Experimental and Calculational Study on Effects of Flow Additive on Flowability of Fine Coating Particles

Danni Bao, Long Sang, Junqing Xie, Haiping Zhang, Hui Zhang, Jesse Zhu

Research output: Journal PublicationArticlepeer-review


A method of encapsulation of inorganic additives with organic materials was developed to improve the fine power flowability and film quality for powder coating. The flowability tests angle of repose (AOR) and avalanche angle (AVA) were conducted for the coating samples to characterize the effectiveness of the encapsulated additives on group C fine powder flowability. The results show that both AOR and AVA are significantly affected by the encapsulating materials, the encapsulating material weight percentage, as well as the total loading ratios of additives added in fine powders. Polyester shows the best performance on the modification of the additive due to the high similarity to host powder coating. AOR/AVA first decreases and then decreases with the encapsulating material weight. An optimum percentage exists at approximately 10%. A similar trend is observed with the additive loading ratio, and the minimal AOR/AVA is obtained at additive loading ratios between 0.5% and 0.8%. The effective surface area coefficient (η) was introduced to improve the adhesion force model to determine the optimum additive loading ratio for various host particle and additive particle sizes, which agrees well with the experimental results.

Original languageEnglish
Article number2
Issue number1
Publication statusPublished - Jan 2023
Externally publishedYes


  • adhesion force model
  • effective surface area
  • fine powder coating
  • flow additive
  • flowability
  • nano particle encapsulation

ASJC Scopus subject areas

  • Bioengineering
  • Chemical Engineering (miscellaneous)
  • Process Chemistry and Technology


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