高温锰系磷化液的检测准确性及测量系统分析

Analysis on Detection Accuracy and Measurement System for High-temperature Manganese Phosphating Solution

用酸碱滴定分析法对高温锰系磷化槽液的总酸及游离酸值进行滴定,国际、国内标准是用指示剂颜色变化来作为总酸及游离酸值终点的判定,误差大,产品质量受影响。为了提高检测的准确性,规定滴定总酸、游离酸的PH值,采用PH计及PH标准缓冲溶液对PH值进行校正代替观察指示剂颜色的变化判断总酸、游离酸值。分析和排除影响指示剂变色的原因,规定检测温度,对取样和检测进行标准化,通过测量系统分析,滴定准确。

Total acidity value and free acidity value of high-temperature manganese phosphating solution have been always determined by observing the color changing in an indicator while conducting the titrating of acid-base,which unavoidably gives arise to larger error and poor product quality.Therefore,in order to realize more accurate detection,PH values of total acidity and free acidity are specified,PH meter and standard PH buffer solution are applied for correction rather than observing the color changing in an indicator.Through analysis and elimination on factors which lead to the color changing in an indicator,as well as the specification of temperature and the standardization of sampling and detection,the titration as described is proved to be accurate via measurement system analysis.