Title:
TUNGSTEN FILAMENT, WHICH IS HARDLY SAGGED, AND LAMP USING SAID FILAMENT
Document Type and Number:
Japanese Patent JPH04249852
Kind Code:
A
Abstract:
PURPOSE: To improve strength under high temperatures and resistance to sagging by forming a filament structure into a microstructure consisting of a slender grain engaged and combined with each other which is regulated according to a grain shape parameter having a value of about 10 or more. CONSTITUTION: A double coil filament is formed by winding a tungsten filament wire having nearly 0% recrystallization around a primary and a secondary mandrel composed of molybdenum and steel. After annealing is applied thereto so as to control an elastic spring back, the double coil filament is taken out from the secondary mandrel and immersed into an acid bath to thereby dessolve the other mandrel. Thereafter, a recrystallization treatment is carried out to perform heating under the absolute temperature of 2650 deg. K for 30 seconds, then quenching is done up to a room temperature. Hereby, a grain shape parameter(GSP) having 10 or more is obtained. Further, a value of GSP is equal to one such that grain axis ratio(GAR) is divided by grain boundary factor(GBF) and it can be specified measured in a stated procedure with using a electron microscope.
Inventors:
JIYON UIRIAMU PIYUU
DONARUDO RII BURAI
DONARUDO RII BURAI
Application Number:
JP13033091A
Publication Date:
September 04, 1992
Filing Date:
May 07, 1991
Export Citation:
Assignee:
GEN ELECTRIC
International Classes:
G02B5/28; H01K1/08; H01K7/00; C22C27/04; (IPC1-7): C22C27/04; G02B5/28; H01K1/08; H01K1/32; H01K7/00
Domestic Patent References:
| JPS50100879A | 1975-08-09 | |||
| JPS5782961A | 1982-05-24 | |||
| JPS4970811A | 1974-07-09 |
Attorney, Agent or Firm:
Tokunji Ikunuma