In the equipment and in life various ways of drawing coverings are widely applied. One of the most widespread technologies of this plan – chemical metal coating. Otherwise it is called still decorative chromium plating, chemical chromium plating or a mirror covering. The main advantage of this technology – safety in terms of ecology.
Scopes of chemical metal coating
Chemical metal coating performs two main functions: protection of a surface against wear and decorative registration of a product. This technology is widely applied both on production, and in the conditions of house workshops. The way is suitable for processing of any surfaces with rigid structure.
Stages of chemical metal coating
Distinguish several stages of process of decorative chromium plating:
- putting soil;
- processing of a surface chemical reagents;
- putting protective varnish.
The first stage of chemical metal coating consists in drawing on a surface of a product of a layer of special binding soil. The kraskoraspylitel is for this purpose used.
Soil is applied with several layers, the smooth vitreous surface having glossy properties is not formed yet. One of primer functions – ensuring adhesion of a layer of the applied metal, that is its coupling with a surface. The dried soil becomes active in relation to a metal coating layer. It provides the sufficient speed of sedimentation, excellent coupling and characteristic gloss of a metal covering.
When binding soil dries, by means of installation for metal coating apply chemical reagents on a surface. Several methods of transferring of reagents on the processed surface are known. All of them have the features, merits and demerits. The choice of a concrete way is defined by the nature of a surface of a product.
The surface of a product is activated by means of drawing the activator on it. The activator is defined by operational properties of a surface. The type of future surface is specified usually on the label of a reactant (for example, copper, chrome, gold).
Then the product is washed the demineralized or distilled water. Now it is necessary to spray reagents – the modifier and reducers.
Between a covering and a surface of a product during metal coating the reliable and stable relation which is capable to remain very long is formed.
As a result of chemical reaction the mirror metal covering turns out. Allows to protect a smooth surface from mechanical wear and tarnishing putting special varnish. It is put with several layers. If to add the painting pigment to varnish, the surface of a product can give various shades. In such a way it is possible to receive imitation of various metals and their alloys (gold, bronze, copper, chrome).
It is convenient to apply on the metallized surface protective varnish by means of a special airbrush. Varnish has to have the good getting and moistening ability. Excellent performance data varnish with additives in the form of light-transmitting pigments possesses: such structure gives to a surface a type of precious metals and rare alloys.
Types of chemical metal coating
The essence of a method consists in drawing on a surface of very thin layer of metal. Similar processing is suitable for metal, wood, glass, plastic and some other materials.
The most popular types of chemical metal coating:
- chromium plating;
- galvanizing;
- alitizing (drawing layer of aluminum).
Types of a method of chemical metal coating:
- galvanic method;
- arc method;
- gas-plasma dusting;
- diffusion method;
- hot method;
Chemical metal coating: features of technology
The main objective of chemical metal coating consists in improvement of decorative properties of a product. This way of processing allows to hide also possible defects of a surface (microcracks, a small time, etc.). Sometimes such method is applied to complete recovery of the destroyed surfaces.
Use of chemical metal coating gives the chance to improve the following characteristics of a product:
- wear resistance;
- corrosion stability:
- hardness;
- decorative properties.
When performing chemical metal coating it is important to provide the best conditions for the course of oxidation-reduction reactions. If such conditions are created, from composition of initial substance there will be a departure of atoms to the largest potential. To control this process visually can be difficult, however the result will be noticeable at once: color of the processed surface will change.
The essence of technology consists in processing of a surface special reagents which enter certain reactions among themselves. Formation on a surface of a thin layer of metal becomes result of chemical interaction. Under certain conditions it is possible to achieve not only obtaining right color, but also to execute smooth transitions between different flowers of a surface.
The mirror coverings received by method of chemical metal coating on appearance practically differ in nothing from the similar metal coverings received by a sedimentation method. Such mirror coverings do not grow dull and are not exposed to corrosion even at long operation in adverse conditions.
Introduction to soil and varnish of the plasticizing additives gives to a finished product good elasticity. It allows to apply technology of metal coating to those products which at operation are subject to mechanical deformations.
Equipment and materials for chemical metal coating
This technology can be used not only on production or in research laboratory, but even in the conditions of a house workshop. But without use of the special equipment it will be possible to metallize only surfaces of the small size, simple in a form.
A set of reactants for chemical metal coating includes the activator and reducer. Also primer and varnish is required. At the same time for finishing finishing of a surface it is necessary to choose paints and varnishes which have the increased wear resistance and hardness. Does not prevent to have also near at hand special smyvochny solutions: they are applied to removal of a fresh covering if it for some reason does not meet the necessary requirements.
The reactants applied in the course of chemical metal coating do not contain carcinogens, heavy metals and caustic substances and also explosive components. Waste of this technology is without effort transferred to absolutely harmless connections and utilized.
The simplest installation for chemical metal coating consists of the blowtorch and the enameled capacity.
Algorithm of performance of chemical metal coating:
- to clean a surface from pollution;
- to degrease a product;
- to wash a product with water;
- to fix a product on an electric wire;
- to lower a product for an hour in the container with electrolyte;
- to take a product from solution, to dry up and cool;
- to polish a surface.
When carrying out chromium plating in house conditions it is important to prepare qualitatively a product, having removed all pollution. Between future metal layer and the basis there should be no layers. Otherwise performance data of a product will be significantly lower, the term of operation of a product will decrease. It is the best of all to degrease a surface alkaline solution, and then to wash carefully with clear water. If on a product there are sites which do not need to be metallized, they should be processed lead. This metal does not react to effect of electrolytic solution.