Materials Science Forum Vol. 689

Abstract: The corrosion weight loss method and polarization curve measurement were conducted to study the effects of the complex inhibitor of sodium tungstate and urotropine on the corrosion of 304 stainless steel in the 3.5% NaCl solution. The results indicated that the complex inhibitor has good synergistic inhibitory effect for stainless steel in the NaCl solution. Combining sodium tungstate and urotrpine at a total concentration of 500 mg/L, when the mass ratio of sodium tungstate to urotrpine was 7:3, the inhibitory effect was optimum. In addition, the probable inhibitory mechanism was analyzed.

Abstract: In this paper, the morphology characteristic of tensile test fracture of polysulfide sealants immersed in oil for different time was observed through scanning electron microscopy. Combined with the performance data of tensile test, the effect of oil immersion time on the properties and fracture behavior of sealant was studied. The results show that the fracture of polysulfide sealants includes rough region and flat region. After being immersed in oil, the area of rough region diminishes and the roughness of fracture decreases. Within 168h, oil immersion time has little effect on the tensile strength and elongation of sealants.

Abstract: The explosion of liquid carbon dioxide tanks are extremely rare in the world, this article describes the 125 m³ liquid carbon dioxide tank explosion that happened on a ship. This paper gives a comprehensive analysis and calculation on the explosion energy and hazard radius as well as the causes of the accident, with the explosion energy being converted to TNT equivalents. Tank explosion radiuses leading to death, serious injury and different degrees of destructions are also obtained via theoretic calculation. According to the calculation, this article points out that the direct cause of explosion is that the designer confuses the concept of " Low-temperature vessels" with the concept of " Low-temperature and Low-vessels Low Stress vessels". The reasons of the tank explosion accident are not only the mistaken design but also the operating violation. Finally the article also makes a reflection from four different perspectives.

Abstract: To develop new non-toxic antifouling coating, some fouling-release(FR) coatings based on fluoro-copolymer and silicone polymer were formulated. Coatings specimens were rotated in a laboratory device at different simulating speeds of a ship for some periods. The film thickness, surface roughness, water contact angle of all coatings were measured and investigated. The relationship between the performance and testing time, and the effect of simulating speed on the performance were studied and discussed. The research results show that the time spent on evaluating the performance of ship antifouling coatings was shortened. The film thickness of all coatings decreases with test time. FR antifouling coatings surface roughness increase slowly, and their surface contact angle decrease gradually with time. Increasing of the simulating speed will accelerate the surface of all the coatings trend to rougher, increase the ablation rate of the coatings and the change of water contact angle of FR coatings.

Abstract: A study on the kinetics of β grain growth of a fine-grained, hot-rolled TB-13 alloy was carried out by isochronal and isothermal solution treatments. The grain size of the as-rolled and as-solution-treated samples was determined by metallographic observation using the linear intercept method. The kinetic equations and the Arrhenius-type equation were applied to calculate the β grain growth exponent and the activation energy for β grain growth at special temperatures. The results showed that the β grain growth rate decreased with elongating solution treated time, but increased with increasing solution treated temperature. The β grain growth exponents (n) were 0.394, 0.403 and 0.406 during the solution treated temperatures at 1103K, 1153K and 1203K, respectively. The values of n increased with increasing solution treated temperature and the determined activation energy (Q_m) for β grain growth after holding for 0.5h at 1103K-1203K was around 156KJ/mol.