Introduction

On 8 April we received a set of three samples of magnesium hydroxide with the request that we image the particles for purposes of comparison of particle size and morphology. The samples were assigned MVA Scientific Consultants sample identification numbers as follows:

Sample Description MVA Number

AR3-1-05-1 94% H₂0 6% Mg(OH*) 6287Q0515

AR3-1-05-D Dry Cell 6287Q0516

AR3-1-05-2 40% H₂0 60% Mg(OH*) 6287Q0517

Imaging was performed in our laboratory on 13 and 14 April 2005.

Methods

A small portion of each sample was dispersed in deionized, particle free water, and a droplet placed on a polished carbon planchette and allowed to dry. The dried samples were placed in our JEOL JSM 6500F field emission scanning electron microscope where images were obtained at magnifications up to 220,000x. The images were digitally recorded and annotated in Adobe Photoshop.

Results

The images obtained are attached as an appendix to this report. Comparison of the images of samples AR3-1-05-1 and AR3-1-05-2 shows very different particle morphologies between the two samples. Sample AR3-1-05-1 contains principally flakes with diameters up to a few hundred nanometers and thicknesses of only a few nanometers, often arranged in larger particles with appearances similar to “desert rose” concretions. In contrast, sample AR-3-1-05-2 consists of blocky, roughly equant particles with sizes down to tens of nanometers and occurring as conglomerates of micrometer dimensions. Sample AR3-1-05-D appears to be formed from aggregates of the flakes seen in sample AR3-1-05-1, gathered and formed into rounded particles of many micrometers dimension by a drying liquid droplet.

APPENDIX