Evaluation of Application and Surface Preparation Parameters for Thermal Spray Coatings.

摘要

The U.S. Army Corps of Engineers uses thermal-sprayed zinc and aluminum coatings on hydraulic structures exposed to severe impact and abrasion damage caused by ice and floating debris. These coatings are also used widely for corrosion prevention on civil engineering structures across the nation. An experimental study of the twin-wire electric arc (TWEA) spraying of zinc and aluminum coatings was conducted to demonstrate the suitability of this technology for Army applications. Experiments on six materials systems were conducted using classical and statistically designed fractional-factorial schemes. TWEA process parameters studied included current, spray angle, spray distance, and system pressure. A systematic design of experiments was utilized in order to display the range of processing conditions and their effect on the resultant coating. The coatings were characterized with bond strength and deposition efficiency tests, and optical metallography. Coating properties were quantified with respect to roughness, hardness, porosity, oxide content, bond strength, and microstructure. Coating performance was evaluated and quantified with erosion testing, and a parameter-property-performance relationship was developed for each materials system.