薄膜低温热膨胀系数测量方法研究

热膨胀系数是材料在低温应用中最重要的力参数之一,薄膜材料的许多性质与其同种块材差别较大.针对预应力大小对测试结果的可能影响,提出了两种薄膜低温热膨胀系数的测量方法,直接测量法和间接测量法.测试温度范围为室温至77 K,可以进行施加不同预应力和在更低温度下进行测量.

Research on measurement method of coefficient of thermal expansion of thin film at low temperature

The coefficient of thermal expansion(CTE) is one of critical design parameters for the application of materials at low temperature.The available study results demonstrate that the thin films have different properties from their bulk counterparts.However,few techniques have been developed to measure the CTE of thin films at low temperature.Furthermore,the possible effect of the applied stress levels on CTE testing results does not receive enough attention.Two novel methods,one is direct and another is indirect for measuring the CTE of thin films under different applied stress levels at low temperature,are proposed.The testing temperature is from room temperature to 77 K and can be reached to lower temperature.Advantages of two methods are also discussed.