| 摘要 |
<p>The invention concerns the treatment of diamonds in order to give them different colors and it can be made ise of by gem trade. The Essence of invention: The technique consists in producing isolated substitutional nitrogen atoms, or C centers in the crystal lattice of natural type Ia diamond containing A centers or of natural high-nitrogenous type Ia diamond containing over 800 ppm of nitrogen in the form of A and B1 centers. Natural type Ia diamonds containing A centers are annealed in a high-pressure apparatus at a temperature over 2150 DEG C under stabilizing pressure of 6.0-7.0 Gpa, then irradiated with 5x10<15>-5x10<18> cm<-2> 2-4 MeV electrons and finally annealed in vacuum at a temperature no lower than 1100 DEG C. Natural high-nitrogenous type Ia diamonds, containing over 800 ppm of nitrogen in the form of A and B1 centers, are irradiated with high-energy electrons with the irradiation dose over 10<19> cm<-2> and are annalead in vacuum at a temperature no lower than 1100 DEG C. Thus Fancy Red diamonds are produced with stable N-V cenetrs absorbing in the 400-to-640 nm range.</p> |
