JPS6350491A - Method for plating amorphous palladium - Google Patents

Abstract

PURPOSE:To form an amorphous Pd film having superior characteristics when Pd plating is carried out with a plating soln. contg. a soluble Pd salt, by adding As to the plating soln. CONSTITUTION:A Pd plating bath contg. 0.01mol/l sodium arsenite is used at ordinary temp. or about 50 deg.C and electric current is supplied at 5mA/cm<2> current density to form an amorphous Pd film on a metallic material to be plated as the cathode. An amorphous Pd plated product for ornamentation having superior smoothness and fine appearance as well as superior corrosion resistance is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to an amorphous palladium plating method in which an amorphous palladium plating film is deposited by wet electrolytic plating at room temperature or at a heated temperature.

2. Description of the Related Art Conventional palladium plating films are generally crystalline palladium plating films, but a method of obtaining an amorphous palladium plating film by wet electrolytic plating has also been invented.

Problems to be Solved by the Invention However, the above-mentioned crystalline palladium plating film lacks surface smoothness due to its crystal structure and also has problems in corrosion resistance.

In addition, the method of obtaining an amorphous palladium plating film by wet electrolytic plating has a low electrodeposition efficiency because the electrolytic plating is performed at a low temperature of -3000°C, and the film contains a large amount of hydrogen and the temperature rises to room temperature. Over time, crystallization of the coating occurs, causing problems in terms of work efficiency, work management, and quality.

Traditionally, single metals and alloys with amorphous structures have attracted attention as new materials because they have superior physical and chemical properties compared to those with crystalline structures, and are used in liquid quenching and sputtering methods. Amorphous metal coatings are obtained by methods such as , vapor deposition, etc., and it is also possible to obtain amorphous palladium coatings by these methods, but the processing methods are not easy and are expensive. There is a problem.

Means for Solving the Problems This invention has been made in view of the above problems, and it is possible to form an amorphous palladium plating film by electrolytic plating at room temperature or at a temperature using a plating bath containing arsenic. It is characterized by being obtained by.

As the arsenic, sodium arsenite or the like is used.

Effect This invention is based on the above means, and as arsenic,
Neutral F2DT shown below using sodium arsenite
A palladium plating bath using electrolyte A was prepared.

EDTA-2N, 2 0.3 mat/1
NIZ2SO80,4mol/L Na2AsO2o,o 1mO4/l Pd (en) 22+5oln O,1mot
/1 The reaction mechanism of palladium deposited from the above plating bath was proposed using the following equation.

tl1 formula % formula % (2) formula As02soln +2H20-As ads -1
-40H- The arsenic adsorbed ion represented by the above formula (1) or (21) is involved in the precipitation of palladium as an active site (Al), and the arsenic adsorbed ion shown in the above formula (1) or (21) is involved in the precipitation of palladium from the ethylenediamine palladium tUt complex containing sodium arsenite. Precipitation can be considered as shown in the following equations (3) to (5).

(3) Formula % Formula % (4) Formula Pd”ads −Al2 e: Pd ads
-A (5) When plating was performed using formula %, a smooth amorphous radium plating film was deposited.

Example 2゜Pulse electrolytic plating bath temperature: 25℃ When pulse electrolysis was performed using the above three conditions (bl, (C1, +(11), a smooth amorphous palladium plating film could be obtained, and the hydrogen storage capacity was has also decreased significantly.

Plating (a-d) obtained from Examples 1 and 2 above,
Crystalline palladium plating (8
1 was plated on 5US304 material to a thickness of 2μ, and OA!
When a 3S test was conducted, the platings (a to d) obtained test results showing good corrosion resistance as shown below compared to the plating (el).

The drawings are X-ray diffraction diagrams of each of the above-mentioned platings, and the amorphous palladium plating films ta+, (1)), (C1, +(11) are each - obtained in Examples 1 and 2 above. Compared to the crystalline palladium plating film +81 obtained from a general commercially available plating bath, the peak of the high index plane on the (200) chamfer disappears, the (111) plane becomes broad, and the (a -d) The film has an amorphous structure.

As described in detail of the invention, amorphous palladium, plated film,
It can be easily obtained by stirring or heating at room temperature, provides a smooth appearance that is good for decorative purposes, and provides a plating film with excellent corrosion resistance, making it an excellent palladium plating film for ornaments, etc. It has the following effects.

[Brief explanation of the drawing]

The drawing is an X-ray diffraction diagram of the plating film. Patent applicant: Tonan Metal Industry Co., Ltd. ike】name

Claims (1)

[Claims] An amorphous palladium plating method, characterized in that the amorphous palladium plating film is obtained by electrolytic plating at room temperature or with heating using a plating bath containing arsenic.