Accession Number : AD0624484

Title :   MACHINING HIGH PURITY ALUMINA.

Descriptive Note : Quarterly rept. no. 3, 1 Jan-1 Apr 65,

Corporate Author : LINDEN LABS INC STATE COLLEGE PA

Personal Author(s) : Marshall,P. A. ,Jr. ; infield,J. M. ; Beyer,S. J.

Report Date : 01 MAY 1965

Pagination or Media Count : 30

Abstract : It was demonstrated that a pre-selected commercial grade, high-purity alumina (96%) can be made friable by immersion in aqueous hydrofluoric acid (52%) so that it can be machined with conventional cutting tools and then reconstituted to acceptable physical characteristics, i.e., dimensional control, porosity (open and closed pores), water absorption and a high pressure fuchin dye penetration. Further it has been demonstrated that a pre-selected, presently available commercial grade 96% alumina fired at cone 31 (1680 C) can be reconstituted at cone 33 (1745 C) to a purity level suggestive of approaching the theoretical density of alpha corundum (4.00). A basis is given for aiding in the selection of those alumina bodies which are most apt to accommodate to this new technique. Also, it is concluded that for optimizing this process, it might be well to design a body formulation which will adapt itself to this process rather than make use of existing bodies. Factors other than chemical composition, such as the primary raw material grain size and fired grain size, must also be considered. (Author)

Descriptors :   (*MACHINING, CERAMIC MATERIALS), (*ALUMINUM COMPOUNDS, OXIDES), (*CERAMIC MATERIALS, MACHINING), HARDNESS, HYDROGEN COMPOUNDS, FLUORIDES, PHYSICAL PROPERTIES, HEAT TREATMENT, PURIFICATION, DENSITY

Subject Categories : Ceramics, Refractories and Glass
      Test Facilities, Equipment and Methods

Distribution Statement : APPROVED FOR PUBLIC RELEASE