JPS62218567A - Wear-resistant article having tungsten carbide layer and its production - Google Patents

Abstract

PURPOSE:To manufacture the titled article excellent in wear resistance, by binding, via a palladium layer of a specific thickness, a tungsten carbide layer onto the nickel phosphide layer formed on the surface of a metallic base material. CONSTITUTION:Electroless plating is applied to the surface of the base metal such as cast iron, aluminum metals, etc., by use of nickel chloride and hypophosphite to form a nickel phosphide layer of about 1-15mu thickness. Then, electroless plating is applied onto the above nickel phosphide layer by the use of an aqueous solution of palladium chloride and a reducing agent to form a palladium layer of 100-1,000Angstrom thickness. Further, a tungsten carbide layer of about 3-20mu thickness is chemically vapor-deposited on the above palladium layer by the use of a gaseous mixture of tungsten hexafluoride, hydrocarbon, and hydrogen gas by means of gas-phase reaction. In this way, peeling-off of tungsten carbide layer is prevented, so that wear-resistant articles can be manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a wear-resistant article having a tungsten carbide layer and a method for manufacturing the same.

(Prior Art) As a wear-resistant article having a tungsten carbide layer, a die type is known in which a nickel phosphide layer having a hardness intermediate between the steel base material and the tungsten carbide layer is provided between the steel base material and the tungsten carbide layer. For example, see Japanese Unexamined Patent Publication No. 52-89583).

The above die mold is produced by, for example, forming a nickel phosphide layer by immersing a steel die material activated by a catalyst in an aqueous solution containing nickel ions and a phosphorus-containing reducing agent, and then using a chemical vapor deposition method to form a nickel phosphide layer. It is manufactured by a method in which a tungsten carbide layer is formed on the surface of a nickel phosphide layer using a gas phase reaction in a furnace.

Although the surface hardness of such wear-resistant articles is slightly lower than that of those in which the wear-resistant layer is formed with titanium carbide, the chemical vapor deposition treatment described above can be performed at a relatively low temperature, so that thermal deformation of the base material is avoided. Suitable when wear resistance and dimensional accuracy are required. However, when a tungsten carbide layer is formed on a nickel phosphide layer, the nickel phosphide layer forms an extremely thin oxide film after plating, and this oxide film causes the nickel phosphide layer to overlap with the tungsten carbide layer. There is a problem in that the adhesion between the tungsten carbide layer and the tungsten carbide layer deteriorates, and the tungsten carbide layer tends to peel off.

(Object of the Invention) In view of the above, the present invention provides a wear-resistant article having a tungsten carbide layer that has improved bonding strength to the nickel phosphide layer formed on the surface of a metal base material, and a method for manufacturing the same. This is what I am trying to do.

(Structure of the Invention) The wear-resistant article having a tungsten carbide layer of the present invention has a nickel phosphide layer formed on the surface of a metal matrix and the tungsten carbide layer as a wear-resistant layer having a thickness of 100 mm to 100 mm. It is characterized by being bonded via a 1000 Å palladium layer.

In addition, the above-mentioned method for manufacturing the wear-resistant article includes forming a nickel phosphide layer on the surface of a metal base material by electroless plating using nickel ions and a phosphorus-containing reducing agent, and then forming a nickel phosphide layer on the surface of the metal base material using palladium plating. A palladium layer with a thickness of 100 to 1000 thick is formed on the surface of the nickel oxide layer, and then a tungsten carbide layer is formed on the surface of the palladium layer by chemical vapor deposition.

As the metal constituting the base material, iron-based metals such as cast iron and steel, aluminum-based metals (including alloys), etc. can be used.

The nickel phosphide layer is a layer of a binary alloy of phosphorus and nickel, and can have a thickness of, for example, 1 to 15 μm.

Further, the tungsten carbide layer is a layer containing tungsten carbide, and can have a thickness of, for example, 3 to 20 μm.

The palladium layer covers the surface of the nickel phosphide layer to prevent the surface of the nickel phosphide layer from being oxidized, and is located between the nickel phosphide layer and the tungsten carbide layer to enhance adhesion between the two. In this case, if the thickness of the palladium layer is less than 100 mm, effective oxidation prevention cannot be obtained, and if the thickness exceeds 100 mm, this palladium layer may be replaced by a thermoset nickel phosphide layer or tungsten. Since the tungsten carbide layer is softer than the carbide layer, a problem arises in that the peeling resistance of the tungsten carbide layer against external stress is reduced. The adhesion between the nickel phosphide layer and the palladium layer and the adhesion between the palladium and tungsten carbide layers are higher than the adhesion between the nickel phosphide layer and the tungsten carbide layer.

Further, in the case of the manufacturing method of the present invention, in the electroless plating treatment for forming the nickel phosphide layer, nickel chloride or nickel sulfate, for example, can be used as the nickel ion, and hypophosphorous acid, for example, can be used as the phosphorus-containing reducing agent. Salt can be used.

Further, as the palladium plating process, for example, electroless plating process using an aqueous solution of palladium chloride and a reducing agent can be adopted. Further, chemical vapor deposition can be carried out by a gas phase reaction using, for example, a mixed gas of tungsten hexafluoride, hydrocarbon, and hydrogen gas.

In the above manufacturing method, nickel ions are reduced and precipitated on the surface of the base material as a binary alloy of N1-P to form a nickel phosphide layer, and are simultaneously heated during the chemical vapor deposition of tungsten carbide. Cures, maximum Hv 1
It reaches a hardness of about 100. By forming the palladium layer on the surface of the nickel phosphide layer, the tungsten carbide layer can be formed while preventing the surface of the nickel phosphide layer from being oxidized.

(Effects of the Invention) Therefore, according to the wear-resistant article having a tungsten carbide layer of the present invention, since the bonding force between the nickel phosphide layer and the tungsten carbide layer is increased by the palladium layer, external stress causes tungsten carbide to Improves the durability of wear-resistant articles by preventing layers from peeling off, allowing for aluminum extrusion dies, air plug gauges, journal gas bearings, aluminum die-cast injection plungers, and can manufacturing without the risk of unforeseen contingencies caused by delamination. It can be used for can lid tightening tools, etc.

Further, according to the manufacturing method of the present invention, it is possible to reliably obtain a wear-resistant article in which the tungsten carbide layer and the nickel phosphide layer are bonded via the palladium layer, and the surface of the nickel phosphide layer is The tungsten carbide layer can be formed by chemical vapor deposition without forming an oxide film.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the structure of the surface layer of the wear-resistant article 1. As shown in FIG. In the figure, 2 is the metal base material, 3 is the nickel phosphide layer formed on the surface of the base material 2, 4 is the palladium layer formed on the surface of the nickel phosphide layer 3, and 5 is the palladium layer 4. This is a tungsten carbide layer formed on the surface.

The base material 2 is made of alloy tool steel (SKDII), the thickness of the nickel phosphide layer 3 is 3 μm, the thickness of the palladium layer 4 is 200 μm, and the thickness of the tungsten carbide layer 5 is 7 μm.
It is.

As shown in FIG. 2, the wear-resistant article 1 includes a surface conditioning process of the base material 2, a catalytic process of the surface, an electroless plating process of nickel phosphide, an electroless plating process of palladium, and a process of tungsten carbide. Formed by sequential chemical vapor deposition steps. Each of these steps will be explained in order below.

The surface conditioning step is performed by cleaning and degreasing the surface of the base material 2, and then subjecting it to shot blasting. The purpose of this shot blasting is to improve the adhesion of the nickel phosphide layer 3 to the base material 2.

The above-mentioned surface catalytic process is a process of providing the base material 2 with catalyst nuclei for starting the reaction of electroless plating, and
By immersing the base material 2 in a palladium chloride aqueous solution,
Activate the surface of. In this catalytic process, noble metals other than palladium may be used.

The electroless plating process for forming the nickel phosphide layer 3 consists of nickel chloride (30gΩ-''), sodium hypophosphite (10gQ-'), and sodium citrate (100gQ-'').
Q-'), p containing ammonium chloride (50 gM-')
H8-10 (adjusted with NaOH), the base material 2 is immersed in a bath at a temperature of 40° C. for 30 minutes. This results in
The nickel ions are reduced, and nickel phosphide containing 5 to 15% phosphorus is deposited on the surface of the base material 2 to form a nickel phosphide layer 3.

The electroless plating process for forming the palladium layer 4 is as follows:
This is carried out immediately after the previous electroless plating of nickel phosphide. This is done by soaking for ~4 minutes. As a result, palladium ions are reduced and deposited as palladium on the surface of the nickel phosphide layer 3, forming the palladium layer 4.

In the chemical vapor deposition process for forming the tungsten carbide layer 5, after inserting the plated material into a chamber, the temperature inside the chamber is raised to 300 to 600°C, preferably about 400°C, and The pressure is reduced to 10 t, orr to 200 torr using an exhaust pump. Immediately, a mixed gas containing tungsten hexafluoride, hydrocarbon, and hydrogen gas is introduced into the chamber, and a tungsten carbide layer 5 is deposited on the surface of the palladium layer 4 by a gas phase reaction.

However, in the above manufacturing method, the nickel phosphide layer 3
has a hardness of Hv100 to 300 after plating.
However, when the tungsten carbide layer 4 is coated, it is thermally hardened to a high hardness close to Hv], lOO.

Now, FIG. 3 shows the wear-resistant article 1 of the above example.
FIG. 4 is a photograph (magnification: 10x) showing the surface condition of the results of an adhesion test (three-point bending test) of the tungsten carbide layer on conventional wear-resistant articles. In this case, the composition of each sample material is as shown in the table below.

1. The nickel phosphide layer and the tungsten carbide layer of the conventional example were each formed by the same treatment as in the example.

No cracks are observed in the example shown in FIG. 3, but a large number of cracks are observed in the conventional example shown in FIG. 4 around the raised edges.

Therefore, it can be seen that when a palladium layer is formed between a nickel phosphide layer and a talegesten carbide layer as in the present invention, the adhesion of the tungsten carbide layer becomes higher than when this palladium layer is not provided. . The reason is that the formation of the palladium layer prevents the formation of an oxide film on the surface of the nickel phosphide layer, and the palladium layer itself is difficult to oxidize. This is believed to be due to the high adhesion to the carbide layer.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view showing the surface layer structure of a wear-resistant article according to an embodiment of the present invention, FIG. 2 is a manufacturing process diagram of the same wear-resistant article, and FIGS. 3 and 4 are an example and a conventional It is a micrograph showing the surface condition of the tungsten carbide layer after adhesion test of each example. 1... Wear-resistant article, 2... Base material, 3
...Nickel phosphide layer, 4...Palladium layer, 5...Tungsten carbide layer. Figure 1 $ 2 Drawing Procedure Amendment (Method) June 20, 1988 Patent Application No. 60245 of 1988 2, Title of Invention Wear-resistant article having tungsten carbide layer and manufacturing method thereof 3, Amendment Relationship with the case of the person who filed the patent application Address of the patent applicant: 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Name (313)
) Mazda Motor Corporation Representative Ken Yamasui-4, Agent 650 Address Asahi Seimei Sannomiya Building 1-3-11 Ninomiya-cho, Chuo-ku, Kobe, Hyogo Prefecture Procedural Amendment 5, Date of Amendment Order May 7, 1986 (Delivery date 61.5.27) 6. Column 7 for a brief explanation of drawings in the specification subject to amendment. J is added. 5. Date of amendment order Michibu Uga, Commissioner of the Patent Office, Patent Application No. 60245, filed in 1988. 2. Title of invention: Wear-resistant article having tungsten carbide layer and method for manufacturing the same. 3. Amendment. Relationship with the case of a person who does
) Mazda Motor Corporation Representative Ken Yamasui-4, Agent 650 Address Asahi Seimei Sannomiya Building, 1-3-11 Sannomiya-cho, Chuo-ku, Kobe, Hyogo Prefecture Telephone: Kobe (078) 332-2671 (Representative) - Ichida Name (6873) 1) Medium Qing −3′gi, negative” 7. Add "of the metallographic structure of" next to "surface" on page 10, line 20 of the statement of contents of the amendment. that's all

Claims (2)

[Claims] (1) An article having a metal base material and a tungsten carbide layer as a wear-resistant layer, in which a nickel phosphide layer is formed on the surface of the base material, and the nickel phosphide layer and the tungsten carbide layer The thickness is 100~1000
A wear-resistant article having a tungsten carbide layer, characterized in that the tungsten carbide layer is bonded through a palladium layer of . (2) A nickel phosphide layer is formed on the surface of the metal base material by electroless plating using nickel ions and a phosphorous-containing reducing agent, and then palladium plating is performed to coat the surface of the nickel phosphide layer with 100% A method for manufacturing a wear-resistant article having a tungsten carbide layer, comprising forming a palladium layer of ~1000 Å and then forming a tungsten carbide layer on the surface of the palladium layer by chemical vapor deposition.