# Parameter Study for the Ice Adhesion Centrifuge Test
## 1 Introduction  
The measurement of ice adhesion to surfaces is highly relevant for developers of icephobic materials that aim to reduce ice adhesion to an extent, at which only low energy is required to remove this ice. These so-called low ice adhesion surfaces would benefit many technical applications, such as in the energy and transport sector. Many different test methods have been developed over the past few decades to assess this functionality, addressing different complexity levels, ice types, and ice removal techniques. An extensive review on these methods is given by [PERSON] and [PERSON], with the aim to compare the different test designs with the needs for aircraft-relevant icing conditions. It included the centrifuge test as one of the most prominent methods for ice adhesion assessments, highlighting the benefit (throughput) but also the drawbacks (e.g., missing strain rate control, edge effects, and vibration) [1]. Despite these drawbacks, the centrifuge tests used for ice adhesion measurements appeared to be robust, easy to handle, and relatively accessible test devices that deliver reproducible results in a reasonable time [2; 3; 4; 5; 6; 7; 8]. They are generally used in a comparative manner, using reference or benchmark surfaces (e.g., aluminum, steel, unmodified coatings) to identify improvements (reduced ice adhesion) for the new developed materials. The tests support the iterative formulation work on low ice adhesion surfaces and allow the selection of promising candidates. As a tool for the initial assessments, they do not address the performance prediction in the target technical environment. In this study, the centrifuge test is also used for the assessment of relevant test parameters and influential surface properties. [PERSON] and [PERSON] used available test results from the literature to identify parameter correlations [1]. The first trend they observed is that the ice adhesion strength increaseswith decreasing temperatures, regardless of the used test method. The second raised aspect covers the effects of velocity (and resulting ice type). Derived from literature data, they identified a decrease in the maximum observed adhesion values for impact ice (accreted at different velocities) compared to static ice (formed by pouring water into a mold and freezing it) [1]. Unfortunately, the data consistency was rather poor, and the comparability of different test designs was limited. To account for this, in this study, we addressed the effects of the velocity during the ice formation process in the ice adhesion centrifuge test. The gained knowledge will contribute to an improved understanding of the influencing test parameters, paving the way to harmonize test designs based on substantiated test data. Besides the efforts on the development and definition of test designs for ice adhesion, many research activities are dealing with the understanding of the required surface characteristics to achieve low ice adhesion surfaces. Table 1 summarizes studies on the correlations between surface properties and ice adhesion test results, derived from centrifuge tests. The ice formation type is also indicated as one determining parameter of ice adhesion test results. The papers summarized in Table 1 mainly addressed material properties, such as the surface roughness and wettability, which are also covered in the current study. The surfaces used for the current study had to fulfil two main requirements: first, a high surface robustness (mechanical, chemical) to guarantee high repeatability of the tests without performance degradation; and second, a range of surface properties from rough to smooth