Testing And Analysis Of Mechanical Properties For Automotive Coatings

One of the important applications of coating/substrate composites is the automotive coating. After the development of over one hundred years, automotive coatings have developed from single-layer coating with single function to multi-layer coating with a variety of functions. The mechanical properties of the automotive coatings determine the surface performances (such as scratch resistance, service life, etc.) and affect the overall quality of vehicle. So, it is of great importance to study the mechanical properties of the automotive coating. In accordance with existing situation of research on automotive coatings, the following works were carried out in this paper:1. The stress-strain curves, elastic modulus, yield strengths and ultimate strengths of five kinds of automotive paints were obtained by using tensile testing method at room temperature. The parameters of the constitutive models of these paints were obtained.2. Nano-modification experiment on the topcoat and intermediate paint were carried out. The results showed that the mechanical properties of these paints changed after nano-particles (α-Al₂O₃, 5% in mass) were added into these paints. The mechanical properties of these paints were modified after adding both coupling agent and nano-particles into the composites.3. The scratch resistances of two different kinds of automotive coatings were evaluated by scratch tests. The results showed that the scratch resistance of metallic effect coatings was better than that of natural colored coatings. It was found that the coatings damaged easily with the scratch speed increasing.4. The scratch progress was simulated by FE software MARC for natural colored coatings. The numerical value of critical load was obtained. The scratch progress was simulated for nano-particle-reinfored coatings as well. The result showed that the critical load of nano-particle-reinfored coatings was higher than that of natural colored coatings.