Electrical Contact Fabrication and Measurements of Metals and Alloys to Thermoelectric Materials

2007 ◽  
Vol 1044 ◽  
Author(s):  
Jonathan James D'Angelo ◽  
Edward J Timm ◽  
Fei Ren ◽  
Bradley D Hall ◽  
Eldon Case ◽  
...  
Keyword(s):  
Contact Resistance ◽  
Thermoelectric Materials ◽  
High Efficiency ◽  
Coefficient Of Thermal Expansion ◽  
Electrical Contact ◽  
Michigan State University ◽  
State University ◽  
Electrical Contact Resistance ◽  
Contact Data ◽  
P Type

AbstractLow electrical contact resistance is essential for the fabrication of high efficiency thermoelectric generators in order to convert heat to electricity. These contacts must be stable to high temperatures and through thermal cycling. A ratio of the contact resistance to the leg resistance below 0.1 is the goal for fabrication of a high efficiency thermoelectric power generation device. Here we present the fabrication procedures and characterization of contacts of metal alloys to Pb-Sb-Ag-Te (LAST) and Pb-Sb-Ag-Sn-Te (LASTT) compounds. Contacts were fabricated and measured for both ingot and hot pressed materials. Stainless steel 316 has shown a low resistance contact to these thermoelectric materials when the proper bonding conditions are used. Different time-temperature-pressure conditions for bonding to n-type and to p-type legs are presented. Contact resistances below 10μΩcm2 have been measured. In addition, break tests have shown bond strengths exceeding the semiconductor fracture strength. One of the considerations used in selecting iron alloys for electrical interconnects is the similarity in the coefficient of thermal expansion to the LAST and LASTT materials which is 18 ppm/°C and relatively temperature insensitive. Contacts to the thermoelectric materials were accomplished by diffusion bonding in a furnace developed in our lab at Michigan State University. The furnace is capable of reaching temperatures of up to 1000°C with a controlled atmosphere of a reducing gas. Fabrication procedures and contact data are presented in this paper.

Practical electrical contact resistance measurement method for bulk thermoelectric devices

2013 ◽  
Vol 1490 ◽  
pp. 153-159 ◽  
Author(s):  
Rahul P. Gupta ◽  
Robin McCarty ◽  
Jim Bierschenk ◽  
Jeff Sharp
Keyword(s):  
Contact Resistance ◽  
Thermoelectric Materials ◽  
Measurement Method ◽  
Electrical Contact ◽  
Device Performance ◽  
Metal Contacts ◽  
Electrical Contact Resistance ◽  
Industry Standard ◽  
Manufacturing Techniques ◽  
The Impact

ABSTRACTAs thermoelectric (TE) element length decreases, the impact of contact resistance on TE device performance grows more significant. In fact, for a TE device containing 100-μm tall Bi2Te3TE elements, the figure of merit ratio (ZTDevice/ZTMaterial) drops from 0.9 to 0.5 as the contact resistivity increases from 5 x 10-07 to 5 x 10-06 Ω-cm2. To understand the effects of contact resistance on bulk TE device performance, a reliable experimental measurement method is needed. There are many popular methods to extract contact resistance such as Transmission Line Measurements (TLM) and Kelvin Cross Bridge Resistor method (KCBR), but they are only well-suited for measuring metal contacts on thin films and do not necessarily translate to measuring contact resistance on bulk thermoelectric materials. The authors present a new measurement technique that precisely measures contact resistance (on the order of 5 x 10-07 Ω-cm2) on bulk thermoelectric materials by processing stacks of bulk, metal-coated TE wafers using TE industry standard processes. One advantage of this technique is that it exploits realistic TE device manufacturing techniques and results in an almost device-like structure, therefore representing a realistic value for electrical contact resistance in a bulk TE device. Contact resistance measurements for metal contacts to n- and p-type Bi2Te3 alloys are presented and an estimate of the accuracy of the measurements is discussed.

Discrete drops in the electrical contact resistance during nanoindentation of a bulk metallic glass

2016 ◽  
Vol 108 (18) ◽  
pp. 181903 ◽  
Author(s):  
Gaurav Singh ◽  
R. L. Narayan ◽  
A. M. Asiri ◽  
U. Ramamurty
Keyword(s):  
Metallic Glass ◽  
Contact Resistance ◽  
Bulk Metallic Glass ◽  
Electrical Contact ◽  
Electrical Contact Resistance

scholarly journals The Wear Process During the “Running-In” of Steel in Lubricated Sliding

1987 ◽  
Vol 109 (4) ◽  
pp. 587-591 ◽  
Author(s):  
M. Suzuki ◽  
K. C. Ludema
Keyword(s):  
Contact Resistance ◽  
Surface Film ◽  
Electrical Contact ◽  
Mineral Oil ◽  
Entrance Region ◽  
Engine Oil ◽  
Small Range ◽  
Electrical Contact Resistance ◽  
Metallic Contact ◽  
Wear Process

Steel cylinders were slid against flat steel disks, using a liquid lubricant, in order to study the progression of events associated with “running-in.” It was found that, when using mineral oil, the electrical contact resistance varied over a small range of high values indicating no metallic contact, whereas with engine oil a high resistance with an intermittent negligible contact resistance was found. A surface film forms from the additives in the engine oil which produces lower wear, slightly higher friction, a retarded running-in, and a rougher surface finish in the direction of sliding than does the mineral oil. A film which is composed only of Fe3O4 is formed when mineral oil is used. In addition, the mineral oil lubricated surfaces develop a conforming waviness across the sliding tracks. The oxide must have enhanced this surface conformity since it was not seen in the surfaces lubricated with engine oil. The role of the oxide may be further seen in experiments in which wear debris that accumulated in the entrance region of specimen contact was removed at frequent intervals. Little conforming waviness was seen in the latter case, suggesting that oxide which gathered in the entrance region abraded grooves in the steel surfaces. After the oxides were dislodged the friction increased and the contact resistance decreased for a time, indicating that the oxide acted like a solid lubricant.

Simultaneous Electrical and Thermal Modeling of a Contact-Type RF MEMS Switch

2003 ◽  
Author(s):  
Brian Jensen ◽  
Zhongde Wang ◽  
Kazuhiro Saitou ◽  
John L. Volakis ◽  
Katsuo Kurabayashi
Keyword(s):  
Contact Resistance ◽  
Direct Contact ◽  
Rf Mems ◽  
Bulk Material ◽  
Thermal Contact ◽  
Electrical Contact ◽  
Maximum Temperature ◽  
Electrical Contact Resistance ◽  
Rf Mems Switch ◽  
Mems Switch

Improving the power handling capability of direct contact RF MEMS switches requires a knowledge of conditions at the contact. This paper models the temperature rise in a direct contact RF MEMS switch, including the effects of electrical and thermal contact resistance. The maximum temperature in the beam is found to depend strongly on the power dissipation at the contact, with almost no contribution from dissipation due to currents in the rest of the switch. Moreover, the maximum temperature is found to exceed the limit for metal softening for a significant range of values of thermal and electrical contact resistance. Since local contact asperity temperature can be hundreds of degrees higher than the bulk material temperature modeled here, these results underscore the importance of understanding and controlling thermal and electrical contact resistance in the switch.

Failure mechanism in fiber-shaped electrodes for lithium-ion batteries

2015 ◽  
Vol 3 (20) ◽  
pp. 10942-10948 ◽  
Author(s):  
Wei Weng ◽  
Qingqing Wu ◽  
Qian Sun ◽  
Xin Fang ◽  
Guozhen Guan ◽  
...  
Keyword(s):  
Contact Resistance ◽  
Failure Mechanism ◽  
Electrical Contact ◽  
Active Material ◽  
Lithium Ion ◽  
Current Collector ◽  
Conductive Network ◽  
Electrical Contact Resistance ◽  
Loss Of Contact ◽  
First Time

Failure mechanism is investigated for the first time in a Si-based fiber-shaped electrode. The interphase electrical contact resistance indicates the dominant failure mechanism, which is the loss of contact between the current collector/conductive network and the active material. The decreasing contact resistance denotes the loose interphase contact and a decreasing capacity.

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