Accession Number : AD0638453

Title :   SEMI-CONTINUOUS PRESSURE SINTERING.

Descriptive Note : Summary rept., 3 May 65-29 Apr 66.

Corporate Author : BOEING CO SEATTLE WASH AEROSPACE GROUP

Personal Author(s) : Rice,Roy W. ; Hunt,James G.

Report Date : MAY 1966

Pagination or Media Count : 67

Abstract : A process of semi-continuous pressure sintering was proposed wherein a ceramic powder was to be encapsulated in a suitable metal tube and subsequently densified by combinations of rolling, swaging and drawing at various temperatures. Requirements for development of the process were established and essentially met. No adaptation of facilities was found necessary for room temperature rolling or for swaging at temperatures of at least 1100C. Hot drawing facilities were readily adapted using ZrO2 dies shrunk into TZM holders. Stainless steel tubes were found to have adequate chemical compatibility with both the process parameters and the MgO. These tubes were also found to be generally mechanically compatible with the ceramic and process parameters for all operations except hot drawing. However, hot swaging which was readily accomplished, appears to do the job expected of hot drawing. Fine, active MgO powders showed good compaction, achieving as much as 90% of theoretical density at room temperature; good sinterability, particularly with LiF which allows densification at least as low as 700C; and some creep plasticity especially with LiF during final densification that helped cope with tube elongation. Best results were obtained with MgO + LiF. Swaging at progressively increasing temperatures to 750C, firing at 1000C (in the sealed tube) resulted in essentially crack and inclusion free sections up to 98% of theoretical density. Further firing of the MgO in air to 1200C resulted in translucency (over 99% of theoretical density). (Author)

Descriptors :   (*SINTERING, *CERAMIC MATERIALS), POWDERS, MAGNESIUM COMPOUNDS, OXIDES, MECHANICAL WORKING, LITHIUM COMPOUNDS, FLUORIDES, DENSITY

Subject Categories : Ceramics, Refractories and Glass

Distribution Statement : APPROVED FOR PUBLIC RELEASE