A New Method of Thin Layer Coatings Deposition of Noble Metals
The original, technologically-convenient method of electroless coating deposition of precious metals (gold, silver, platinum, palladium and ruthenium) and some other metals (copper, nickel, bismuth, mercury, antimony) on metal substrates (copper, nickel and its alloys, brass, bronze, some sorts of steels) is developed.
The noble metal coatings are widely used in modern industry, mostly in microelectronics (printed circuits, wiring, waveguides) to give the articles the necessary functional properties, namely a low contact resistance and a stability to the environment action. In modern instrument-making the finish coatings of gold or other noble metals are widely used and in the recent past there has been a clear tendency to a decrease of the coatings thickness.
The method allows us to achieve high-density, nonporous, fine-crystalline coatings with a high adhesion to the substrates (up to 80-100 kg/cm 2 ). The coating thickness can be varied from 0,01 to 2 μm. The reactions times- 2-20 minutes. A visual appearance of the coating (bright or matt) depends on the initial roughness of the substrates surface.
A serious advantage of an offered method is the reception of the coatings from metal alloys, for example, Ag-Au, Ag-Pd, Ag-Bi, Ag-Ni, Ag-Sb, Pd-Au, Pd-Ru, Pd-Ni, Pd-Co, and also intermetallic compounds, for example Pd 3 Pb. It allows the supply of functional properties of thin metal coatings (for example, stability to deterioration, catalytic properties, etc), as the alloys have, as a rule, properties, interesting to practice.
New methods are intensively developed for the high quality thin layer coatings fabrication. Such coatings with a layer thickness of 1 μm and lower than 1 μm must have the functional characteristics identical to the properties of the thicker coatings.
Applications
· Microelectronics (printed circuit boards)
· Electrical radio engineering (electric wires, electric contacts, waveguides)
· Illuminating engineering (light reflectors, mirrors of optical lasers)
· Catalysis (metal catalytic systems)
· Decorative gold and silver plating
Our method has the following advantages compared with the traditional ones:
• Environmentally-safe caused by the absence of cyanides and other toxic compounds,
• increased productivity,
• versatility of the method allowing one to obtain various coatings using the similar solutions,
• simple composition of the solution (1-2 components),
• wide range of used concentrations (1-20 g/l),
• high stability of solutions allowing one to keep them during a number of years without losing their activity.
Sertification of the technology
The technology proposed got a certificate of a Golden medal of the International exhibition of inventions and new technologies Eureka (Brussels, 1997) and a Golden medal of 5-Internation forum High Technologies of 21 century( Ìîñêâà , 2004).
The Authors
Galina K. Strukova , Dr. techn. sci., senior researcher at the Institute of Solid State Physics of Russian Academy of Sciences, since 1968. She graduated from the Kazan State University (physical faculty) and has 40 publications and 5 inventions to her credit. This is for work in the semiconductors field where she was awarded the honorary sign USSR inventor. Scientific interests field: semiconductors physics and chemistry, high temperature superconductors, metallic coatings.
Gennadi V. Strukov , Dr. techn. sc., senior researcher at the Institute of Solid State Physics of Russian Academy of Sciences. In 1964 he graduated from the Kazan Chemical-technological Institute. He has more than 50 publications and 14 inventions to his name. Scientific interests fields: technical chemistry and technology, chemical sources of current, metal coatings, metallic complex chemistry.
Victor V. Kedrov , Prof. chem. sc., l eading research scientist of the Institute of Solid State Physics of Russian Academy of Sciences. In 1964 he graduated from the Saratov State University (physical department). He has 62 publications and 20 inventions connected with metal hydrides chemistry and physics. For his achievements in this field he was awarded the Diploma and Medal of USSR State Premium in 1984. Scientific interest fields: chemistry and physics of metal hydrides, chemical sources of current, metal coatings, metallic complex chemistry.