JPH0532033A - Seal - Google Patents

Abstract

(57) [Summary] [Structure] At least the printing surface of the stamp has TiN or TiC as a main component, and the average crystal grain size is 3 μm or less.
It is composed of a sintered alloy having a porosity of 0.3 to 5%. [Effect] A clear and elegant gold / silver-colored mirror surface is easily revealed, and it has excellent strength and chipping resistance.
It is possible to provide a seal stamp that has excellent features such as easy sharp edge processing, good porcelain paste, and no corrosion or flaws for a long period of time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seal stamp, and more particularly to a seal stamp having high strength, excellent workability, and improved corrosion resistance, abrasion resistance and decorativeness.

[0002]

2. Description of the Related Art Conventionally, high-quality natural materials such as buffalo, wood, crystal, and ivory have been widely used for seals for the purpose of using them for certification official seals. However, these have a problem that they have low hardness and are easily scratched or cracked on the printed surface and surface, and they are easily worn and cannot withstand long-term use. Also, due to the ban on ivory imports under the CITES, these natural materials are becoming difficult to obtain as rare resources.

Therefore, in recent years, a ceramic seal stamp has been used. Since these have heat resistance and high strength, they have excellent durability, but also have restrictions in the processing process. For example, JP-A-60-131861, 61-97164
In Japanese Unexamined Patent Publication No. 2-2, there is disclosed a method in which a ceramic molded body before firing is subjected to cutting work, stamped and then sintered.
In Japanese Patent No. 12257, there is disclosed a method in which a calcined body is printed and then main-baked. In addition, Japanese Patent Laid-Open No. 2-5
Japanese Patent No. 2550 discloses an example of engraving on a glass ceramic material.

[0004]

However, in the above-mentioned ceramics stamp, since the marking is performed before firing, the characters and shapes are likely to collapse, and there are problems such as deformation of the printed part after sintering and cracking. In some cases, the basic characteristics as a seal were not satisfied.

In response to the market demand for gold / silver seals, the above-mentioned ceramics seals can have an ivory color texture, but none of them exhibit gold / silver colors and are practically used. Therefore, an object of the present invention is to solve the above problems and provide a high-strength sintered alloy seal stamp that can perform precision printing processing to meet market demand, has excellent wear resistance and corrosion resistance, and exhibits gold and silver colors. To do.

[0006]

In view of the above, according to the present invention, a portion of at least a print surface of a stamp is made of TiN or Ti.
It is composed of a sintered alloy containing C as a main component and having an average crystal grain size of 3 μm or less and a porosity of 0.3 to 5%.

The stamp of the present invention can be obtained by firing a molded body containing TiN or TiC as a main component, and then stamping it on a predetermined surface. Generally, a sintered alloy containing Ti has high strength and an excellent color, but has a drawback of being inferior in chipping resistance. Therefore, in the present invention, in order to obtain a sharp printed surface, the material is improved and solved.

That is, in the gold-colored sintered alloy of the present invention, Ti is 55 to 75% by weight, the iron group metal and Group 6a element containing at least Cr are 3 to 29% by weight, and the balance is the balance. It is composed of a non-metal element, and the proportion of Cr in the metal elements other than Ti is 40% by weight or more. Here, the iron group metals include Ni and F
e, Co, and elements 6a of the periodic table are Cr and M
There are o and W, and nonmetallic elements include carbon (C) and nitrogen (N).

In the silver-colored sintered alloy, Ti is 55 in the total amount.
Wt% or more, Cr ₃ C ₂ is 1 to 20% by weight and Ni1~
It is to be 30% by weight.

Further, firing of these sintered alloys is performed by hot pressing, HIP or the like in addition to vacuum heating and firing, and a sintered body having a porosity of 0.3 to 5% can be obtained. The reason for limiting the porosity is that when the porosity is 0.3% or less, the paste of the red meat is remarkably reduced to have no use value as a printing material, and when the porosity is more than 5%, the strength of the main body is deteriorated. This is because there is a risk of damage due to, for example, dropping. Further, by setting the average crystal grain size to 3 μm or less, the stress acting on each grain is reduced and the occurrence of shedding is suppressed.

With these ingenuity, not only the color tone,
It was possible to obtain a good sintered alloy that was strong and did not cause chipping.

The marking method for the gold-colored sintered alloy is not limited to blasting, honing, water jet, laser beam, etc., and electrical discharge machining is also possible because it has electrical conductivity.

[0013]

According to the present invention, it is possible to obtain a stamp having high wear resistance and corrosion resistance and an excellent appearance. Also, various marking methods can be selected, and processing can be performed at low cost. Further, the printability is improved in combination with the sharp porosity and the appropriate porosity.

[0014]

Example 1 Particle size of 0.5 to 3.0 as Ti nitride and carbonitride
and TiN and TiCN of [mu] m, and Ni and Co of particle size 0.1~1.0μm as iron group metals, the particle size 1.0~10.0μm as periodic table 6a group element WC and Cr ₃ C
The respective powders of ₂ were weighed and mixed, and this was mixed and ground in an organic solvent such as acetone for about 68 hours, and then paraffin was added,
1.0 to 3.0c diameter at a pressure of 1.5 ton / cm ^2.
It was pressure-molded into a cylindrical column having a length of m and a length of about 5 cm. The obtained molded body was debindered at a predetermined temperature in a non-oxidizing atmosphere, and then vacuum fired at a predetermined temperature in a vacuum heating furnace for 10 hours to obtain a gold-colored sintered alloy. At this time, W and Cr were added as carbides as raw material powder, but they were melted in the binding metal as metal W or metal Cr in the process of firing or solid-solved in TiN or TiCN to form WC in the sintered alloy. And Cr ₂ C ₃ do not exist.
Further, TiN and TiCN are preferably present in the sintered alloy as crystal particles having a particle size of 10 μm or less.

The firing condition is that the degree of vacuum is 10 ^-1 to 10
Baking at a temperature of 1300 to 1800 ° C under reduced pressure or no pressure in an atmosphere of ^-4 torr or a non-oxidizing atmosphere. The firing time is usually 5 to 15 hours, depending on the size of the product.

After the outer periphery of this sintered body was ground, barrel finishing was carried out and the printed surface was finished by grinding, and this surface was stamped by the sand blast method to obtain the stamp of the present invention.

The color tone, corrosion resistance, and drop strength of the product thus obtained were measured, and the bending strength, Vickers hardness (Hv), and porosity were measured using test pieces. The bending strength was measured according to JIS R1601 three-point bending test method, the Vickers hardness was measured according to JIS Z2244 test method, and the porosity was measured according to Archimedes method. And for the corrosion resistance test, ISO (International Organization for Standardization)
The lower half of the mirror-polished sample was immersed in artificial sweat kept at a temperature of 40 ° C ± 2 ° C for 24H using artificial sweat (ph4.7) conforming to the standard as a corrosive liquid, and the sample polished surface after immersion It was done by observing the situation. Further, with respect to each sample, the chipping resistance and the redness at the time of printing were examined, and evaluated as very good (◯), good (Δ), and poor (x). The results are shown in Table 1.

[0018]

[Table 1]

As shown in Table 1, No. The sample No. 1 had a low porosity of 0.1%, and thus had poor printability. On the other hand, N
o. Samples Nos. 4 and 5 had a porosity of more than 5% and thus had a low bending strength and poor chipping resistance. In contrast,
No. A few of them had excellent printability and bending strength. Therefore, it is understood that the porosity of 0.3 to 5% is preferable.

The color tone of the polished surface of the sintered alloy according to the present invention was graceful and had a clear golden color, and had a remarkably excellent decorative effect. Furthermore, the result of the corrosion resistance test was very good, and neither discoloration nor corrosion was observed. Also,
When dropped from a height of 1 m onto concrete / P tile, there was no abnormality. Furthermore, the bending strength is 120 kg / m
m ² or more, 1200 kg / m in Vickers hardness
It showed extremely high strength and hardness at m ² or more.

[0021]

As described above, according to the present invention, at least the printing surface of the stamp has TiN or TiC as the main component, the average crystal grain size is 3 μm or less, and the porosity is 0.3 to 5.
% Composed of a sintered alloy, a clear and elegant gold / silver-colored mirror surface can be easily revealed, and excellent strength,
Since it has chipping resistance, it is possible to easily provide sharp edge processing, and it is possible to provide a seal stamp having excellent features such as good porcelain paste and no corrosion or flaws for a long period of time.

Claims (1)

Claims: 1. A seal stamp comprising a sintered alloy containing TiN or TiC as a main component and having an average crystal grain size of 3 μm or less and a porosity of 0.3 to 5%.