The infrared transmission of Pb0.1Ca0.9La2S4 pellets in the 2.5-14 mu m region

Highly sinterable submicron Pb0.1Ca0.9La2S4 (PCLS) powders were prepared by sulfidizing lead calcium and lanthanum alkoxides at 500 degrees C under CS 2 gas for 8 h and then in a pure H2S atmosphere for 16 h at 650-950 degrees C for application in an infrared transmitting window material for the 8-14 mu m wavelength region. The transmittance at 2.5 mu m of the pellet densif ied from the PCLS powder was 8 times higher than that from the beta-La2S3 p owder. The characteristic absorption bands of sulfite and sulfate at 9.2 an d 11 mu m, respectively, were reduced in the pellet by eliminating the oxyg en content in the PCLS powder by flowing chlorine gas into the furnace at 6 00 degrees C for 1 h and then sulfidizing the powder at 950 degrees C for 1 6 h. It was shown that 1100 degrees C was the optimum hot pressed sintering temperature for obtaining a higher transmittance ceramic.