Sulfide partial melting and galena–tetrahedrite intergrowth texture: An experimental study

Galena–tetrahedrite intergrowth textures have been observed in some quenched run products of melting experiments conducted at 500 and 600°C in the systems ZnS–PbS–FeS–Cu2S–Sb2S3 and ZnS–PbS–FeS–Cu2S–Sb2S3–As2S3, using the evacuated silica-tube method. At 600°C the intergrowth formed an interface between sulfide melt and galena, whereas at 500°C it existed as inclusions partially embedded or completely embedded within tetrahedrite. At 600°C tetrahedrite was absent in PbS-bearing experiments, instead galena and melt were a part of the equilibrium phase assemblage. From the disposition of the galena–tetrahedrite intergrowths at 500°C it is evident that droplets of galena–tetrahedrite melt coexisted with tetrahedrite or tetrahedrite + galena and gave rise to these intergrowths upon quenching. The intergrowths coexisting with galena probably represent compositions on the galena-rich liquidus in the galena–tetrahedrite binary and those coexisting with tetrahedrite represent points on the tetrahedrite-rich liquidus. A eutectic at galena:tetrahedrite = ~30:70, very close to 500°C is apparent. It is clearly indicated that galena–tetrahedrite intergrowths can be formed by sulfide partial melting, and could be used as a potential indicator of partial melting in metamorphosed sulfide ore deposits.

Silicone Rubber Based Highly Sensitive Fiber-Optic Fabry–Perot Interferometric Gas Pressure Sensor

A simple, compact, and highly sensitive gas pressure sensor based on a Fabry–Perot interferometer (FPI) with a silicone rubber (SR) diaphragm is demonstrated. The SR diaphragm is fabricated on the tip of a silica tube using capillary action followed by spin coating. This process ensures uniformity of its inner surface along with reproducibility. A segment of single mode fiber (SMF) inserted into this tube forms the FPI which produces an interference pattern with good contrast. The sensor exhibits a high gas pressure sensitivity of −0.68 nm/kPa along with a low temperature cross-sensitivity of ≈ 1.1 kPa/°C.

Structure and magnetic properties of Sm2Rh3Sn5 – an intergrowth of TiNiSi- and NdRh2Sn4-related slabs

The stannide Sm2Rh3Sn5 was obtained by arc-melting of the elements and subsequent annealing at 1070 K in a silica tube. Sm2Rh3Sn5 crystallizes with the orthorhombic Y2Rh3Sn5 type structure, space group Cmc21, Z=4: a=444.46(8), b=2636.2(4), c=718.3(1) pm, wR=0.0711, 1761 F2 values and 61 variables. The three crystallographically independent rhodium atoms show tricapped trigonal prismatic coordination by samarium and tin atoms. Sm2Rh3Sn5 can be considered as a simple 1:1 intergrowth structure of TiNiSi- and NdRh2Sn4-related slabs of compositions SmRhSn and SmRh2Sn4. Temperature dependent magnetic susceptibility data revealed van Vleck type behavior caused by the proximity of the exited 6H7/2 state to the 6H5/2 ground state of Sm3+, and an antiferromagnetic ordering occurs at TN=3.5(5) K.