(5f) Characterization of Reference Particles of Transparent Glass by Laser Diffraction Method

The validation of particle size analysis by laser diffraction method should be done using standard reference particles, whose size distribution is better to have a range over one decade of size, according to ISO 13320-1. Form such background, the group of the late emeritus professor Koichi Iinoya, Kyoto University had started to investigate from 1990 in International Fine Particle Research Institute, and produced spherical particles of two types and four different size ranges of from 1 μm to 650 μm, i.e. 8 kinds of samples, in 1996. The late professor Brian Scarlett, Delft University of Technology and University of Florida, tried to make the round robin test using these standard reference particle candidates by laser diffraction (LD) method with collaborating on laboratories of universities and industries. As a result of this collaboration, Yoshida et al. measured the particle size distributions of two kinds made by the barium titanate glass within those candidates, which were done by modified sedimentation balance (SB), electrical sensing zone (ESZ) and scanning electron microscope (SEM) methods, and reported in Advanced Powder Technology. However the round robin test using LD method has not finished yet. The Standard Powders Committee in the Association of Powder Process Industry and Engineering, Japan (APPIE) prepared the APPIE Standard, SAP10-03, on November 2003 based on the report written by Yoshida et al., while Technical Group of Measurement and Control in APPIE carried out the round robin test of barium titanate glass standard reference candidates by LD method. Two kind of standard reference particles consisted of barium titanate, named MBP 1-10 and MBP 10-100, are defined in SAP10-03, and the particles suited SAP10-03 Standard are distributed by APPIE from April 2004. In this paper, we reported the characterization of MBP 1-10 and MBP 10-100, and the results of the round robin test by LD method, which were conducted in order to certify the request for ISO 13320-1. The size distribution measured by ESZ method agreed well with those by SB and SEM methods. Eight manufactures and distributors in Japan joined in the round robin test and measured two kinds of Standard Reference Particles of APPIE during on summer 2003. 1-10 μm sample (MBP 1-10) was well dispersed in water without detergent, but a few drops of detergent sometimes needed for dispersing 10-100 μm sample (MBP 10-100). For MBP 1-10, the mean particle size by LD methods was slightly smaller than that by SEM method, and was within the certified range of Standard Reference Particles of APPIE. For MBP 10-100, the mean particle size by LD methods agree well with that by SEM method and within the certified range, but the discrepancy of one instrument in larger size range became larger than the certified range. The size distributions of calcium carbonate and talc powders were also measured by the same instruments joined in the round robin test. The comparing result among instruments is discussed for the typical example measured actual samples by LD method.