MACHINING HIGH PURITY ALUMINA.

The report contains a general discussion of the purposes of the demonstration to machine high purity polycrystalline alumina by prior treatment with HF. It then goes into the investigations of samples of three known manufacturers of high purity polycrystalline alumina. The investigation covers primarily two areas. The first is the rate of penetration of the acid into the alumina. The second area is the machine tool wear produced by turning the sample in a lathe. The report then goes into reconstitution firing temperatures and the problems which were evident at this stage. The report then covers dimensional stability of the treated alumina before and after the reconstitution. Also considered is the preparation of the area for the fluorination of the engineering phase pieces and some of the precautionary measures built into the area.