Coating Effect in XRFS Analysis with Pressing Discs

Coating effect in XRFS analysis with pressing discs was proposed. It was discovered that the measured results of MgO was lower,while Al2O3 was higher in castable alumina and magnesia by XRFS,and the degree of the discrepancy was equal. This phenomenon could not be significantly changed by grinding sample to lower size with agate mortar. Thus,it was not affected by the particle size of the sample. When alumina and magnesia were grinded to 0.087 mm,and then mixed in according to the amounts of MgO and Al2O3 in the castable alumina and magnesia,the difference of the results between the pressing discs and melted discs was very small. Thus,the phenomenon could not be explained by mineral effect either. Therefore,the idea of coating effect was proposed. The coating effect in original research literature could be found. And the difference between the coating effect,the particle size effect,and the mineral effect was given.