Ⅱ Type A Industrial High Temperature And High Pressure Synthesis Of Diamond

The effects of the different content doped Ti on the “V” zone of the diamond, thecolor of the crystal, morphologyof diamond and nitrogen content inside the diamondwere systematically studied based on the solvent theory on diamond synthesis by meansof HTHP method as the guide using the domestic6surface high temperature and highpressure equipment, adopting the powder catalyst technologies in this paper.Researchwork done are as follows:the effects of different content Ti doped on diamond synthesisconditions were examined in Fe₇₀Ni₃₀+C system;the industrial transparent diamonds withlow nitrogen content were synthesized sussessfully by adding different proportion ofTi;the effects of the different content Ti doped on macro morphology and microstructurewere researched respectively through the optical microscope （OM） and scanningelectron microscopy （SEM）;the nitrogen content inside the synthesized diamond wasanalysized with microscopic infrared spectrum apparatus.Experimental results showedthat:（1） the diamond synthesis pressure and temperature change accordingly with theincrease of Ti content and the synthesis conditions rise first and then decrease in thedoped system;（2） the color of synthesis crystal is yellow without doping Ti content,and the color of synthesis crystal turns to transparent and colorless when0.5%Ticontent addition. The color of diamond synthesized are shallower in Ti content additionsystem than that in the raw crystals system with the increase of Ti content, thediamonds are colorless and the change of crystal color is not obvious;（3） the crystalshapes of synthesized diamonds are mainly hexahedral, and68side body without Ticontent addition. With the increase of Ti content, the shapes of diamond synthesized aremore than octagonal and crystal faces with high index such as {311} appear;（4） thesurfaces of diamonds synthesized are smooth and flat without Ti content doped; but with the increase of Ti content some irregular shapes of melting pit appear and thesurfaces of diamond are more rough;（5） with the increase of Ti content, crystalsbecome incomplete and completeness rate begin to decrease,polycrystalline and unitedcrystal phenomenon are obviously intense, and the inclusions inside the crystal appearto increase;（6）absorption peaks such as1282cm^-1,1185cm^-1,1130cm^-1and1344cm^-1are not found by adding Ti content in Fe₇₀Ni₃₀+C system, which can demonstrate thatnitrogen content inside syntheiszed diamond are easier to decline apparently than thatwithout Ti content addition; with the increase of Ti content, no ir spectrum line arefound without apparent change in the experimental result.