JPH02217492A - External parts for timepiece - Google Patents

Abstract

PURPOSE:To obtain ornamental parts having superior corrosion and wear resistances, adhesion and metallic luster by forming an underlayer of a specified noble metal on the surface of each of ornamental parts made of stainless steel, etc., further forming a black Sn-Ni-S layer on the underlayer and then forming a passivated coating film by chromating. CONSTITUTION:Ornamental parts such as external parts for a timepiece are made of a Cu alloy 1 so plated with Cu or Ni in a single or laminated layer as to improve the corrosion resistance or corrosion resistant stainless steel 1 such as SUS 304. An underlayer 2 of at least one kind of noble metal having high corrosion resistance such as Pd, Pd alloy, Rh, Au or Au alloy is formed by plating on the surface of each of the parts and a black sulfide layer 3 consisting of 30-50% Ni, 0.5-1.5% S and the balance Sn and having inferior corrosion resistance is formed on the underlayer 2 in 0.5-3mum thickness. A passivated coating film 4 is then formed by chromating. Ornamental parts having superior corrosion and wear resistances and fine black appearance such as external parts for a timepiece and spectacle frames are produced.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention provides a ternary alloy plating of Sn-Ni-3.
The present invention relates to an exterior part for a watch whose surface has a blackish metallic luster.

[Summary of the Invention] The present invention provides exterior parts for watches with unprecedented wear resistance, corrosion resistance, and adhesion by coating a Sn-Ni-8 ternary alloy plating with a passivation film by chromate treatment. [Prior art] A conventional surface treatment technology for decorative parts such as mobile watches and eyeglass frames that has a black tone. as black R
h, black Ru, black Ni, S according to JP-A-63-14888
n-Ni and Sn-Ni according to JP-A-59-23895
Wet plating of -Cu, etc., alumite, thermal spraying and ion blating, and dry plating such as CVD are generally known.

[Problems to be Solved by the Invention] However, in the prior art described above, black Rh, black Ru, black Ni
and Sn-Ni-C shown in JP-A-59-23895
In wet plating of U, the plating thickness is at most 0.5 to 1.
Since the hardness of the coating is limited to about 100 mL and the hardness of the coating is low, the abrasion resistance required for exterior parts for watches is extremely poor and cannot be applied. Also, Sn-
Since Ni plating can be applied several micrometers thick, its abrasion resistance is satisfactory, but since one color tone is very light gray, it is insufficient as a black surface treatment and cannot be applied.

The alumite coating has corrosion resistance and scratch resistance.

Further, the thermal spraying method has problems in that it has poor corrosion resistance and a honed appearance, which limits its use as exterior parts for watches.

In addition, T by dry ion blating and CVD method.
Compounds such as i, C10, and N have high hardness and wear resistance, which is sufficient for use as exterior parts for watches, and they also have excellent scratch resistance and adhesion, but the manufacturing method requires expensive equipment and equipment, and production is difficult. Since the capacity is also lower than that of wet plating, the processing cost is high, making it difficult to apply it to ultra-low-priced products. The present invention is intended to solve these problems, and its purpose is to improve wear resistance and adhesion by passivating the Sn-Ni-5 layer created by wet plating. , a black watch exterior that provides watch exterior parts with excellent corrosion resistance and high decorative value, and has a coating structure that is processed using an existing metal coating line, making the manufacturing cost much lower than the conventional dry method. It is located at a place that provides parts.

(Means for Solving the Problems) The watch exterior parts of the present invention include (1) Pd, Pd alloy, Rh, Au as a base layer on the surface of the watch exterior parts made of copper alloy or stainless steel;
, at least one type of Au alloy is formed, and immediately above the base layer, Ni: 30 to 50%, S: 0 at a weight ratio of 1.
．． 5 to 1.5%, the balance Sn and unavoidable impurities to form a black Sn-Ni-S layer,
A passivation film is formed on the i-5 layer by chromate treatment, and (2) the thickness of the Sn-Ni-5 layer is 0.5 μm to 3 μm.
When the passivation film surface on the Sn-Ni-S is specified in JIS 28105-2068 (CI E
l 976) L”, a”, b” in color space
%a*, b* are 40%≦L1≦60%, -1≦, respectively
80≦4. It is characterized by having a black tone that satisfies the relationship: -15b''≦4.

[Function 1] According to the above structure of the present invention, first, regardless of whether the material is stainless steel or copper alloy, a highly corrosion-resistant Pd, Pd alloy, Rh, Au, or Au alloy is applied directly under the black Sn-Ni-8 layer. By forming the noble metal layer, corrosion resistance quality is ensured before forming the Sn-Ni-3 layer, which has no effect on improving corrosion resistance because the coating itself is a sulfide compound. When the material is stainless steel, which itself has good corrosion resistance, the purpose of the noble metal plating is to improve the adhesion of the Sn--Ni-5 layer in addition to ensuring the above-mentioned corrosion resistance. If the material itself is a copper alloy with poor corrosion resistance, it is necessary to improve the corrosion resistance to some extent by applying a single layer or a stack of Cu plating or Ni plating before forming the base layer of the Pd, Pd alloy, Au, or Au alloy. In particular, copper alloy materials made using the casting method have many cavities and pinholes on the surface, which is the main cause of poor corrosion resistance in practical mobile phones.

First, it is necessary to apply Cu plating, which has a high leveling effect, to the surface. Furthermore, Cu plating and Ni plating have extremely high adhesion to the copper alloy material, and as the first layer plating on the copper alloy, the adhesion is completely maintained. The Sn-Ni
-5 The effect of the S component in the ternary alloy increases the coating hardness,
It also has the function of making the color tone darker. Since the coating hardness is as high as Hv300 to 400, the coating thickness can be reduced to 0.5% m. If the thickness is less than 0.065 μm, there will be a problem in terms of wear resistance. Also, if it exceeds 3 μm, the internal stress will be high (and the adhesion of the film will decrease, so the film thickness should be 0.5 μm to 3L).
The thickness of the 8th order Sn-Ni-S coating limited to Lm is 0
．． When the thickness is 5%m to 3um, the black tone as an exterior part for a watch is 40%≦L1≦60%, -1≦a 11≦
4. It has a novel black tone that has never existed before in the range of -1≦b0≦4.

If Lo is less than 40%, the appearance will be too dark with no gloss, and if it is more than 65%, the shine will be too strong and bright, so the range of L0 is limited to 40%≦L0≦60%, and more preferably 45%≦L0. ≦55% is desirable, and am
, if bo is less than 11, the greenish and bluish tinges will be too strong, and ae
, If bo exceeds 4, redness and yellowness will become too strong, so a
.

b@ is 1≦80≦4, respectively. -1≦b0≦4, and preferably both am and be are O~2,
In the Sn-Ni = S ternary alloy, the Ni component greatly affects L* and the S component greatly affects a" and bo. In other words, when Nf% increases, Lo becomes low, and when Ni% decreases, Lo becomes high (
If 8% increases, am and bo will decrease, and 8% will increase.
When decreases, ae and bo increase. Due to these color tone constraints, the composition of the Sn-Ni-s = original alloy is 730% to 50% Ni, 0.5% to 1.5% S, and the balance is Sn.
and become unavoidable impurities. Although the above configuration ensures the black appearance, adhesion, and wear-resistant quality as an exterior part for a watch, the Sn-Ni-S alloy layer has little effect on improving corrosion resistance, so the corrosion resistance of the underlying metal deteriorates. and S
There are concerns about the corrosion resistance of the watch case as a whole due to sulfurization of the components. Therefore, in the present invention, the Sn-Ni-8
By forming a passivation film on the layer through chromate treatment, the food-resistant properties of the product are completely ensured. The chromate treatment is a colorless and transparent inorganic coating, and since it is several hundred thick, it does not change the color tone and appearance of the Sn-Ni-8 alloy layer.The present invention will be described below based on examples.

[Example] A 0-order Sn-Ni-S ternary alloy was plated on a watch case that had been appropriately subplated with stainless steel and copper alloy materials using the plating liquid composition and plating conditions shown in Table 1. - on the Ni-S layer.

Potassium dichromate 15g/I2 sulfuric acid
1g/2 dibasic potassium phosphate
200 people were coated with a transparent Lomate film under conditions of 15 g/β current density 0.5 A/dm for 2 hours and 30 seconds and a liquid temperature of 30°C.

A watch case coated with the above method was used to make a finished mobile watch case, and then tested and evaluated for color tone, corrosion resistance, abrasion resistance, and adhesion. The results are shown in Table 1.

The subplating configuration and thickness in the Examples and Comparative Examples are as shown in Table 2 below.

Evaluation criteria for the evaluation characteristics in Table 2 and Moe's Table 1 are shown in Table 3.

Next, the method for confirming each characteristic will be described below.

The color tone of each coating surface is JIS Z 8105-201
JIS Z8105 using standard light C specified in 4.
Find the spectral reflectance defined by -101.3 and convert this value into (
CIE1976) L", a"b' color space and quantification.

Further, the color tone was determined visually, and the film thickness was determined by shadowing the film, and the step formed at that time was measured using a micro-roughness meter manufactured by Kosaka Institute. The hardness was measured using a micro Vickers hardness tester under a load of 10 gr. In addition, wear resistance was determined by applying a 500g load to the watch case and abrading it back and forth 30,000 times with a 10cm stroke, and checking the degree of wear of the coating on the side of the watch case. For adhesion, compressive load was applied to the watch case from both ends in a vise so that the temperature at the bent portion was 90°C or higher, and the degree of peeling of the coating at the bent portion was examined. ii For 4-feeding food, add 40% of the finished watch case to artificial sweat and artificial seawater (3% NaCf2).
The specimens were immersed for 24 and a half minutes in a warm and humid atmosphere of 90% °C, and the occurrence of corrosion and discoloration was examined.

In the above examples, as shown in Samples 1 and 2 of the present invention, the stainless steel and brass materials were suitably subplated.
The finished mobile watch case has a Sn-Ni-5 ternary alloy plating applied to the surface and a passivation film created by chromate treatment, and has a black metallic luster with an unprecedented sense of luxury. In addition, no corrosion was observed in the corrosion resistance tests using artificial sweat and artificial seawater, and even in the adhesion test by bending, sufficient adhesion was obtained with no peeling of the produced film. Moreover, the surface hardness was Hv300-400, and no exposure of the base material was observed in the abrasion resistance test. However, as shown in Inventions 2 and 4, if the Ni% and 5% are small (when the Lo is high and the color tone becomes sparkling, the 5%
The redness and yellowness increase due to the influence of %. When this tendency becomes remarkable, Ll is 62% in N12S% shown in Comparative Example 3.
The sparkle becomes large, and the S0.4% shown in Comparative Example 5 has a strong red-yellow tinge, resulting in a color tone that cannot be used as a decorative item.
%, a°≦4. It is limited to b°≦4. Similarly, present invention 3
and Ni% as shown in 5.

When 5% increases, the color tone becomes low Lo (darkened color and 5%).
The greenish and bluish tinges increase due to the influence of %.

As a notable example of this, when the Ni% is too high as shown in Comparative Example 4, and when the Ni% is too high as shown in Comparative Example 6, it becomes unusable as a decorative item. S≦1.5%, and a0≧-1,
It is limited to 6≧−1. From the above, the conditions that can be applied to the black tone of exterior parts for watches are: Ni: 30% to 50%
S: 05% to 1.5%, remainder Sn, and L':
40-60%, a" knee 1-4, b@: 1-4. The thickness of the Sn-Ni-3 layer is thinner than 0.5u shown in Invention 6 as shown in Comparative Example 1. like 06
At 4 μm, the wear resistance decreases, and conversely, when the thickness increases beyond 3.0 μm shown in Invention 7, it becomes 3.2 μm as shown in Comparative Example 2.
When the thickness is .mu.m, the internal stress of the broken pattern increases, resulting in poor adhesion. From the above, from the viewpoint of adhesion and wear resistance, the thickness of the Sn-Ni-3 ternary alloy is limited to 0.5 μm to 3.0 μm, and the effects of chromate treatment are described in 1 to 8 of the present invention. As is clear from the difference in the results of Comparative Examples 2.3.6 without chromate treatment, a large effect of improving corrosion resistance was confirmed.

[Effect of the invention] As described above (black Ni, black Ru, black Rh and Sn-N
Wet plating such as i, dry plating such as ion blating/CVD, or conventional methods such as alumite and thermal spraying,
There were problems in terms of wear resistance, black appearance, corrosion resistance, and manufacturing cost, but the present invention has improved the appearance by layering a passivated pus by chromate treatment on the Sn-Ni-S ternary alloy plating. It is now possible to provide a black surface treatment that exhibits a black tone with an unprecedented sense of luxury and satisfies the basic qualities of adhesion, corrosion resistance, and abrasion resistance as an exterior part for a watch at a lower cost than before. It has become possible. It can be applied not only to mobile watch cases, but also to general decorative parts such as watch bands, eyeglass frames, lighters, decorative bands, buckles, and tie bins.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a watch case made using Sample 1 of the present invention. 5US304 material 24° Au plating layer Sn-Ni-S plating layer Passivation coating layer Applicant Seiko Epson Corporation

Claims (2)

[Claims] (1) At least one of Pd, Pd alloy, Rh, Au, and Au alloy is formed as a base layer on the surface of a watch exterior part made of a copper alloy with a single layer or a stack of Cu or Ni, or a stainless steel base, and Immediately on top of the base layer, Sn exhibiting a black color consisting of Ni: 30 to 50%, S: 0.5 to 1.5%, and the balance Sn and unavoidable impurities.
- An exterior part for a watch, characterized in that a Ni-S layer is formed, and a passivation film is formed on the Sn-Ni-S layer by chromate treatment. (2) The thickness of the Sn-Ni-S layer is 0.5 μm to 3 μm
When the passivation film surface on the Sn-Ni-S is specified in JIS Z8105-2068 (CIE197
6) L^*, a^*, b^* in color space L^*, a
^*, b^* are respectively 40%≦L^*≦60%, -1
2. The exterior part for a timepiece according to claim 1, having a black tone satisfying the following relationships: ≦a^*≦4, -1≦b^*≦4.