R. Mccullough, R. J. Molz, D. Hawley, Sulzer Metco, Westbury, NY
Process mapping is an ideal method for tracking coating characteristics and relating those characteristics to the conditions of the particle. Utilization of a process map of particle velocity and temperature to optimize coating characteristics for tungsten carbide coatings sprayed with the Triplex Pro 200 plasma gun demonstrates an effective use of this recently developed tool for plasma spray. An operating window of particle conditions in terms of particle velocity ranging from 500 to 650 m/sec and temperature ranging from 2300 to 2600 C is determined as part of a Design for Experiment and coating samples produced within that operating window. The results allow determination of optimum performance characteristics in terms of coating stress, hardness, carbide distribution, porosity, etc. for a desired coating as well as factors relating to the process that determine those characteristics. Multidimensional maps show relationships between the energy state of the particle and specific coating characteristics such as particle velocity/temperature versus coating stress as measured with an Almen strip.
Summary: Presentation of results obtained from spraying of tungsten carbide coatings using the Triplex Pro 200 Plasma Gun to meet specific coating specifications. Analysis of coating results and development of process maps that relate the properties of the coating to conditions of the particle using six sigma design for experiment procedures and methods.
