基于激光干涉法精密测量材料线膨胀系数装置的研究

The Precise Measurement of Linear Expansion Coefficient for Materials with Laser Interferometric Dilatometer

阐述了中国计量科学研究院自行设计和研制的基于激光干涉法材料线膨胀系数测量的装置。该装置采用单频激光干涉法测量样品长度变化。为了消除样品自重带来的影响，进行了新的光路设计，以实现材料线膨胀系数的绝对测量，其分辨率小于1nm。在常温下采用美国国家标准技术研究院（NIST）标准参考物质硼硅酸玻璃进行了测试，测得材料线膨胀系数与NIST公布值的相对偏差在1．2％以内，结果证明，该测量装置的性能是可靠的。

A laser interferometric dilatometer designed for measuring linear expansion coefficient by the National Institute of Metrology （NIM）is described. In the dilatometer the single frequency laser interferometer is adopted to measure the change of the sample length. For reducing the negative effect of the gravity of sample, a new design of laser interferometer was put forward and could realized the absolute measurement of linear expansion coefficient of materials. The resolution of this dilatometer is within 1 nm. With room temperature nearby, the linear expansion coefficient of the standard reference materials of NIST-borosilicate glass was measured. The comparison indicates that the measured values of linear expansion coefficient agree with those of NIST within a relative deviation of less than 1.2%. The results prove this dilatometer is reliable.