材料孔隙率测试方法的研究

Study on Porosity Test Method of Materials

孔隙率是材料研发和使用过程中重要参数之一.不同材料的孔隙率发挥的作用不同.结合气体膨胀置换法和振动堆积法研究了不规则可浸湿和不可浸湿的块状材料、粉末材料的孔隙率测试方法.试验结果表明,气体膨胀置换法测试不规则可浸湿材料的外观体积与常规排水法的测试结果一致,所以运用该方法来测试不可浸湿的块状材料,解决了不可浸湿的块状材料外观体积的测试瓶颈.振动堆积法测试粒径小的粉末样品的近似外观体积,解决了粉末样品外观体积无法测试的问题.基于理想气体状态方程,通过测试两个已知体积样品仓的压强值,从而分别计算出不规则可浸湿、不可浸湿的块状材料和粉末材料的真实体积.通过真实体积除以外观体积,计算得出了扣除材料内部孔隙和颗粒间孔隙后的百分比,即样品中非孔隙的百分比,再用100%减去非孔隙百分比,从而建立了材料孔隙率计算方法.

Porosity is one of the important parameters in the research and use of materials.The porosity of different materials plays different roles.The porosity testing methods of irregular wettable and non-wettable bulk and powder materials were investigated by the gas expansion replacement method and vibration stacking method.The experimental results showed that the appearance volume test result of irregular wettable materials by the gas expansion replacement method was consistent with the test results by the fluid displaced method.So the appearance volume test bottleneck of irregular wettable materials was solved by the gas expansion replacement method.The approximate appearance volume of the powder samples with a small particle size was tested by the vibration stacking method,solving the problem that the appearance volume of powder samples cannot be tested.Based on the ideal gas state equation,the true volumes of irregular wettable and non-wettable bulk and powder materials were calculated by testing the pressure values of two known volume sample compartments,respectively.A method for calculating the porosity of the materials was established by dividing the true volume by the exterior volume,calculating the percentage after subtracting the internal pores of the material and the pores between the particles,that is the percentage of non-pores,and then subtract the percentage of nonpores by 100%,thus establishing the calculation method of the porosity of the material.