RU2079573C1 - Method of semitransparent rhodium films production - Google Patents

Abstract

FIELD: microelectronics, method is used to increase radioelectronic pieces wearability and to provide stable glittering of jewelry pieces. SUBSTANCE: surface of base is subjected to thermal vacuum treatment and rhodium-bearing compounds (acetyl acetonate, dicarbonylacetylacetonate or dodecarbonyl of tetrarhodium) vapors dissociation is carried out. After strengthening thermal treatment semitransparent rhodium film of 0.1-1.0 mcm thick, 9.1-9.4 of Mohs hardness scale, 13-17 kgf/cm adhesion and reflection factor of 91.2-97.3 %. EFFECT: increased radioelectronic pieces wearability and jewelry pieces glittering stability. 3 cl, 2 tbl

Description

 The invention relates to the manufacture of translucent metal rhodium films used to impart increased strength (wear resistance) and lasting gloss to jewelry made of gold and other precious materials, to increase the reflection coefficient of optical elements of mirrors of lasers, searchlights, emergency reflectors, reflectors and windshields of automobiles.

There is a galvanic method of deposition of rhodium films from solutions of rhodium sulfate Rh ₂ (SO ₄ ) ₃ • xH ₂ O, where x 4 15 [1] Compounds Rh (IV) are formed in the electrolyte, due to which the solution turns green, and a rhodium film is formed on the substrate. This method is unproductive, it requires the presence of an electric current conductor sublayer (in the case of metallization of dielectric substrates, for example, automobile windows, mirrors, etc.). It can not be used in industry because of the cumbersome implementation, the presence of environmentally harmful effluents and emissions, as well as because of the aggressive substances released during the mating process in relation to structural technological materials.

Closest to the proposed invention is a gas-phase method for producing rhodium films by decomposition of vapors of rhodium acetylacetonate Rh (C ₅ H ₇ O ₂ ) ₃ and rhodium dicarbonyl acetylacetonate Rh (C ₅ H ₇ O ₂ ) ₃ (CO) ₂ [2]

The sublimation of these compounds in this method is carried out at, respectively, 120 and 250 ^o C, the decomposition of the starting compounds at 600 and 700 ^o C, the residual pressure of their vapor 13 and 17 PA. This method is not suitable for producing rhodium films with a high reflection coefficient, since during the decomposition of these rhodium acetylacetonates, the surface of the rhodium films thus obtained is coated with rhodium whiskers (whisker single crystals) with a diameter of 0.1 to 0.3 μm and a height of 7 8 μm.

The present invention provides a method for producing translucent rhodium films with predetermined properties:
thickness 0.1 1 μm;
hardness H> 9 units Mohs;
adhesion to the substrate A> 10 kgf / mm ² ;
reflection coefficient R> 90% at a wavelength of light of 0.5 microns.

A method of obtaining a translucent rhodium film is carried out by preliminary thermal vacuum treatment of the substrate at a temperature of 90 - 100 ^o C and a residual pressure of (1 9) • 10 ^-3 mm RT. Art. within 20-30 minutes, the conversion of the initial crystals of rhodium acetylacetonate or dicarbonylacetylacetonate into a gaseous state at a temperature of 100 - 110 ^o C or 180 200 ^o C, respectively, in a special sublimator, controlled by the supply of vapor from the sublimator to a reactor in which thermal dissociation of vapor on the surface of the substrate at a substrate temperature for each compound, respectively, 510 530 and 550 560 ^o C at a residual pressure of (1 9) • 10 ^-1 mm RT. Art. and hardening heat treatment of the formed translucent rhodium film at 125 135 ^o C with a residual pressure in the reactor (1 9) • 10 ^-3 mm RT. Art. within 20 25 minutes

Dodecacarbonyltetrarodium with sublimation and dissociation temperatures of 200,200 and 550,560 ^° C, respectively, can also be used as starting material.

The reaction system is further equipped with an additional decomposer of the residues (traces) of rhodium carbonyl vapors, a carbon monoxide flame retardant, and a catalytically active filter pack for the final disposal of CO ₂ formed in quantities that are acceptable by the existing sanitary standards in our country and abroad. The invention does not have any environmentally harmful effluents and emissions.

 Implementation of the above method under other conditions is environmentally hazardous, non-technological and, most importantly, does not lead to the production of rhodium translucent films with a given thickness, hardness, adhesion and reflection coefficient.

 The method of producing translucent rhodium films (RDP) on the surface of small products (gold rings, mirrors, etc.) can be carried out in a metal cylindrical reactor, the walls of which are equipped with a cooled jacket, and rhodium-metallized products are preliminarily placed on a rotating table, heated with an infrared irradiator through sealed glass at the top of the reactor.

 When applying PRP to sufficiently large surfaces, such as automobile glass, a slot type reactor is used, in which the substrate is mounted on a uniformly moving holder. In this case, the PRP is formed at the moment of passage of the substrate, heated to the thermal decomposition temperature of the reaction zone, into which the vapors of the initial rhodium-containing compound are supplied.

 In both cases, the process of obtaining the PDP is as follows.

After loading or strengthening in the substrate holder, the reactor is sealed and a vacuum pump is turned on at room temperature, ensuring a vacuum up to (1 9) • 10 ^-3 mm Hg. Art. At the same time, the heating of the substrate is turned on.

 After creating a vacuum, the heating of the sublimator is switched on, which is carried out using a thermostat with a coolant circulating in its walls.

Before starting the process of applying a rhodium film to desorb gas molecules from the surface of the substrate, the latter undergoes thermal degassing in vacuum (1 9) • 10 ^-3 mm Hg. Art. at a temperature of 100 ^o C for 30 minutes

Upon reaching the set temperatures of the substrate and crystals of rhodium-containing substance in the sublimator using a bellows-type dispenser, pairs of the initial rhodium-containing substance are fed into the decomposition reactor. The vapor decomposition takes place in a vacuum (1 9) • 10 ^-1 mm Hg. Art. on the surface of substrates heated to the temperature of thermal dissociation of reaction vapors. In this case, a thin film of rhodium is formed, the quality of which depends on a specific technological regime.

The process ends with a stage of hardening heat treatment of the formed translucent rhodium film, which is carried out in vacuum (1 9) • 10 ^-3 mm Hg. Art. and at a temperature of 130 ^o C for 20 25 minutes

 The production modes and properties of the obtained translucent rhodium films are given in table. 1 and 2. In examples 1 to 3, rhodium acetylacetonate was used as a rhodium-containing substance, in examples 4 to 6, rhodium dicarbonyl acetylacetonate, and in examples 7 to 9 dodecacarbonyl tetrarodium. Examples 10 and 11 show, for comparison, the properties of aluminum and silver films.

 The thickness of the films was determined using calibration nets on a Philips scanning electron microscope. Hardness was determined using the pencil method on a reference scale in Mohs units used in jewelry. The adhesion to the substrate was determined by normal peeling on a P 0.5 instrument. The refractive index and light reflection coefficient were determined by the optical method with normal incidence of light on the surface of the PRP.

Claims (3)

1. A method for producing translucent rhodium films 0.1 to 1 μm thick, in which substrates are placed in the reaction chamber, the rhodium-containing compound is sublimated in vacuum and its subsequent thermal dissociation is carried out, characterized in that dodecacarbonyltetrarodium is used as the rhodium-containing compound, the substrate is preliminarily treated before sublimation at 90 100 ^o С and residual pressure (1 - 9) • 10 ^{- 3} mm Hg within 20 30 minutes, sublimation is carried out at 20 25 ^o C and a residual pressure (1 9) • 10 ^{- 1} mm Hg dissociation is carried out at 95 105 ^o With and a residual pressure (1
9) • 10 ^{- 1} mmHg. Art. then conduct hardening heat treatment of the rhodium film at 125 135 ^o C and a residual pressure of (1-9) • 10 ^-3 mm RT.article within 20 25 minutes 2. A method for producing translucent rhodium films 0.1 to 1 μm thick, in which substrates are placed in the reaction chamber, the rhodium-containing compound is sublimated in vacuum and its subsequent thermal dissociation is carried out, characterized in that rhodium dicarbonylacetylacetonate is used as the rhodium-containing compound and the substrate is heat treated before sublimation. at 90 100 ^o С and residual pressure (1 9) • 10 ^{- 3} mm Hg within 20 30 minutes, sublimation is carried out at a temperature of 180-200 ^o C and a residual pressure (1 9) • 10 ^{- 1} mm Hg dissociation is carried out at 550 560 ^o With and a residual pressure (1 9) • 10 ^{- 1} mm RT.article. then conduct hardening heat treatment of the rhodium film at 125 135 ^o C and a residual pressure (1 - 9) • 10 ^{- 3} mm Hg within 20 25 minutes 3. A method for producing translucent rhodium films 0.1 to 1 μm thick, in which substrates are placed in the reaction chamber, the rhodium-containing compound is sublimated in vacuum and its subsequent thermal dissociation is carried out, characterized in that rhodium acetylacetonate is used as the rhodium-containing compound, and the substrate is heat treated before sublimation. at 90 - 100 ^o С and residual pressure (1-9) • 10 ^{- 3} mm Hg within 20 30 minutes, sublimation is carried out at 100 110 ^o C and a residual pressure (1 9) • 10 ^{- 1} mm Hg dissociation is carried out at a substrate temperature of 510 530 ^o C and a residual pressure (1 9) • 10 ^{- 1} mm RT.article. then conduct hardening heat treatment of the rhodium film at 125 135 ^o C and a residual pressure (1 - 9) • 10 ^{- 3} mm Hg within 20 25 minutes

Images