Evaluation of Surface Preparation and Application Parameters for Arc- Sprayed Metal Coatings.

摘要

The U.S. Army Corps of Engineers uses an 85:15 zinc:aluminum alloy coating on hydraulic structures exposed to severe environments, such as those areas on a structure subject to impact and abrasion damage caused by ice and floating debris. Properly applied coatings of this type have lasted 8 to 10 years. However, the Corps has experienced premature failure of these systems due to inappropriate surface preparation and application procedures. Much advancement in metal spray technology has occurred in recent years. Other alloys have been designed for metal spray application. These metals combined with technological advances in application equipment may provide better performance and yield more productive application rates. Under contract to the U.S. Army Construction Engineering Research Laboratory (CERL), KTA-Tator, Inc. investigated the effects of surface preparation and application parameters on the performance characteristics of 85:15 zinc:aluminum alloy versus four other materials used for metal coating (metallizing) of Corps structures. These attributes were evaluated by using the electric arc process of metallizing. The effects of surface preparation and application parameters on adhesion, cavitation, and erosion, and porosity and oxide content were investigated, and a statistical analysis of the results was performed. Based upon the results of this study, a list of suggested surface preparation and coating application parameters as well as minimum tensile adhesion values (based upon use of a pneumatic adhesion tester) was developed for each respective material.