ISO 4628-2:2016标准是涂层退化评估的重要标准之一，主要用于评估涂层表面的气泡程度。气泡是涂层表面常见的缺陷之一，会影响涂层的外观和性能。因此，对气泡的评估和控制是涂层生产和应用中的重要问题。

该标准规定了气泡的数量、大小和密度等参数，以及评估气泡程度的方法和标准。其中，气泡的数量和大小是通过视觉检查和显微镜观察来确定的。视觉检查主要是通过肉眼观察涂层表面的气泡数量和大小，而显微镜观察则可以更准确地确定气泡的大小和形状。

在评估气泡程度时，该标准规定了四个等级，分别为0级、1级、2级和3级。0级表示涂层表面没有气泡，1级表示气泡数量较少，2级表示气泡数量较多，3级表示气泡密集且大小不一。评估时，需要根据气泡的数量、大小和密度等参数来确定涂层的气泡程度。

除了气泡程度的评估，该标准还规定了其他涂层表面缺陷的评估方法，如裂纹、剥落、起皮等。这些评估方法可以帮助涂层生产和应用中的质量控制和问题解决。

相关标准
ISO 4628-1:2016 Paints and varnishes — Evaluation of degradation of coatings — Designation of quantity and size of defects, and of intensity of uniform changes in appearance — Part 1: General introduction and designation system
ISO 4628-3:2016 Paints and varnishes — Evaluation of degradation of coatings — Designation of quantity and size of defects, and of intensity of uniform changes in appearance — Part 3: Assessment of degree of rusting
ISO 4628-4:2016 Paints and varnishes — Evaluation of degradation of coatings — Designation of quantity and size of defects, and of intensity of uniform changes in appearance — Part 4: Assessment of degree of cracking
ISO 4628-5:2016 Paints and varnishes — Evaluation of degradation of coatings — Designation of quantity and size of defects, and of intensity of uniform changes in appearance — Part 5: Assessment of degree of flaking
ISO 4628-6:2016 Paints and varnishes — Evaluation of degradation of coatings — Designation of quantity and size of defects, and of intensity of uniform changes in appearance — Part 6: Assessment of degree of chalking by tape method