Papers by Keyword: Artificial Degradation

Abstract: The objective of this study was to evaluate the effect of three types of surface protectors: Protector with and without ultraviolet pigment and hydrophobic protector, on cracking and discoloration of Pinus radiata wood, after accelerated aging caused by temperature variation, UV-A radiation and humidity. For the tests, a QUV/Spray model accelerated aging chamber was used, which simulates the spectrum of radiation emitted by the sun under controlled climatic conditions in accordance with the EN 927-6 standard. The main results show that after 11 cycles (1848 hours) of testing, the color change decreased and the presence of the number and size of cracks occurred in the order of samples with Hydrophobic protection, followed by samples with UV pigment protector. and finally, in sample with protector without UV pigment. When wood is exposed to UV radiation, it undergoes photo-oxidation, causing an alteration of the properties and the original colour. This radiation burns the surface cells (lignin) of the wood, this effect produces cracking and flaking of the wood.

Abstract: In this paper, as a fundamental study to evaluate fracture characteristics and material degradation by corrosion, evaluated electrochemical corrosion and corrosion fatigue characteristics of CF8A steel using as a material of the piping system in nuclear power plant. CF8A steel was artificially degraded at 400°C for 3 months. The environmental test condition is 3.5wt.% NaCl solution of room temperature. Corrosion rate of degraded CF8A steel in NaCl solution of room temperature increases with concentration of NaCl solution increase. However, concentration of NaCl solution will be more than 4.0wt.%, it shows decreasing tendency. Crack growth rates of degraded and not-degraded CF8A steel in air condition do not show remarkable difference. However, in 3.5wt.% NaCl solution, crack growth rates of them showed higher than ones in air. Particularly, crack growth rate of degraded material remarkably increases compare to one of notdegraded material.