溶解法测定铝基复合材料中碳化硅增强体体积含量

摘要

For aluminum matrix composites that are difficult to distinguish between reinforcements and ma-trix structures by metallographic microscope,it is difficult to accurately measure the volume fraction of re-inforcements in aluminum matrix composites by national standard method (GB/T 32496—2016).Dissolu-tion method was applied to the determination of volume fraction of SiC reinforcement in aluminum matrix composites.The aluminum matrix was firstly digested with HCl (1+1),HF and H2O2.Then SiC rein-forcement was collected by glass filter crucible and quantitative filter paper,respectively.The corrosion behavior of the dissolving solution on SiC reinforcement was investigated.The results showed that alumi-num matrix could be completely dissolved by adding 10-20 mL HCl (1+1),3-5 mL HF and 3-6 mL H2O2 sequentially.The precision results showed that the relative standard deviation (RSD)were not more than 0.1% (n=9),which could satisfy the determination demand of SiC volume fraction in aluminum matrix composites.The result of filter paper method was more economical and stable than that of glass filter cru-cible suction method.The filter paper method was recommended to determine SiC volume fraction in alu-minum matrix composites.The analytical values of the aluminum matrix composite sample analyzed by fil-ter paper method were in agreement with the theoretical values.%对于金相显微镜下难以区分增强体和基体组织的铝基复合材料而言,国家标准方法GB/T 32496—2016难以准确测量铝基复合材料中的增强体体积含量.实验以 HCl(1+1)、HF和 H2O2为溶解液消解铝基体,再采用砂芯坩埚和滤纸两种方法收集 SiC,采用溶解法测定铝基复合材料中SiC增强体体积含量.实验探讨了溶解液对SiC增强体的腐蚀行为.结果表明:依次加入10~20 mL HCl(1+1)、3~5 mL HF和3~6 mL H2O2可将Al基体组织溶解完全.精密度试验表明,待测SiC体积含量的相对标准偏差(RSD)均不大于0.1%(n=9),能满足铝基复合材料中SiC体积含量的检测要求.相比砂芯坩埚抽滤法,滤纸法较经济且结果稳定.推荐采用滤纸法进行铝基复合材料中SiC体积含量测试.采用滤纸法分析铝基复合材料样品,测定值与理论值吻合良好.