| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a large and inexpensive pressure resistant window causing no problem of cleavage cracking unlike conventional single-crystalline diamond, and highly resistant and tough against X-ray or infrared light. <P>SOLUTION: The pressure resistant window is formed of polycrystalline diamond. The polycrystalline diamond substantially comprises only diamond and is obtained by sintering and converting a raw material composition containing non-diamond type carbonaceous substance directly to diamond without addition of a sintering assistant and a catalyst at an ultra-high temperature. The polycrystalline diamond has a mixed composition of fine-grained diamond crystal with a maximum particle size of 100 nm or less and an average particle size of 50 nm or less, with plate-like or granular coarse-grained diamond crystal with a particle size of 50-10,000 nm. <P>COPYRIGHT: (C)2008,JPO&INPIT |
