Wear of Electric Contact Surfaces

2007 ◽  
Author(s):  
J. Song
Keyword(s):  
Wear Resistance ◽  
Precious Metals ◽  
Electrical Contacts ◽  
Fretting Corrosion ◽  
Coating Materials ◽  
Long Term Stability ◽  
Electric Contacts ◽  
Contact Surfaces ◽  
Contact Shape

Fretting corrosion is one of the important factors which limits the lifetime of electric contacts. In order to avoid fretting corrosion coatings of different precious metals are used. The wear resistance of the coating determines the lifetime of electrical contacts. The long term characteristics of gold coated electrical contacts with different additives and contact shapes are investigated and the results are analyzed. It is found out that the wear resistance of contact coating can be largely influenced by the amount of the additive in gold and by the design of the contact shape. Only the combination of an optimized contact shape with suitable coating materials leads to a long term stability of electric contacts.

scholarly journals Study on Corrosion Resistance and Wear Resistance of Zn–Al–Mg/ZnO Composite Coating Prepared by Cold Spraying

Coatings ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 505
Author(s):  
Xinqiang Lu ◽  
Shouren Wang ◽  
Tianying Xiong ◽  
Daosheng Wen ◽  
Gaoqi Wang ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Composite Coatings ◽  
Salt Spray ◽  
Cold Spraying ◽  
Neutral Salt ◽  
Corrosion Resistant ◽  
Electrochemical Tests ◽  
Long Term Stability ◽  
Spray Technique

Two composite coatings, Zn65Al15Mg5ZnO15 and Zn45Al35Mg5ZnO15, were prepared by the cold spray technique and were found to be compact, with no pits or cracks, based on scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDS) investigations. The results of the neutral salt spray (NSS) and electrochemical tests showed that the two composite coatings possess a suitable corrosion performance. However, the Zn45Al35Mg5ZnO15 composite coatings were more corrosion resistant and allowed a better long-term stability. In addition, they were found to exhibit the best wear resistance and photocatalytic degradation efficiency.

Nanoscale Particles Enhanced Gold Plating

2011 ◽  
Vol 320 ◽  
pp. 210-215 ◽  
Author(s):  
Jian Song ◽  
Christian Koch ◽  
Liang Liang Wang ◽  
Srecko Stopic ◽  
Jelena Bogovic ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Gold Alloy ◽  
Precious Metals ◽  
Electrical Contacts ◽  
Gold Plating ◽  
Effective Measure ◽  
Nanoscale Particles ◽  
First Results ◽  
Considerable Impact ◽  
Gold Plates

Using precious metals as plating materials is an effective measure to avoid failures of electrical contacts caused by fretting. When using precious metals, such as gold, one of the limitations to their lifetime is the wear resistance. In order to improve the wear resistance of gold plates, gold alloy is usually used. Instead of alloying elements, nanoscale particles of metal oxides were used for the modification of plates in our investigation. Some of the nanoscale particles show considerable impact on the performance of plates for electrical contacts. This paper shows the first results and new challenges when using nanoscale particles for electroplating.

scholarly journals Correlation between Wear Resistance and Lifetime of Electrical Contacts

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Jian Song ◽  
Christian Koch ◽  
Liangliang Wang
Keyword(s):  
Electrical Conductivity ◽  
Wear Resistance ◽  
High Performance ◽  
Electrical Contacts ◽  
Electrical Performance ◽  
High Wear Resistance ◽  
High Electrical Conductivity ◽  
Fretting Corrosion ◽  
Long Lifetime

Electrical contacts are usually plated in order to prevent corrosion. Platings of detachable electrical contacts experience wear because of the motion between contacts. Once the protecting platings have been worn out, electrical contacts will fail rapidly due to corrosion or fretting corrosion. Therefore the wear resistance of the platings is a very important parameter for the long lifetime of electrical contacts. Many measures which improve the wear resistance can diminish the conductivity of the platings. Due to the fact that platings of electrical contacts must have both a high wear resistance and a high electrical conductivity, the manufacturing of high performance platings of electrical contacts poses a great challenge. Our study shows firstly the correlation between the wear resistance of platings and lifetime of electrical contacts and then the measures, which improve the wear resistance without impairing the electrical performance of the contacts.

New Trim Configurations for Laser Trimmed Thick-Film Resistors – Experimental Verification

2005 ◽  
Vol 2 (1) ◽  
pp. 19-24 ◽  
Author(s):  
Slawomir Kaminski ◽  
Edward Mis ◽  
Maciej Szymendera ◽  
Andrzej Dziedzic
Keyword(s):  
Thick Film ◽  
Experimental Verification ◽  
Electrical Potential ◽  
Low Frequency ◽  
Frequency Noise ◽  
New Approach ◽  
Long Term Stability ◽  
Pathway Length ◽  
Contact Shape

Laser trimming is the most effective and popular trimming method of thick-film and LTCC resistors at present. It is also still a subject of continuing theoretical and experimental analysis and optimization. Very recently a new approach to this process was suggested. It consists in replacing two-contact bar resistors by three-contact distributed structures trimmed by narrow cuts just around additional contact of different shape [1,2]. This paper presents experimental verification of such an approach. The relative trim characteristic and sensitivity are analyzed as a function of additional contact shape and cut length. Next long-term stability, pulse durability and low frequency noise are compared for two- and three-contact resistors versus trim pathway length. These investigations are completed by simulation of electrical potential distribution in two- and three-contact resistors with various length of trimming kerf.

Stability and Change in Emotional Intelligence: Exploring the Transition to Young Adulthood

2005 ◽  
Vol 26 (2) ◽  
pp. 100-106 ◽  
Author(s):  
James D.A. Parker ◽  
Donald H. Saklofske ◽  
Laura M. Wood ◽  
Jennifer M. Eastabrook ◽  
Robyn N. Taylor
Keyword(s):  
High School ◽  
Emotional Intelligence ◽  
Postsecondary Education ◽  
Life Transition ◽  
Full Time ◽  
Major Life ◽  
Long Term Stability ◽  
Time Period ◽  
Transition From High School

Abstract. The concept of emotional intelligence (EI) has attracted growing interest from researchers working in various fields. The present study examined the long-term stability (32 months) of EI-related abilities over the course of a major life transition (the transition from high school to university). During the first week of full-time study, a large group of undergraduates completed the EQ-i:Short; 32 months later a random subset of these students (N = 238), who had started their postsecondary education within 24 months of graduating from high school, completed the measures for a second time. The study found EI scores to be relatively stable over the 32-month time period. EI scores were also found to be significantly higher at Time 2; the overall pattern of change in EI-levels was more than can be attributed to the increased age of the participants.

Multi-Center Calibration of the Second Reference Material for Thromboplastin, Rabbit, Plain, Coded CRM 149R

1991 ◽  
Vol 65 (03) ◽  
pp. 263-267 ◽  
Author(s):  
A M H P van den Besselaar ◽  
R M Bertina
Keyword(s):  
Reference Material ◽  
Standard Error ◽  
Standard Errors ◽  
Sensitivity Index ◽  
Long Term Stability ◽  
Significant Bias ◽  
The Mean ◽  
The Relationship ◽  
International Sensitivity Index

SummaryIn a collaborative trial of eleven laboratories which was performed mainly within the framework of the European Community Bureau of Reference (BCR), a second reference material for thromboplastin, rabbit, plain, was calibrated against its predecessor RBT/79. This second reference material (coded CRM 149R) has a mean International Sensitivity Index (ISI) of 1.343 with a standard error of the mean of 0.035. The standard error of the ISI was determined by combination of the standard errors of the ISI of RBT/79 and the slope of the calibration line in this trial.The BCR reference material for thromboplastin, human, plain (coded BCT/099) was also included in this trial for assessment of the long-term stability of the relationship with RBT/79. The results indicated that this relationship has not changed over a period of 8 years. The interlaboratory variation of the slope of the relationship between CRM 149R and RBT/79 was significantly lower than the variation of the slope of the relationship between BCT/099 and RBT/79. In addition to the manual technique, a semi-automatic coagulometer according to Schnitger & Gross was used to determine prothrombin times with CRM 149R. The mean ISI of CRM 149R was not affected by replacement of the manual technique by this particular coagulometer.Two lyophilized plasmas were included in this trial. The mean slope of relationship between RBT/79 and CRM 149R based on the two lyophilized plasmas was the same as the corresponding slope based on fresh plasmas. Tlowever, the mean slope of relationship between RBT/79 and BCT/099 based on the two lyophilized plasmas was 4.9% higher than the mean slope based on fresh plasmas. Thus, the use of these lyophilized plasmas induced a small but significant bias in the slope of relationship between these thromboplastins of different species.

The Stability of the WHO Reference Thromboplastin NIBS & C 67/40

1979 ◽  
Vol 42 (04) ◽  
pp. 1135-1140 ◽  
Author(s):  
G I C Ingram
Keyword(s):  
Human Brain ◽  
Collaborative Study ◽  
Calibration Constant ◽  
Long Term Stability ◽  
Freeze Dried ◽  
Show Evidence ◽  
Human Material ◽  
Reference Preparation ◽  
The Stability

SummaryThe International Reference Preparation of human brain thromboplastin coded 67/40 has been thought to show evidence of instability. The evidence is discussed and is not thought to be strong; but it is suggested that it would be wise to replace 67/40 with a new preparation of human brain, both for this reason and because 67/40 is in a form (like Thrombotest) in which few workers seem to use human brain. A �plain� preparation would be more appropriate; and a freeze-dried sample of BCT is recommended as the successor preparation. The opportunity should be taken also to replace the corresponding ox and rabbit preparations. In the collaborative study which would be required it would then be desirable to test in parallel the three old and the three new preparations. The relative sensitivities of the old preparations could be compared with those found in earlier studies to obtain further evidence on the stability of 67/40; if stability were confirmed, the new preparations should be calibrated against it, but if not, the new human material should receive a calibration constant of 1.0 and the new ox and rabbit materials calibrated against that.The types of evidence available for monitoring the long-term stability of a thromboplastin are discussed.

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