The Influence of Surface Quality of Coatings on Their Deformation Properties

Results of researches on influence of a roughness on deformation properties of coverings are resulted. The model of durability is offered at a stretching depending on a roughness of a surface of coverings


Introduction
Durability coatings, among other factors depends on the quality of appearance [1,2,3].The probability of destruction of protective -decorative coverings depending on presence of defects on their surface can be determined on expression: S e P    1 (1) where  -concentration of defects; S -the area of a surface.
Apparently from the formula (1), the probability of destruction of coverings grows with increase in concentration of defects.

The methodology of the experiment
Identify patterns of influence of the surface roughness of coatings on their physical and mechanical properties of the following experiment was performed.Pellicle were made on the basis of alkyd enamel ПФ-115 and ПС-160 paint with different roughness.After complete curing of the pellicle of these samples were cut blade size 5,0x1,0 cm, the thickness of each sample was measured with a micrometer.The surface roughness of the coating was determined by means of the device profiler mark TR-100.Pellicle samples were tested for tensile testing machine brand ИР 50-57 with fixed crosshead speed of 87.5 m / s.

Results of tests
On fig. 1 and 2 diagrams of a stretching pellicle in coordinates «stress σelongation l  » are submitted.
The analysis of the received data testifies, that for investigated pellicle elastic -plastic character of destruction is characteristic.Irrespective of a kind of colourful structure, with increase in a roughness of a surface plastic deformations increase and are reduced elastic (tab. 1, 2).So, for pellicle on the basis of paint ПС -160 at roughness Ra=0,74 a micron the share of elastic making deformation in the general deformation makes упр   =0,935, and a share of a plastic component плас   0,065, and at a roughness of surface Ra=1,2 a micron 0,7857 and 0,2143 accordingly.Similar laws it is traced and for pellicle on the basis of paint ПФ -115.At a roughness of a surface of pellicle Ra=1,2mkm the share of elastic making deformation makes 0,481, and plastic -0,519, and at roughness Ra=1,74 a micron accordingly 0,281 and 0,719.The Found that paint pellicle based on ПС -160 is characterized mainly elastic deformation.Percentage of elastic deformation component in paint pellicle based on ПС -0,935 -0,7857 160 is, for a paint pellicle based on the ПФ -115 is characterized mainly plastic deformation.The proportion of plastic deformation component of 0,519-0,719.
For pellicle based on colorful compositions observed drop-down nature of the plot of "tensile strength-roughness" with a sharp decrease in strength to a certain value (R p = 45-55 kg / cm 2 at the roughness of the pellicle based paint ПФ-115 -1,4-1, 6 micrometers, and on the basis of the ink ПС-160 -0.8-1 microns).With further increase of surface roughness of pellicle occurs a smaller reduction of the tensile strength.
The submitted models allow to estimate prospective durability at a stretching depending on a roughness of a surface of coverings.The submitted models allow to estimate prospective durability at a stretching depending on a roughness of a surface of coverings.

Conclusions
Laws of change deformation properties of protective -decorative coverings are established depending on a roughness their surfaces consisting in decrease of durability and relative deformations at increase of a roughness of a

Fig. 4 .
Fig. 4. Dependence of durability at a stretching (1) and relative lengthening (2) from a roughness of a surface of a pellicle on the basis of paint ПФ-115 For pellicle on the basis of paint ПС-160 model (2) looks like

table 1
Deformation of pellicle on the basis of paint ПC -160, depending on the surface roughness