Which of the following properties contributes to a coating's resistance to physical wear?

Impact resistance is a critical property that contributes to a coating's overall ability to withstand physical wear. When a coating is subjected to physical stress, such as impacts or abrasions from external forces, its capacity to absorb and dissipate that energy without cracking, chipping, or peeling is vital for maintaining its integrity and functionality. High impact resistance indicates that the coating can endure sudden force without suffering damage, making it particularly important in environments where it will be exposed to frequent physical contact or harsh conditions.

On the other hand, while chemical resistance, thermal conductivity, and optical clarity are essential properties for different performance aspects of coatings, they do not directly address the wear and tear that coatings face from physical interactions. Chemical resistance is more about the coating's ability to withstand corrosive substances; thermal conductivity relates to heat transfer; and optical clarity pertains to the transparency of the coating. Hence, they do not contribute directly to the physical durability of the coating as impact resistance does.