1.1 本试验方法涵盖了用于金属和非金属基材上金属和非金属涂层无损测量的β背散射计。 1.2 该测试方法测量每单位面积的涂层质量，也可以用线性厚度单位表示，前提是涂层密度已知。 1.3 只有当涂层和基材的原子序数或等效原子序数相差适当时，试验方法才适用（见 6.2 ). 1.4 β反向散射仪器使用了许多不同的放射性同位素。虽然这些同位素的活性通常很低，但如果处理不当，它们可能会带来危险。本标准无意解决安全问题和放射性材料的正确处理。用户有责任遵守有关放射性材料处理和使用的适用州和联邦法规。 一些州要求放射性同位素的许可和注册。 1.5 以国际单位制表示的数值应视为标准值。本标准不包括其他计量单位。 1.6 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 1.7 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。 ====意义和用途====== 4.1 涂层的厚度或单位面积质量通常对其性能至关重要。 4.2 对于某些涂层-基材组合，β背散射法是无损测量涂层的可靠方法。 4.3 如果规定了单位面积质量，则试验方法适用于厚度规范验收。如果规定了涂层厚度，并且涂层材料的密度可能会变化或未知，则不适用于规范验收。

1.1 This test method covers the beta backscatter gages for the nondestructive measurement of metallic and nonmetallic coatings on both metallic and nonmetallic substrate materials. 1.2 The test method measures the mass of coating per unit area, which can also be expressed in linear thickness units provided that the density of the coating is known. 1.3 The test method is applicable only if the atomic numbers or equivalent atomic numbers of the coating and substrate differ by an appropriate amount (see 6.2 ). 1.4 Beta backscatter instruments employ a number of different radioactive isotopes. Although the activities of these isotopes are normally very low, they can present a hazard if handled incorrectly. This standard does not purport to address the safety issues and the proper handling of radioactive materials. It is the responsibility of the user to comply with applicable State and Federal regulations concerning the handling and use of radioactive material. Some States require licensing and registration of the radioactive isotopes. 1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 4.1 The thickness or mass per unit area of a coating is often critical to its performance. 4.2 For some coating-substrate combinations, the beta backscatter method is a reliable method for measuring the coating nondestructively. 4.3 The test method is suitable for thickness specification acceptance if the mass per unit area is specified. It is not suitable for specification acceptance if the coating thickness is specified and the density of the coating material can vary or is not known.