Further study of the difference in nitrogen aggregation among (111) and (100) growth sectors of synthetic diamonds

Satoh, Shuichi; Nakashima, T.; Tsuji, K.; Yazu, S.

doi:10.1080/08957959008246301

Cited by 8 publications

(15 citation statements)

References 2 publications

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“…Thus the gradual changes within zones B, C and D of the 'wildone' noted above are terminated by sharp changes in CL luminescence, Npp m and the change of growth zone orientation from cuboid to octahedral. It is difficult to say whether these abrupt changes reflect straightforward changes in the fluid reservoir from which the diamonds grew, or whether they also reflect changes in growth rate and uptake of N in the cuboid to octahedral transition (Lang, 1974a;Sunagawa, 1984;Burns et al, 1990;Satoh et al, 1990;Taylor et al, 1996).…”

Section: N and ~T3c In Relation To Growth Historymentioning

confidence: 99%

Carbon isotope ratios and nitrogen abundances in relation to cathodoluminescence characteristics for some diamonds from the Kaapvaal Province, S. Africa

et al. 1999

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Secondary ion mass spectrometry (SIMS) techniques have been used to study the variation of C isotope ratio and N abundance within selected diamonds in relation to their crystal growth zones. The growth zones are seen in cathodoluminescence (CL), and include both octahedral and cuboid zones within typical diamonds of external octahedral morphology. Compositions were determined by use of a primary 133Cs + ion beam and measurement of 12C-, 13C , and 12C14N-secondary ions at high mass resolution on a Cameca ims-4f ion microprobe at Edinburgh University.In each of the diamonds, different growth zones have marked differences in N abundance, which are as great as 0-1400 ppm within one diamond. Changes of several hundred ppm N are common across both octahedral and cuboid growth zones, and appear sharp and abrupt at the boundaries of the growth zones. In general for the common blue CL, luminescence increases with N abundance. The changes in N abundance across fine scale (-100 gm) growth zones show that the total N contents determined byIR spectroscopy may show great varmtlons of abundance. In contrast, w~thm detection hm ts, 8 C appears constant across many growth zone boundaries. Thus the factors controlling uptake of N from the fluid/melt reservoir in which natural diamonds grow often do not influence 813C. No evidence of progressive variation or fractionation of C isotopes during growth was found. Some original variation in C isotope composition may have been eliminated by diffusion of C atoms subsequent to growth, because of the storage of natural diamonds over millions of years in the Earth's mantle at temperatures of 950-1250~ Such atomic mobility does not homogenize N distribution because of the proven tendency of N to form aggregates of atoms. A survey of experimental estimates of single atom (C) diffusion parameters, suggests that diffusion distances of-100 pm are likely at high temperatures (-1100~ over long time periods (~1.0 Ga). Therefore, with refinement of the diffusion parameters and measurements, the extent of C isotope homogenization in natural diamonds, as well as N aggregation state, might provide quantitative evidence of their time-temperature history under mantle conditions.

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Section: N and ~T3c In Relation To Growth Historymentioning

confidence: 99%

Carbon isotope ratios and nitrogen abundances in relation to cathodoluminescence characteristics for some diamonds from the Kaapvaal Province, S. Africa

et al. 1999

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“…14.18, a growth-sector dependence is clearly seen. Usually, the depth of the yellow color caused by nitrogen is in the order of {111} > {001} > {011} = {113} [79], although the order is the reverse in crystals grown at the lowest temperatures, namely, {001} > {111} [47]. The Ni-related colors are seen only in {111} sectors [80].…”

Section: Effect Of the Metal Solvent/catalystsmentioning

confidence: 99%

“…Early papers noted that colorless crystals are synthesized at higher temperature, whereas lower growth temperatures give a yellow color [53]. Precise control of the growth temperature confirmed the nitrogen concentration gradually decreases with increasing growth temperature [47].…”

Section: Effect Of Growth Temperaturementioning

confidence: 99%

“…The rate constant, k, is 1.9 × 10 −5 min −1 ppm −1 , which gives 50 % conversion of 500 ppm of isolated nitrogens to the pairs by 2 h heating at 1600 • C [91], although Evans and Qi [92] gave a one order lower value of the constant. Other reports suggest the aggregation rate may depend on radiation damage and growth conditions of a crystal and location in a crystal [47,93,94].…”

Section: Color Change With Heat Treatmentmentioning

confidence: 99%

“…There are reports that {100} are more dominantly grown at a lowertemperature condition, while {111} are dominant at high temperatures[47].Minor surfaces such as {113} and {011} commonly appear in addition to {111} and {001}. {115} surfaces have also been reported to appear, although they are much less common[41,48,49].…”

mentioning

confidence: 99%

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