Ion-machining ceramics for transmission electron microscopy

Abstract

Thinning various materials for transmission electron microscopy (TEM) by ion machining has been discussed in the literature. Christie et al. [1] have listed many of these materials and briefly discussed a method of their preparation for T E M through ion machining. Sample dimensional requirements prior to ion machining are brought out by Barber [2], but nowhere in the literature are the techniques required for sample preparation of ceramic materials discussed. Reducing bulk materials to thin usable samples ( ~ 25/~m) can consume 50% of the total sample preparation time, including ion machining. To minimize sample preparation time, it is essential to have a simple reduction technique that produces high yields. This paper discusses a technique that has been successfully used to prepare alumina (A1208) samples for TEN[ work. An I M M I I I I 1 ion-milling machine was used for all of the experiments. The multihole anode and cathode was used, however, the single hole anode and cathode presently available would probably reduce the ion-machining time. The electron microscope used was a JE1V[-7, ~ operated at 100 KeV. The first step in preparing ceramic material for ion machining is to reduce the bulk material to a size and shape adaptable to both the ion machine and TE1V[ stages. The starting material for this study was 12.7 mmX 12.7 m m × 1.6 ram. The sample was mounted on a steel plate (measuring about 50 mm × 75 mm x 6 mm) with a high-temperature wax ~ (see Fig. 1). The plate was heated to a temperature just sufficient to allow the wax to run smoothly. The sample was pressed firmly into the wax, down to the plate, and subsequently cooled.