN, TiCN, or the like.

[0009] In addition, a method for producing a wear-resistant member is to coat a titanium compound layer on the surface of a base material, apply an alumina coating to cover the alumina coat layer, and then heat in a non-oxidizing atmosphere. A reaction layer of aluminum titanate is formed between the titanium compound layer and the alumina coat layer.

[0010] Further, the above-mentioned wear-resistant member is produced by coating a titanium compound layer and an alumina coat layer on the surface of a base material in a vapor phase synthesis reactor, and then heating the titanium compound layer in a non-oxidizing atmosphere. A reaction layer of aluminum titanate may be formed between the layer and the alumina coat layer by continuous processing.

[0011]

In the above-described wear-resistant member and the method of manufacturing the same, an alumina coat layer is coated on a titanium compound layer coated on a substrate, and aluminum titanate is heated between the two layers by heating in a non-oxidizing atmosphere. By forming the reaction layer described above, the titanium compound layer and the alumina coat layer are coated with firm adhesion strength, and excellent wear resistance can be obtained. That is, the titanium compound layer is easily oxidized and deteriorated when the temperature is raised by the friction temperature or the like, but the titanium compound layer can be protected by laminating the alumina coat layer with good adhesion strength to improve heat resistance. .

Further, if the formation of the above-mentioned reaction layer of aluminum titanate is carried out continuously in a gas phase synthesis reactor, coating with even better characteristics can be performed.

[0013]

EXAMPLE In this example, a TiC coating layer was formed as a titanium compound layer on the surface of a cemented carbide.

First, as shown in FIG. 1, the structure of the wear-resistant member manufactured in this embodiment is such that a titanium compound layer 11 (TiC coat layer) is formed on the surface of a base material 10, and this titanium compound layer 11 is formed. An alumina coat layer 12 is laminated thereon via a reaction layer 13 made of aluminum titanate.

The manufacturing method will be described first.
Apply TiC coating on the surface of cemented carbide equivalent to 10 by plasma CVD method (plasma gas phase synthesis reaction method),
A titanium compound layer 11 (TiC coat layer) is formed. The TiC coat layer 11 is formed by using a chemical vapor synthesis (CVD) apparatus at a pressure of 60 torr under a pressure of 5% by volume of TiCl ₄ ,
A reaction gas containing 5% by volume of H _{4 and} 90% by volume of H ₂ is introduced, heated to 900 ° C., and reacted for about 2 hours to form Ti on the surface.
A C coat layer was formed. The thickness of this TiC coat layer was about 2 μm.

Subsequently, Al ₂ O ₃ coating is performed by the same CVD apparatus to form an alumina coat layer 12. This alumina coating is composed of 5% by volume of AlCl ₃ , C
O ₂ is 5% by volume, H ₂ is 90% by volume, and the reaction gas is 10%.
The mixture was heated to 00 ° C. and reacted for about 2 hours to form an alumina coat layer 12 on the surface. The thickness of the alumina coat layer 12 was about 2 μm.

Further, the material after the above-mentioned alumina coating is heat-treated in a reduced-pressure atmosphere, thereby reacting and producing aluminum titanate to form a reaction layer 13.
This heat treatment was performed by heating at a temperature of 900 ° C. for 60 minutes. If the temperature change of this heat treatment is shown in more detail in FIG. 2, heating is started in a vacuum atmosphere, the temperature is increased at a heating rate of 10 ° C./min, and when the temperature reaches 900 ° C., the temperature is maintained for 60 minutes, and then gradually. Then, the gas is purged by releasing the vacuum state during the slow cooling.

Next, test results of the adhesion strength of the above-mentioned coat layer are shown together with comparative examples. This adhesion strength test is carried out by a known scratch tester, and the scratch tester presses and moves the diamond scratched portion with respect to the test piece while gradually increasing the load. From the relation of the load, the adhesion strength is evaluated by the magnitude of the load at the time of peeling (Newton). Further, as a comparative example, a material after coating without performing the heat treatment for forming the reaction layer.

The result of this adhesion test, that is, the load [N] at the time of peeling, is the product of this embodiment: 60 [N], the comparison product: 40 [N], and the one according to this embodiment has significantly higher adhesion strength. Have. Also, when observing the scratch test marks, the boundary between the TiC coat layer 11 and the alumina coat layer 12 was unclear in the product of the present example in which the reaction layer 13 of aluminum titanate was formed by heat treatment. The peeling occurred at the boundary in the comparative product which was not subjected to the above, and a clear difference was observed in the adhesion. This was also confirmed by observation of the structure of the cross section with an electron scanning microscope.

As an attempt to further improve the adhesion of the alumina coat layer 12, the results of measuring the adhesion strength when the heat treatment conditions were set to 2 hours or 3 hours and the processing temperature was set to 1050 ° C. and 1200 ° C. 3 and 4
Shown in FIG. 5 shows the measurement results of the AE waveform in the scratch test at this time.

From the above test results, the abrasion resistance is higher than that of the untreated product at any temperature of 900 ° C., 1050 ° C., and 1200 ° C. (processing time: 2 hours). The optimal treatment temperature is in the range of 700 ° C to 1200 ° C. At lower temperatures, the reaction progresses slowly.
At a high temperature, the coat layer deteriorates, which is not preferable. The processing time (FIG. 4) when the processing temperature was 900 ° C.
Although the wear resistance has improved over 1 hour or more than the untreated product,
In 3 hours, the abrasion resistance is lower than in 2 hours. In the case of such a material or the like, about 2 hours is optimal.

On the other hand, as for the atmosphere, as shown in the AE waveform in FIG. 5, the Ar gas b at 900 ° C. × 2 hours under the heating condition with respect to the alumina peeling point Pa and TiC peeling point Qa of the untreated product a. Cooling alumina exfoliation point Pb and TiC
Separation point Qb, N ₂ alumina peeling point Pc and TiC separation point Qc of the gas cooling of c is high, the wear resistance is improved. The processing atmosphere is vacuum, Ar gas, H
It is most preferable in e gas, and in N ₂ gas, a reaction with alumina occurs, which is not preferable.

The conditions for coating the wear-resistant wear member and the conditions for forming the reaction layer are as follows. First,
The formation of the TiC coating layer 11 is as follows: (1) Thermal CVD method Titanium chloride (TiCl ₄ ), methane (CH
₄ ) A hydrogen (H ₂ ) gas is introduced and heated to 900 to 1050 ° C. under atmospheric pressure from several torr to form a TiC coat layer. At this time, the carrier gases are Ar, He and N _2. However, Ar or He is desirable from the viewpoint of film quality. Benzene or propane may be used instead of methane. TiCl ₄ + CH ₄ + H ₂ → TiC + HCl (2) Plasma CVD method The energy to be applied for coating is excited not only by heat but also by generating a plasma by generating a plasma,
The above reaction can be promoted. There is no need to apply heat by the amount of energy applied by the plasma. In this method, it is only necessary to heat to 400 to 900 ° C. Note that the pressure needs to be maintained at several torr or less in order to generate plasma.

On the other hand, the reaction gas for forming the alumina coat layer 12 is AlCl ₃ , CO ₂ , H ₂ as described above.
These gases are heated to 800-1100 ° C.
In the case of VD, it is necessary to use Al (CH ₃ ) ₃ and N ₂ O as gas components.

Further, in order to form the reaction layer 13 between the TiC coat layer 11 and the alumina coat layer 12, it is necessary to have a certain high temperature, but if the temperature is too high, abnormal growth of crystals in both coat layers will occur. It is not preferable. In addition, the atmosphere is preferable because the Ar or He gas does not affect each film. The best temperature condition is around 900 ° C.

In the heat treatment after coating in the above embodiment, a reaction layer of aluminum titanate is formed between the titanium compound layer and the alumina coat layer by the heat treatment. It becomes a coat layer which is excellent in abrasion resistance which is bonded and is not easily peeled off.

In the above embodiment, a cemented carbide is used as the base material. However, the present invention can be applied to other ferrous base materials. Further, as the titanium compound, the aforementioned Ti
In addition to C, TiN, TiCN, etc. can be coated by changing the reaction gas. Furthermore, the wear-resistant member according to the present invention can be applied not only to cutting tools but also to sliding sliding members such as rocker arm tips and camshafts of engines.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view of a wear-resistant member of the present invention.

FIG. 2 is an explanatory view showing an example of a heat treatment.

FIG. 3 is an explanatory diagram showing a relationship between heat treatment temperature and wear resistance.

FIG. 4 is an explanatory diagram showing the relationship between the processing time of heat treatment and wear resistance.

FIG. 5 is a graph showing a measurement result of an AE waveform with respect to an atmospheric gas;

[Explanation of symbols]

 10 Base material 11 Titanium compound layer 12 Alumina coat layer 13 Reaction layer

Claims (3)

(57) [Claims] 1. An abrasion-resistant member, wherein an alumina coat layer is coated on a titanium compound layer formed on the surface of a base material via a reaction layer of aluminum titanate. 2. After coating the surface of the substrate with a titanium compound layer, apply an alumina coating to cover the alumina coat layer, and then heat in a non-oxidizing atmosphere,
A method for producing a wear-resistant member, comprising forming a reaction layer of aluminum titanate between a titanium compound layer and an alumina coat layer. 3. A titanium compound layer and an alumina coat layer are coated on the surface of a substrate in a gas phase synthesis reactor, and then heated in a non-oxidizing atmosphere to form a space between the titanium compound layer and the alumina coat layer. A method for producing a wear-resistant member, comprising forming a reaction layer of aluminum titanate by a continuous treatment.