Coating Qualities Deposited Using Three Different Thermal Spray Technologies in Relation with Temperatures and Velocities of Spray Droplets

• Main Authors: Yasuyuki Kawaguchi, Fumihiro Miyazaki, Masafumi Yamasaki, Yukihiko Yamagata, Nozomi Kobayashi, Katsunori Muraoka
• Format: Article
• Language: English
• Published: MDPI AG 2017-02-01
• Series: Coatings
• Subjects: spray droplet from wire; temperature; velocity; gas flame spray; wire arc spray; wire plasma spray; coating quality
• Online Access: http://www.mdpi.com/2079-6412/7/2/27

Three guns based on different thermal spray technologies—namely, gas flame spray, wire arc spray, and wire plasma spray—were operated at each best cost–performance condition, and the resulting spray droplets and deposited coating qualities were investigated. For the former, a simple optical monitoring system was used to measure temperatures and velocities of spray droplets ejected from the guns. On the other hand, for the latter, qualities of coating layers on substrates—namely, surface roughness, atomic composition, hardness, adhesive strength, and porosity—were characterized. Then, these coating qualities were discussed with respect to the measured temperatures and velocities of spray droplets, which revealed novel features in the coatings that have not been seen before, such as atomic composition and hardness strongly dependent on temperature and environments of droplets towards the substrates, and porosity on velocity of droplets impinging onto the substrates.