Alpha counting measurement methods have been widely used in the semiconductor industry for many years to assess the suitability of materials for semiconductor production and packaging applications. Although a number of published articles describe aspects of this counting, a multicenter, comparative trial has not been carried out to assess the methodological accuracy of current methods. This paper reports on experience with a 9 center, international, round-robin style trial using a shared set of samples to quantify variability in alpha emission measurements. Four samples representing low and ultralow alpha materials were counted by each participating lab in a blinded trial. The consensus mean emissivity for low alpha material was estimated as 30.9 khr -1 -cm -2 with a range from 20.2 to 45.5, less than half of which can be attributed to counting uncertainty or other known sources of error. A strong correlation for replicate measurements within a lab was also observed supporting the conclusion that there are systematic variations in equipment or calibration among labs. Eleven of 23 measurements of ultralow alpha materials were within 1 standard deviation of the consensus mean and 7 were at or below background. The high level of counting uncertainty for these measurements is thought to be sufficient to mask any systematic variation similar to the low alpha observations. Comparison of the reported values with a standard calculation demonstrates that there are also differences in the interpretation of the values reported for emissivity and error, underscoring the need for careful interpretation of results.

Metal-supported solid oxide cells with P434L stainless steel support and BZCYYb-4411 electrode backbone and electrolyte layers are fabricated. Sintering aids for the ceramic layer are optimized. LiF is found to lower the ceramic sintering temperature too much. Manganese oxide enhances sintering and densification without dramatically reducing the sintering onset temperature. The impact of metal particle size on sintering is assessed. A symmetric structure helps to prevent warping or cracking arising from residual mis-match between the metal and ceramic sintering shrinkage. Intact cell structures are successfully prepared with <15 μm stainless steel particles and 2 wt% manganese oxide added to the BZCYYb-4411 layers.

No abstract

Metal-supported solid oxide electrolysis cells (MS-SOECs) with symmetric cell architecture were developed for high temperature electrolysis at Lawrence Berkeley National Laboratory (LBNL). The cell is comprised of a thin ceramic electrolyte and porous electrode backbones sandwiched between stainless steel metal supports. MS-SOECs offer a number of advantages over conventional all-ceramic SOECs due to their low-cost structural materials (e.g. stainless steel), mechanical ruggedness, excellent tolerance to redox cycling, and extremely fast start-up capability. The current density of MS-SOEC at 1.3 V and 50 vol% steam content is improved by optimizing microstructure of electrode backbone and procedure of catalyst infiltration. MS-SOEC with composite LSCF-SDC air electrode catalyst displays a degradation rate of 1.6%/100 h with current density of 0.33 A cm-2 at 700 °C in 1000 h test (Figure 1). Post-mortem analysis reveals that the degradation is caused by the primary modes of fuel electrode catalyst coarsening and Cr poisoning on air electrode catalyst, and secondary modes of metal support oxidation and local elemental accumulation of Ni. In an effort to suppress Cr migration thereby improving long term durability, advanced coatings, such as CoOx, NiFe2O4, (Co,Mn)3O4, etc., are applied to the cathode-side support by atomic layer deposition or electrodeposition. The impact of coating composition and deposition method will be reported. Figure 1. Durability of the cell with LSCF-SDC air electrode catalysts at constant current of 0.33 A cm-2 and 700 °C, with 50 vol% H2-50 vol% H2O. Figure 1

Ethylene is a large-scale commodity which is produced from fossil ethane via steam cracking. As more renewable electricity becomes available, electro-chemical production processes for ethylene are gaining attractiveness due to the generally high efficiency of electro-chemical processes and the potential to reduce CO2 emissions. In this study we explore the economics of oxidative coupling of methane (OCM)-based ethylene production and compare it to the conventional ethane steam cracking route. While current OCM cells are not economically competitive due to high capital investment costs (+105%) and high operating costs (+145%), OCM has the potential to become economically viable once overpotentials are lowered and single pass conversion rates reach +60%.