详情

原文传递 Application Parameters for Arc Spray Metallized Coatings

题名：	Application Parameters for Arc Spray Metallized Coatings
作者：	Al BEITELMAN
关键词：	Parameters ; Arc Spray Metallized Coatings
摘要：	The process for applying metallic coatings to steel substrates has been available for many years. These metallic coatings are known to provide long-term corrosion protection to steel structures exposed to both atmospheric and immersion conditions but little information is available regarding the coating application parameters and their effects on performance. Application on navigation structures to be immersed in fresh and sea water is often performed in the field where nonuniformity of surface preparation and irregularity of handling the metallizing equipment may have a significant effect on coating quality. Two studies were conducted using arc spray metallizing equipment. The first study used TAFA equipment and applied three metals using 3.175 mm wire. The second study duplicated the first using Thermion equipment, applied two additional metals, and used both 3.2 mm and 4.8 mm wire. The metals tested were: (1) zinc: aluminum (85:15) alloy, (2) aluminum, (3) zinc, (4) zinc: aluminum (85:15) pseudo alloy, and (5) aluminum/aluminum oxide (90:10) alloy. The variables evaluated were: stand-off distance, spray angle, amperage, atomization air pressure, and wire diameter. The applied coatings were evaluated for pull-off adhesion, cavitation erosion resistance, and porosity and oxide content. Additional specimens were prepared in both studies to evaluate the adhesion characteristics of the coatings in relation to surface preparation variables. Variables included four abrasives (aluminum oxide, copper slag, steel shot, and steel grit) each producing profiles of 25 and 75 microns. This work revealed a significant difference in adhesion between the steel shot and steel grit blasted surfaces. As a result a follow-on study was conducted to determine if recycling of steel grit would result in a rounding of the abrasive particles and the effect this might have on the adhesion of a metallized coating. Steel grit was recycled up to 200 times and periodically evaluated for its angularity. At given degrees of angularity the abrasive was used to prepare panels that were metallized with zinc: aluminum (85:15) alloy and evaluated for any differences in adhesion values. The results of the studies revealed optimal conditions as well as variations in equipment settings and gun handling that can still be expected to apply coatings with acceptable characteristics.
总页数：	Proceedings of the 30th PIANC-AIPCN Congress. Sydney Australia. 22-26 Sept. 2002. pp13
报告类型：	科技报告