Abstract Armellinoite-(Ce), ideally Ca 4 Ce 4+ (AsO 4 ) 4 ⋅H 2 O, is a new mineral discovered in Fe–Mn ore in metaquartzites of the Montaldo mine, Corsaglia Valley, Cuneo Province, Piedmont, Italy. It occurs as very small and rare, pale yellow to brown–yellow pseudo-octahedral translucent crystals hosted by a matrix of quartz, hematite, cryptomelane/hollandite, tilasite, muscovite, braunite and montmorillonite. The mineral is translucent, with white streak and has a resinous to vitreous lustre. It is brittle with irregular fracture and fair cleavage parallel to {110} and {100}. Estimated Mohs hardness is ~3–3.5. Calculated density is 4.29 g⋅cm –3 . Armellinote-(Ce) is uniaxial (–), ω = 1.795(5), ɛ = 1.765(5) (white light), non-pleochroic and non-fluorescent. Chemical point analyses by WDS-EPMA yielded the empirical formula (based on 17 O+F anions): A (Ca 3.89 Th 0.08 Sr 0.02 La 0.03 ) Σ4.02 B (Ce 4+ 0.76 Nd 0.13 Y 0.08 Gd 0.03 Sm 0.02 Pr 0.01 Dy 0.01 Ho 0.01 ) Σ1.05 [(As 4.00 P 0.01 ) Σ4.01 O 4 ] 4 ⋅(H 2 O 0.85 F 0.15 ) Σ2.00 . The presence of H 2 O was confirmed by Raman spectroscopy. The mineral is tetragonal, I 4 1 / a , with single-crystal unit-cell parameters a = 10.749(2), c = 12.030(2) Å and V = 1390.0(6) Å 3 , with Z = 4. The eight strongest X-ray powder diffraction lines are [ d Å ( I rel ; hkl )]: 7.983 (36; 101), 4.443 (23; 2̄11), 2.957 (100; 3̄12), 2.398 (14; 420), 1.875 (22; 424, 325), 1.728 (19; 3̄16), 1.612 (13; 613) and 1.475 (26; 712, 552). The crystal structure ( R 1 = 0.0284 for 1275 unique reflections) has isolated T O 4 ( T = As 5+ ) tetrahedra that link Ca 2+ - or Ce 4+ -centred polyhedra via common oxygen ligands to form 2D blocks or double-layered (DL) structural units parallel to (001). Armellinoite-(Ce) is isostructural with pottsite, ideally (Pb 3 Bi)Bi(VO 4 ) 4 ⋅H 2 O, and closely related to a larger number of anhydrous synthetic compounds. The mineral is named after the mineral collector Gianluca Armellino (b. 1962), who collected the discovery sample.
Abstract Piccoliite, ideally NaCaMn 3+ 2 (AsO 4 ) 2 O(OH), is a new mineral discovered in the Fe–Mn ore hosted in metaquartzites of the Montaldo di Mondovì mine, Corsaglia Valley, Cuneo Province, Piedmont, Italy. It occurs as small and rare black crystals and aggregates hosted by a matrix of quartz, associated with calcite and berzeliite/manganberzeliite. It has been also found in the Valletta mine near Canosio, Maira Valley, Cuneo Province, Piedmont, Italy, where it occurs embedded in quartz associated with grandaite, hematite, tilasite/adelite and rarely thorianite. The mineral is opaque (thin splinters may be very dark red), with brown streak and has a resinous to vitreous lustre. It is brittle with irregular fracture. No cleavage has been observed. The measured Mohs hardness is ~5–5.5. Piccoliite is non fluorescent. The calculated density is 4.08 g⋅cm –3 . Chemical spot analyses by electron microprobe analysis using wavelength dispersive spectroscopy resulted in the empirical formula (based on 10 anions per formula unit) (Na 0.64 Ca 0.35 ) Σ0.99 (Ca 0.75 Na 0.24 ) Σ0.99 (Mn 3+ 1.08 Fe 3+ 0.59 Mg 0.20 Ca 0.10 ) Σ1.97 (As 2.03 V 0.03 Si 0.01 ) Σ2.07 O 9 (OH) and (Na 0.53 Ca 0.47 ) Σ1.00 (Ca 0.76 Na 0.23 Sr 0.01 ) Σ1.00 (Mn 3+ 0.63 Fe 3+ 0.49 Mg 0.48 Mn 4+ 0.34 Ca 0.06 ) Σ2.00 (As 1.97 P 0.01 Si 0.01 ) Σ1.99 O 9 (OH) for the Montaldo di Mondovì and Valletta samples, respectively. The mineral is orthorhombic, Pbcm , with single-crystal unit-cell parameters a = 8.8761(9), b = 7.5190(8), c = 11.689(1) Å and V = 780.1(1) Å 3 (Montaldo di Mondovì sample) and a = 8.8889(2), b = 7.5269(1), c = 11.6795(2) Å, V = 781.43(2) Å 3 (Valletta sample) with Z = 4. The seven strongest powder X-ray diffraction lines for the sample from Montaldo di Mondovì are [ d Å ( I rel ; hkl )]: 4.85 (57; 102), 3.470 (59; 120, 113), 3.167 (100; 022), 2.742 (30; 310, 213), 2.683 (53; 311, 023), 2.580 (50; 222, 114) and 2.325 (19; 320, 214, 223). The crystal structure ( R 1 = 0.0250 for 1554 unique reflections for the Montaldo di Mondovì sample and 0.0260 for 3242 unique reflections for the Valletta sample) has MnO 5 (OH) octahedra forming edge-shared dimers; these dimers are connected through corner-sharing, forming two-up-two-down [ [6] M 2 ( [4] T O 4 ) 4 φ 2 ] chains [ M = Mn; T = As; φ = O(OH)] running along [001]. These chains are bonded in the a and b directions by sharing corners with AsO 4 tetrahedra, giving rise to a framework of tetrahedra and octahedra hosting seven-coordinated Ca 2+ and Na + cations. The crystal structure of piccoliite is closely related to that of pilawite-(Y) as well as to carminite-group minerals that also show the same type of chains but with different linkage. The mineral is named after the mineral collectors Gian Paolo Piccoli and Gian Carlo Piccoli (father and son) (1926–1996 and b. 1953, respectively), the latter having discovered the type material at the Montaldo di Mondovì mine.
Abstract In anode‐supported solid oxide fuel cells (SOFCs), air break‐in on the anode side can result in reoxidation of metallic nickel. The volume expansion caused by Ni oxidation generates stresses within the substrate, the anode and the electrolyte. Those stresses exceed the stability of the components, potentially promoting crack growth. Therefore, either the SOFC degrades continuously after each redox‐cycle or the membrane electrode assembly (MEA) fails completely if the electrolyte cracks. The influence of several reoxidation parameters on the mechanical integrity of Ni–YSZ‐anodes after reoxidation was investigated using different types of samples. All samples were SFEs (substrate–functional layer–electrolytes), consisting of Ni–YSZ‐substrate, Ni–YSZ‐anode and YSZ‐electrolyte. Investigations were carried out on freestanding SFEs and SFEs attached to steel plates (Crofer22APU, Thyssen Krupp V. D. M., Material Data Sheet No. 4046 , Edition of December 2006) with a glass sealing. The results show a big influence of the degree of oxidation, homogeneity of oxidation, the operating temperature and the incident flow on the behaviour and the mechanical integrity of the reoxidised SFEs. The time of oxidation and the gas flow rate were influencing parameters, whereas the influence of the porosity was insignificant. The behaviour of the SFEs upon reoxidation also changes dramatically when comparing freestanding samples with attached samples.
'/%3e%3cpath id='b' d='M658.84 441.31c-7.618 16.446-22.845 19.271-36.164 5.995 0 0 5.354-3.783 11.086-4.826-1.075-4.574 1.13-10.902 4.235-14.324 3.258 2.227 7.804 6.689 8.96 11.874 8.03-1.04 11.883 1.282 11.883 1.282z'/%3e%3cuse xlink:href='%23b' transform='rotate(9.37 700 804)'/%3e%3cuse xlink:href='%23b' transform='rotate(18.74 700 804)'/%3e%3cpath fill='none' stroke='%23f8c300' stroke-width='16' d='M603 478a340 340 0 0 1 194 0'/%3e%3cg transform='translate(700 380)'%3e%3cg transform='translate(0 -140)'%3e%3cpath id='c' d='m0-513674 301930 929245-790463-574305h977066l-790463 574305z' transform='scale(.00005)'/%3e%3c/g%3e%3cg id='d'%3e%3cuse xlink:href='%23c' transform='translate(-70 -121.244)'/%3e%3cuse xlink:href='%23c' transform='translate(-121.244 -70)'/%3e%3cuse xlink:href='%23c' transform='translate(-140)'/%3e%3c/g%3e%3cuse xlink:href='%23d' transform='scale(-1 1)'/%3e%3c/g%3e%3c/g%3e%3c/svg%3e)
'%3e%3cpath fill='%23012169' d='M0 0v30h60V0z'/%3e%3cpath stroke='%23fff' stroke-width='6' d='m0 0 60 30m0-30L0 30'/%3e%3cpath stroke='%23C8102E' stroke-width='4' d='m0 0 60 30m0-30L0 30' clip-path='url(%23b)'/%3e%3cpath stroke='%23fff' stroke-width='10' d='M30 0v30M0 15h60'/%3e%3cpath stroke='%23C8102E' stroke-width='6' d='M30 0v30M0 15h60'/%3e%3c/g%3e%3c/svg%3e)
