JPS5916908A - Manufacture of ornamental alloy - Google Patents

Abstract

PURPOSE:To obtain the alloy having a combination of new color tone or new property arranged on a base plate, by carrying out hot hydrostatic treatment on the metal powder forming body after infiltration method is carried out for it on the base plate and both of them are fixed. CONSTITUTION:After compression molding the powder having a relatively high melting point, the previously sintered green compact is arranged on a base plate and the voids of previously sintered body is infiltrated with a metal having a low melting point. Thus, only if both metals are wettabile by each other and the difference of melting points is sufficient for the treatment, an optional combination of materials may be possible. Then, the infiltration method as well as the diffusion of said low melting point metal are carried out and the previously sintered body is fixed to the base plate. Because voids inside the previous sintered body can not be completely removed under this condition and the alloy is not suitable for ornament, the whole is treated with hot hydrostatic treatment to reduce the voids and to obtain the aimed alloy.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a decorative alloy that has increased added value by having unprecedented appearance and material properties.

In general, the main properties required for decorative alloys are: 111 Good surface gloss and long-lasting appearance 12 + No corrosion or discoloration depending on the usage environment 13
One color tone has characteristics, and the material itself has value +41 It does not crack or chip even if it falls during use (5) It has high added value and can be manufactured at low cost, etc. can be given.

Metals that satisfy each of the above (11 to +51) include Wc-based and T(Wc-based cemented carbide, Ni alloy, Co-based hard alloy, 18K, 14K, IOK alloy, smooth stainless steel, and four-plated steel. There are items etc.

These alloys are widely used in jewelry such as necklaces, earrings, rings, bracelets, watch cases, lighters, etc. However, as their decorative requirements have diversified, they have been There is a need for new materials that simultaneously satisfy the requirements listed above.

In order to meet these new demands, conventional melting,
There were technical limits to what could be achieved using methods that mainly involved casting and rolling, as well as ordinary surface treatment techniques.

The present invention is characterized by using an infiltration method, which is one of the powder metallurgy techniques, in order to solve the problem. The contents are as follows.

After compression molding the powder with a high melting point, the pre-sintered green compact is placed on the substrate, and the molten metal is infiltrated into the pre-sintered body using the infiltration method, and at the same time, it is diffused and fixed onto the substrate. The feature is that the entire product undergoes hot isostatic pressure treatment, which is used when sintering cemented carbide and ceramics.

The infiltration method referred to here means that after compression molding of powder with a high melting point,
This is a method in which a metal with a low melting point is melted and infiltrated into the voids of a pre-sintered powder compact, which has mutual wettability.
Any combination of materials is possible as long as they have a processable melting point difference.

However, simply infiltration treatment cannot completely remove the internal voids and is therefore unsuitable for decorative purposes, so it is necessary to perform hot isostatic pressure treatment to remove the voids. This method makes it possible to create infiltration coatings with new characteristics and combinations of materials with color tones that were previously impossible to achieve.

Examples are shown below.

Example I A mixed powder of TaC-5% by weight Nj-i and 5% by weight Ca (average particle size 2 μm) was heated at 800°C for 1 hour using HI Tor.
A temporary sintered body with a thickness of 0.5 mm was produced by sintering in a vacuum of r.

The porosity of this pre-sintered body was about 40 inches. After placing the pre-sintered body on a substrate made of low carbon austenitic stainless steel of 18C:r-sN= system, Au-2.5% by weight C1L was placed on top of this pre-sintered body. Plates with a thickness of 0.3 mm were placed and heated at 1000°C for 1 hour.
The infiltration treatment was carried out in a vacuum. During this infiltration, A u-C
A load of 1001/cm" is applied on the i alloy to promote infiltration. During this infiltration, the temporary sintered body is filled with metal, and at the same time, the A$-C% gold alloy is diffused into the stainless steel substrate. The pre-sintered body is bonded to the substrate at the same time.The pre-sintered body that has been infiltrated in the steps up to this point has some voids inside, and when the surface is polished, the voids are partially removed. Therefore, after infiltration, hot isostatic pressure at 900℃ and 500 atm is used for sintered cemented carbide and ceramic sintered materials. Hydrostatic pressure treatment was performed. When the substrate manufactured by this process was finished to a mirror finish using a diamond disk and diamond paste, the color tone was closer to real gold compared to conventional TaC-based cemented carbide. It was possible to easily make a cemented carbide containing gold alloy in the material itself.The material has a Vickers hardness of approximately 1000 to 1050, and is said to be permanently scratch-free when used with a pendant) K. In addition, we were able to create a product with a gold alloy surface layer that does not peel off.

Example 2 Mixed powder of w c -5 wt % CQ (average particle size of WC 0
．． 7 vx, average particle size of CO 2 μm) for 1 hour at 80°C, 1. Sintering was carried out in a vacuum of 1-" Torr. The porosity of this pre-sintered body was 50 cm. This pre-sintered body was , 5 wt% Cr-5, 5 wt% Fe - 4 wt% W, and a plate material of Au-5 wt% Ni is placed on top of this preliminary sintered body. set at 1150℃
The infiltration treatment was carried out for 1 hour in a vacuum of 10--TOrr. During this infiltration, the nickel alloy of the substrate and the AlL-N
4 gold alloy], a load of 100 S'/tyn'' was applied thereto.After this, hot isostatic pressure treatment was similarly performed at 1000°C and 500 atm.This material was treated in the same manner as in Example 1. When polishing was performed using the process, gold-colored Au-N was found in the Wc-based white carbide dispersed at approximately 0.771
<We were able to create a material in which a dichromatic cemented carbide, which has an appearance unprecedented in conventional alloys, is placed on a nickel substrate. The surface hardness was 1000, and when this alloy was used as a material for a lighter, it could be used as a hard precious metal that would not cause scratches.

Example 3 'rac - Mixed powder of 3 wt% N 6-2 wt% GO (T (average particle size of LC 0.5 m, Ni, CoO
Sintering was carried out at 850°C for 2 hours in a vacuum of 10-'' Torr.Au-40% by weight N7 alloy was similarly placed on the upper part of this preliminary sintered body, and the lower part T (zG - 5 wt % Ni - 2 wt % Cf cemented carbide placed at 1100°C for 1 hour), fl-" T or
Infiltration treatment was performed in a vacuum of γ. During this infiltration, hu
-100 f/(7) on top of N6 alloy! Infiltration was performed under a load of .

After this, hot isostatic pressure treatment was performed in the same manner. When this material was polished using the same process as in Example 1, Ta
We were able to create a two-color cemented carbide with an unprecedented appearance, consisting of a C-based amber alloy and a white alloy of fi and u -40% ui. This surface hardness was 1050 on the Vickers scale, and when a material made of polished cemented carbide was used as a watch case, it could be used as a scratch-free bicolor alloy.

Example Pd-20 wt% Ni alloy powder (average particle size 1 m) was
Sintering was performed at 00° C. for 1 hour in a vacuum of −37 Orr. This pre-sintered body is placed on 18Cr-sNi low carbon austenitic stainless steel, and Au-
A 10% by weight Cu alloy was placed, and infiltration treatment was performed at 1050°C for 0.5 hours in a vacuum of -'TOrr. Similar to the above example, a load of 50 V/cm'' was applied during infiltration, and after infiltration, HIP treatment was performed at 950 °C and 400 atm. This alloy was polished using sandpaper and puff. We were able to create a new appearance with a mixture of white Pd-Nt gold alloy and Au-Cit alloy, with no clear boundaries between the two phases.This material can be used for watch cases, bands, etc. It was ideal for new materials for exterior parts, pressed threads, and rings.

As mentioned above, the decorative alloy produced by the method of the present invention has most of the properties required for decorative materials, and it is also possible to create alloys with new appearances and properties that were not possible to produce using conventional methods. did.

In addition, the porosity of the present invention immediately after preliminary sintering is preferably 1
0-70Vo1. %, more preferable tL<h30~50Voj
, %, preferably low melting point metal in the finished product.
0 to 60 wt%, preferably 1-t25 to 45 wt%
It is.

that's all

Claims (1)

[Claims] After compression molding a powder with a relatively high melting point, a pre-sintered compact is placed on a substrate, and a metal with a low melting point is melted and infiltrated into the voids of the pre-sintered body, and at the same time, the metal with a low melting point melts and infiltrates. A method for producing a decorative alloy, which comprises fixing a pre-sintered green compact to a substrate and then subjecting the entire body to hot isostatic pressure treatment.