Standards Development

Scope

This document specifies the testing methods exclusively for determining the adhesion rate of electrostatic spraying dry powder bisque coating.

Purpose

Electrostatic spraying technology has gained popularity and widespread use due to its various merits, such as energy efficiency, maximum material usage efficiency, simplified enamelling techniques, and high degree of automation. Currently, over 100 enamel factories worldwide utilize this technology for applications including kitchenware, water heaters, architectural enamel panels, and more. Among the electrostatic spraying technologies, the quality of dry powders plays a pivotal role in achieving high quality enamel products. 

The consumption of dry powders accounts for approximately 20% of the global porcelain enamel consumption, with an anticipated annual growth rate of around 5%. Therefore, it is imperative to establish a robust evaluation system for assessing the quality of dry powders in order to ensure and enhance the overall quality of enamel products. According to the electrostatic spraying schematic, it is crucial for the attractive electrostatic force between the charged particles and the steel surface to be sufficiently strong in order to firmly hold them in place. Additionally, it is important for this electrostatic force to be retained during transportation. Failure to do so may result in previously deposited particles falling off before they can fuse together and form a uniform enamel layer. Therefore, ensuring good powder bisque coating adhesion is essential as it guarantees that a majority of the deposited powder remains adhered to the workpiece even after a certain period of time or during movement and firing processes subsequent to spraying. However, the absence of a standardized test method for measuring the adhesion rate of electrostatic dry powder bisque coating raises concerns regarding the accuracy and comparability of such measurements. Various companies employ different testing methods, including shaking and striking techniques. Therefore, it is imperative to establish clear guidelines for the test methods used, as well as standardize enamel samples, setups, and testing conditions. The purpose of this proposal is to provide a common language for the assessment and evaluation of adhesion performance in electrostatic dry powder bisque coating, aiming to improve the quality of both dry powders and enamel products. Furthermore, developing an ISO standard regarding test methods for measuring adhesion rate of dry powder bisque coating will enable interoperability among products from different companies, safeguard the crucial interests of businesses and consumers, and provide a reliable foundation for market regulation