Grain size << beam size

Transcription

1 Grain size << beam size Monochromatic beam microdiffraction - Texture analysis - Crystalline phases distribution - Mineralogical phase maps - Stress mapping Puerto Rico soil nodule

2 H(214) H(300) ALS, Berkeley Monochromatic 6 kev H(018) H(116) H(024) C(116) C(024) Q(211) C(113) H(113) C(110) H(110) C(104) H(104) Q(110) H(012) Diffraction pattern off the surface

3 H(300) H(214) Q(211) H(018) C(116) H(116) C(024) Corundum (C) : continuous lines very fine grain structure (nanocrystallised) H(024) C(113) H(113) C(110) H(110) C(104) H(104) H(012) Q(110) Hematite (H) : spotty lines μ-crystallized with subμm to 1 μm grain size Quartz (Q) : spots isolated peaks with large grain size ( 1μm)

4 Ph. Sciau et al. MRS proceedings (2004) Bright field TEM of the surface Electron Energy Loss (EELS)

5 Slip (or gloss) ) 20 μm 50 μm TSG50NA Body (or paste) Diffraction profiles fit with chemical analyses Hematite Anorthite Corundum body : Fe2O3 6.65%, CaO 12.56%, quartz, anorthite, traces of pyroxene slip : Fe2O %, CaO 1.37%, quartz, corundum Slip Position (mm) Body

6 Grain size << beam size Monochromatic beam microdiffraction - Texture analysis - Crystalline phases distribution - Mineralogical phase maps - Stress mapping Puerto Rico soil nodule Approx. of powder monochromatic diffraction : the sample is a large assembly of randomly oriented crystallites diffraction powder rings (grain size << beam size) The number of grains contributing to the diffraction pattern decreases with decreasing beam size (in the μm range) diffraction rings become spotty To a limit where monochromatic diffraction is no longer possible (grain size beam size)

7 Grain size << beam size Monochromatic beam microdiffraction - Texture analysis - Crystalline phase distribution - Mineralogical phase maps - Stress mapping Puerto Rico soil nodule Grain size > beam size Polychromatic (white) beam microdiffraction - Grain orientation mapping - Crystalline phase distribution - Strain/Stress mapping - Local plasticity - Dislocation densities La 0.95 Sr 0.05 Ga 0.90 Mg 0.10 O 3-x

8 C. Dejoie. Lauë BM32 ESRF surface Interface Images from the body Interface Fe fluorescence Out Slip Body

9 C. Dejoie. Lauë BM32 ESRF surface Interface body Interface Fe fluorescence Out Slip Body

10 White μ-beam XRD at the slip/body interface No quartz No corundum Hematite Spinel Spinel : grain 1 Reliability factor : 36 reflections are indexed as one single grain of spinel (out of 112 expected reflections)

11 Bright field image revealing the presence of needle-like spinel crystallites at the body/slip interface Ph. Sciau et al. J. of the American Society (2006)

12 Micro/Nano-structure of the clay surface PROPERTIES : 1) Different clays were used for surface and body 2) The glass matrix contains Al and Si (no metal) transparent 3) Sintered glass in dense and thick slip water proof 4) Colour is related with the presence of hematite small crystallites (larger hematite crystals turn black) 5) Presence of substituted Al in hematite contributes to the yellow tune 6) Presence of Quartz function of the washing/decanting process of the raw clay 7) Corundum nano-crystals contribute to the mechanical resistance 8) Corundum does not form in modern productions of Roman ware Level of MgO is lower in ancient potteries Firing techniques in oxidising conditions

13 Micro/Nano-structure of the clay surface PROPERTIES : 1) Different clays were used for surface and body 2) The glass matrix contains Al and Si (no metal) transparent 3) Sintered glass in dense and thick slip water proof 4) Colour is related with the presence of hematite small crystallites (larger hematite crystals turn black) 5) Presence of substituted Al in hematite contributes to the yellow tune 6) Presence of Quartz function of the washing/decanting process of the raw clay 7) Corundum nano-crystals contribute to the mechanical resistance 8) Corundum does not form in modern productions of Roman ware Level of MgO is lower in ancient potteries Firing techniques in oxidising conditions

14 Micro/Nano-structure of the clay surface PROPERTIES : 1) Different clays were used for surface and body 2) The glass matrix contains Al and Si (no metal) transparent 3) Sintered glass in dense and thick slip water proof 4) Colour is related with the presence of hematite small crystallites (larger hematite crystals turn black) 5) Presence of substituted Al in hematite contributes to the yellow tune 6) Presence of Quartz function of the washing/decanting process of the raw clay 7) Corundum nano-crystals contribute to the mechanical resistance 8) Corundum does not form in modern productions of Roman ware Level of MgO is lower in ancient potteries Firing techniques in oxidising conditions

15 Micro/Nano-structure of the clay surface PROPERTIES : 1) Different clays were used for surface and body 2) The glass matrix contains Al and Si (no metal) transparent 3) Sintered glass in dense and thick slip water proof 4) Colour is related with the presence of hematite small crystallites (larger hematite crystals turn black) 5) Presence of substituted Al in hematite contributes to the yellow tune 6) Presence of Quartz function of the washing/decanting process of the raw clay 7) Corundum nano-crystals contribute to the mechanical resistance 8) Corundum does not form in modern productions of Roman ware Level of MgO is lower in ancient potteries Firing techniques in oxidising conditions

16 Micro/Nano-structure of the clay surface PROPERTIES : 1) Different clays were used for surface and body 2) The glass matrix contains Al and Si (no metal) transparent 3) Sintered glass in dense and thick slip water proof 4) Colour is related with the presence of hematite small crystallites (larger hematite crystals turn black) 5) Presence of substituted Al in hematite contributes to the yellow tune 6) Presence of Quartz function of the washing/decanting process of the raw clay 7) Corundum nano-crystals contribute to the mechanical resistance 8) Corundum does not form in modern productions of Roman ware Level of MgO is lower in ancient potteries Firing techniques in oxidising conditions

17 Micro/Nano-structure of the clay surface PROPERTIES : 1) Different clays were used for surface and body 2) The glass matrix contains Al and Si (no metal) transparent 3) Sintered glass in dense and thick slip water proof 4) Colour is related with the presence of hematite small crystallites (larger hematite crystals turn black) 5) Presence of substituted Al in hematite contributes to the yellow tune 6) Presence of Quartz function of the washing/decanting process of the raw clay 7) Corundum nano-crystals contribute to the mechanical resistance 8) Corundum does not form in modern productions of Roman ware Level of MgO is lower in ancient potteries Firing techniques in oxidising conditions

18 Micro/Nano-structure of the clay surface PROPERTIES : 1) Different clays were used for surface and body 2) The glass matrix contains Al and Si (no metal) transparent 3) Sintered glass in dense and thick slip water proof 4) Colour is related with the presence of hematite small crystallites (larger hematite crystals turn black) 5) Presence of substituted Al in hematite contributes to the yellow tune 6) Presence of Quartz function of the washing/decanting process of the raw clay 7) Corundum nano-crystals contribute to the mechanical resistance 8) Corundum does not form in modern productions of Roman ware Level of MgO is lower in ancient potteries Firing techniques in oxidising conditions

19 Micro/Nano-structure of the clay surface PROPERTIES : 1) Different clays were used for surface and body 2) The glass matrix contains Al and Si (no metal) transparent 3) Sintered glass in dense and thick slip water proof 4) Colour is related with the presence of hematite small crystallites (larger hematite crystals turn black) 5) Presence of substituted Al in hematite contributes to the yellow tune 6) Presence of Quartz function of the washing/decanting process of the raw clay 7) Corundum nano-crystals contribute to the mechanical resistance 8) Corundum does not form in modern productions of Roman ware Level of MgO is lower in ancient potteries Firing techniques in oxidising conditions

20 Micro/Nano-structure of the clay surface PROPERTIES : 1) Different clays were used for surface and body 2) The glass matrix contains Al and Si (no metal) transparent 3) Sintered glass in dense and thick slip water proof 4) Colour is related with the presence of hematite small crystallites (larger hematite crystals turn black) 5) Presence of substituted Al in hematite contributes to the yellow tune 6) Presence of Quartz function of the washing/decanting process of the raw clay 7) Corundum nano-crystals contribute to the mechanical resistance 8) Corundum does not form in modern productions of Roman ware Level of MgO is lower in ancient potteries Firing techniques in oxidising conditions

21 SR-diffraction studies of ancient cosmetics

22 Lead white : a case study - Structure solving from powder data - Morphology of the crystallites synthesis? - Quantitative analysis recipes