Iron oxide pigments: characteristics, application

Manufacturers are forced to constantly improve the competitiveness of their products because of the current market saturation with imported and Russian materials. Therefore, at the same time with the quality properties to the products, decorative requirements are also imposed.

Definition

Iron oxide pigments are an inorganic type of substance consisting of hydrates of oxides and oxides of different valence levels. By the method of production, they are divided into natural and synthetic. In comparison with natural, the latter are used much more often. This is substantiated by the large content of coloring substances in pigments of synthetic type and low cost. Iron oxides have an extensive color variety: from black and blue to yellow and green tones.

Iron oxide pigments: characteristics

Among the properties of pigments is worth noting the following:

• Hiding power reflects the flow rate to cover a unit of a plane. Than this indicator is lower, the less substance will be spent.
• Dispersion. With a decrease in the fineness of grinding, the coloring abilities increase.
• Intensity is the ability to transmit your shade when mixed with other substances of a certain saturation. The intensity is displayed as a percentage of the standard output by the manufacturer.
• Lightfastness is a resistance to photochemical effects.
• Constancy. Regardless of the party, the hue should not change the intensity.
• Thermal resistance is the ability to maintain color within a specified temperature range.
• Presence of water-soluble additives.
• Acidity of the aqueous suspension. It should not exceed the optimum pH value of 7. Due to the fact that the cement differs alkaline reaction medium, due to the use of a substance with low acidity, the mixture will be completely discolored.

Painting of concrete

For the painting of products made of concrete, iron oxide pigments with a low spreading power and a distinctive coloring characteristic have been used for a long time. They are not affected by alkali, certain types of acids, salt, sunlight. Due to this, pigments became so common when painting cement hydration objects.

In stores are presented iron-oxide pigments of foreign and Russian origin. To give concrete a shade, depending on the region of manufacture, the introduction of substances from 3 to 15% of the total weight is required. It should be borne in mind that the pigments are more dispersed than Portland cement, so if the concentration is exceeded, there will be a sharp increase in the demand for the mixture in the water, which will subsequently lead to a significant decrease in strength when pouring and increasing the porosity.

Pigment ferrioxide: application

The technical data of the equipment affect the effectiveness of the use of colorants. With a small proportion of the pigment in the base mass, to obtain complete dissolution, equipment that has a high agitation speed is necessary. The pigment changes the color of only the cement binder from the entire concrete mix, so the same amount of pigment will intensively color the mixture with a significant cement content than the mass with a small amount.

Two or more pigments are used to create shades of cement, different from the tones of individual colorants. The use of a combined type of coloration requires mixing before application to the material until the desired shade is obtained. This will take more time than painting one pigment.

Basic dyes

Pigment yellow iron oxide has resistance to weathering, light fastness, thermal stability, excellent coloring characteristics. It is used in the manufacture of products made of concrete for various purposes, tiles, plasters, roofing tiles, many types of primers. Czech and Chinese dyes have similar consumer properties, while the latter are in the lower price segment. Such pigments, created on the basis of ocher, differ granular stable composition.

Pigment black iron oxide is a persistent chemical substance that has found its application in the manufacture of colored cement goods, fillers, paints. The dry type of the dye differs in its hiding characteristics and depth of tone, while it does not burn out and is not subject to temperature influence, an elevated level of alkali. Finished products receive agate resistant tone.

Red pigment is produced mainly by Czech and Ukrainian manufacturers in the form of a powdery inorganic compound. The base used ensures durability and color saturation.

White dye is not soluble in organic acids and water, nor is it toxic to humans. It is realized in most cases in bags of 25 kg.

What determines the degree of dyeing

The color of the finished products is influenced by the shade of the cement itself. Gray tone has the ability to dim the brightness, so when working with standard portland cement it is difficult to get juicy colors. The best option is white cement, also used to create blue and green shades.

Each type of material has its own gray color. Different manufacturing plants also produce cement of one type, which differs among themselves. There are such differences on the colored concrete, while the light material is more sensitive compared to concrete having dark iron-oxide pigments. So, for the same batch of products from this material, the same cement from the same producer should be used.

The tone of the filler can also affect the final shade of light products. Here the rule of uniform composition in the production of one batch of goods is relevant. There is a significant decrease in this effect in black and blue concrete. The color is not heavily affected by the density of the material, but with poor compaction of porous concrete, there is a possibility of occurrence of high temperatures during storage and use. Their appearance worsens the appearance, they do not influence the pigments, but the solids are much more noticeable on the painted surface than on the natural surface.

Ratio of components

In the preparation of cementitious color mixture should be taken into account the dosage of the substance by weight, since the pigments iron-oxide for concrete have different densities. It is also important to observe an equal period of mixing, this will allow the mixture to be evenly colored.

Different color curing conditions lead to color changes. There may be a different shade due to the rapid evaporation of moisture and condensation on the plane, there is also the possibility of a light raid. To obtain the desired result, it is necessary to observe the proportions of water for the dilution of concrete and the temperature regime. There is one characteristic pattern: needle crystals have a high pour point. Small crystals enhance the scattering of light, which makes the color look lighter than the tone of similar concrete frozen at low temperature.

Types of pigments

Iron-oxide pigments are usually divided into weak, with a total critical concentration of 25%, and conditionally strong concentrations of 10%. If more than 10% of the colorant is required to produce a certain shade from the volume of the material, it is desirable to use a smaller proportion of the strong pigment. This is due to the fact that a large proportion degrades the strength characteristics due to increased water absorption.

To create pastel concrete products it is difficult to establish small proportions, so it becomes rational to use a full portion of a conventionally weak coloring material.

Manufacturers

Among the main producers are German, Czech and Chinese factories. From the point of view of the ratio of price and quality, today, Chinese pigments are more attractive. The most widespread among the Czechs were red and brown tones. In terms of quality, German coloring matters occupy the first place, but because of their high cost, their use for paving is unprofitable.

Iron oxide pigments (Russia) have low price and satisfactory properties, due to what they make worthy competition with imported ones.