JP3690828B2 - Abrasion-resistant ceramic coating on light metal support surface - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a ceramic coating on a light metal support surface. More particularly, the present invention relates to a ceramic coating on the surface of a light metal support excellent in wear resistance and durability.
[0002]
[Prior art]
As materials for general machine parts including sliding parts such as needle bars, presser bars and presser hugs for industrial sewing machines, various materials have been conventionally used in order to have excellent mechanical properties in use. Developed and used in practice.
[0003]
For example, carbon steel for machine structural use, nickel chrome steel, nickel chrome molybdenum steel, chrome steel, chrome molybdenum steel, etc. Some have hardened surfaces while retaining toughness inside. In addition, since the fatigue strength is improved because the compressive stress remains, it can be utilized not only for the sliding portion but also for the portion requiring fatigue resistance, but there is a drawback that oil leakage is likely to occur. . In the nitriding method, the material to be nitrided has been limited in the past, but in ion nitriding, a nitriding element is added to Ni, Cu, and Al, which is very difficult to nitride by the conventional nitriding method. Non-ferrous alloys and high alloy steels with high Cr content can be nitrided, and since nitriding is not hardened by quenching, it has the advantage of being less deformed than nitridated steel. Although it is often used recently as a material for machine parts, it has the same disadvantage as carburized steel that oil leakage is likely to occur. Therefore, for example, when these steel materials are used as sewing machine parts, oil leakage is likely to occur at the main sewing surface of the sewing machine. Carburized steel and nitrided steel are obtained by subjecting steel to surface hardening treatment, but because the specific gravity of the steel itself is large, the load on the entire machine cannot be reduced, resulting in undesirable phenomena such as heat generation due to friction. Occurrence could not be avoided significantly and oilless parts could not be made.
[0004]
By using light metal materials such as aluminum and aluminum alloy materials instead of steel as a support in response to demands for weight reduction, the necessary wear resistance and fatigue resistance are added by surface treatment of the light metal materials. It was proposed to try. One of them is to perform hard anodizing treatment on an aluminum material or an aluminum alloy material. In such a case, since aluminum is light, it has an advantage that the frictional resistance is reduced. However, the oxide film formed on the surface is liable to cause peeling of the oxide layer when used in a state of high stress load. Was accompanied. The above disadvantages were a very serious problem because baking would occur as soon as the film was lost due to peeling or abrasion. In addition, the fatigue resistance is lower than that of carburized steel or nitrided steel due to the hard treatment, and it cannot be used for portions that repeatedly receive large loads. Furthermore, cracks were likely to occur. And the hardness of the oxide film was obtained only about 500-700 in Hv.
[0005]
[Problems to be solved by the invention]
Therefore, an object of the present invention is to provide a material that is lightweight and has excellent wear resistance.
[0006]
Another object of the present invention is to provide a material that is lightweight and has excellent fatigue resistance.
[0007]
[Means for Solving the Problems]
As a result of earnest research, the inventor of the present invention combines the advantage that the specific gravity of the light metal is small and the wear resistance of the ceramic coating by using a light metal such as aluminum or aluminum alloy as a support and applying a ceramic coating thereon. We have succeeded in developing materials.
[0008]
This material is obtained by applying a wear-resistant ceramic coating on the surface of a light metal support, wherein a Ni-P intermediate layer is inserted between the surface of the light metal support and the ceramic coating. Material.
[0009]
Since the hardness of light metal and ceramic is very different, even if the ceramic coating is applied directly on the light metal support, the ceramic coating easily peels off with a small shear stress, but the Ni-P intermediate layer is separated from the surface of the light metal support and the ceramic. The problem of delamination was solved by inserting it between the film.
[0010]
The Ni-P intermediate layer may be deposited by either electroplating or electroless plating, but the one deposited by electroless plating is preferable because it has no pinholes and has a uniform thickness. In addition, since the nickel plating layer deposited by electroless plating is amorphous, it is heated to 400 ° C. or more and crystallized and stabilized. When aluminum or an aluminum alloy is used as a support, aluminum forms a strong oxide film that can be easily regenerated on its surface. Therefore, the Ni-P layer is plated after a special pretreatment such as displacement plating or direct plating. .
[0011]
Examples of the ceramic coating include a CrN film and a TiN film, but a CrN film is more preferable particularly for a blade. For the deposition of such a ceramic coating, it is preferable to use a vapor phase plating technique comprising PVD such as ion plating or CVD such as plasma CVD. In particular, ion plating has good adhesion, denseness, and tangling of the coating. Good because it is good.
[0012]
The light metal support includes aluminum, an aluminum alloy, magnesium, a magnesium alloy, and the like. From the viewpoint of good workability, an aluminum material or an aluminum alloy is preferable as a material for parts such as a presser bar of an industrial sewing machine.
[0013]
The film thickness of the Ni-P intermediate layer and the ceramic coating varies depending on the application and economy, but is generally 0.5 to 50 μm, preferably 10 to 20 μm.
[0014]
[Action]
Since the ceramic coating has higher hardness and excellent wear resistance at high temperatures than the light metal support, applying the ceramic coating to the light metal support keeps the friction coefficient small and significantly improves the wear resistance. Therefore, it is a member suitable as an oil-free sliding part. Further, when the coating is applied to the support, the adhesion becomes a problem. However, in the present invention, since the support, Ni-P intermediate layer, and ceramic coating have a three-layer structure, the hardness toward the surface is increased. It is considered that peeling of the ceramic coating is less likely to occur because of a stepwise increase and a thermal expansion coefficient that decreases stepwise. In addition, the load resistance against vertical force is significantly improved compared to the case where a hard anodizing treatment is applied to an aluminum material or an aluminum alloy material, so that not only sliding parts but also parts requiring fatigue resistance are required. Utilization is expected. Furthermore, the occurrence of cracks and a decrease in fatigue resistance associated with hard anodizing treatment on aluminum materials and the like were reduced.
[0015]
In addition, by using CrN having excellent heat resistance and corrosion resistance as the ceramic coating, the baking start time was greatly extended.
[0016]
【Example】
A light metal support with a wear-resistant ceramic coating, characterized in that a Ni-P intermediate layer is inserted between the surface of the light metal support of the present invention and the ceramic coating, and a hard anodizing treatment of the prior art. In order to compare the wear resistance and the coefficient of friction with the aluminum material applied thereon, the following tests were conducted.
[0017]
The sample shown in FIG. 1 is the sample used in the examples. In the sample of the present invention, a CrN film having a thickness of 20 μm was applied by ion plating on a support made of an aluminum material through an electroless plating Ni—P intermediate layer having a thickness of 20 μm. Moreover, the sample of the comparative example produced what gave the 40-micrometer-thick oxide layer by the hard anodizing process on the support body which consists of aluminum materials. Then, put each sample between the grips of the test apparatus shown in FIG. 2, slide it in the lateral direction, and slide it until seizure occurs and it does not move. Evaluated. The test conditions were all oilless 4000 RPM and a speed of 4.6 m / s.
[0018]
FIG. 3 shows the experimental results of the sample containing the CrN film of the present invention, and FIG. 4 shows the experimental results of the sample containing the hard anodic oxide film. As can be easily seen from the comparison between FIG. 3 and FIG. 4, the sample of the comparative example including the hard anodized film, although the baking load of the sample including the hard anodized film was significantly low, about 2 kgf, Baking occurred 20 minutes after the start of the test. On the other hand, with the sample of the present invention, when the load was 2 kgf, baking did not occur even after 20 minutes had elapsed, and after that, the load was increased to about 6 kgf and finally baking occurred after 6 hours from the start of the test.
[0019]
From the above, considering the wear resistance of the oxide film, it is considered that the oxide film peeled off before the abrasion of the oxide film progressed due to wear. On the other hand, the sample of the present invention has good adhesion of the ceramic coating and / or Ni-P intermediate layer and is prevented from being peeled off, has high wear resistance and low friction coefficient, and as a result, the baking start time is delayed. Moreover, it is considered that the seizure load was also increased.
[0020]
【The invention's effect】
Since the light metal support provided with the wear-resistant ceramic coating of the present invention is excellent in wear resistance and has a large seizure load, it can be used as a sliding part without lubrication or at a high speed. Also,
Further, since the vibration can be significantly absorbed by inserting the Ni-P intermediate layer, the use is expected also from the aspect of low vibration.
[Brief description of the drawings]
FIG. 1 shows the shape of a sample used in Examples.
FIG. 2 is a cross-sectional view of an apparatus used in Examples.
FIG. 3 is a diagram showing a baking time under a sliding test of a sample of CrN-coated Al material included in the scope of the present invention.
FIG. 4 is a diagram showing a baking time under a sliding test of a sample of an anodized Al material not included in the scope of the present invention.

Claims (2)

  A wear-resistant ceramic coating on the surface of a light metal support characterized in that a Ni-P intermediate layer is inserted between the surface of the light metal support and the ceramic coating, the ceramic coating comprising a CrN film and comprising a light metal support The body is a wear-resistant ceramic coating on the surface of a light metal support made of aluminum or an aluminum alloy.   The wear-resistant ceramic coating on the surface of a light metal support according to claim 1, wherein the Ni-P intermediate layer is deposited by an electroless plating method.

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