Voltage Step Characteristics of Oxygen Concentration Cell Sensors for Nonequilibrium Gas Mixtures

1988 ◽  
Vol 135 (7) ◽  
pp. 1686-1691 ◽  
Author(s):  
Keiichi Saji ◽  
Haruyoshi Kondo ◽  
Takashi Takeuchi ◽  
Isemi Igarashi
Keyword(s):  
Oxygen Concentration ◽  
Gas Mixtures ◽  
Voltage Step ◽  
Concentration Cell ◽  
Nonequilibrium Gas

Structure And Stress Evaluation Of Diamond Films Deposited On Ti-6A1-4V Alloy At Low Temperature Using Ch4/O2/H2 And CO/H2 Gas Mixtures

1997 ◽  
Vol 505 ◽  
Author(s):  
Shane A. Catledge ◽  
Yogesh K. Vohra
Keyword(s):  
Low Temperature ◽  
Oxygen Concentration ◽  
Microwave Plasma ◽  
Diamond Films ◽  
Onset Time ◽  
Film Surface ◽  
Chemical Vapor ◽  
Gas Mixtures ◽  
Average Growth ◽  
Plasma Chemical Vapor Deposition

ABSTRACTLow temperature diamond deposition on metal substrates is motivated by the need to reduce thermal stress so that the film adhesion is satisfactory. Although the use of oxygen-con- taining gas mixtures have been shown to extend the temperature range for which diamond can grow as well as to improve film quality, most studies have focused on the use of silicon as sub- strates and have neglected technologically important metallic systems. To this end, microwave plasma chemical vapor deposition (MPCVD) was used to grow diamond films on Ti-6A1-4V alloy at low temperature (615 to 780 C) using CH4/O2/H2 and CO/H2 gas mixtures. In-situ pyrometric interferometry (ISPI) shows that as the oxygen concentration increases, the onset time for dia- mond nucleation and subsequent film surface roughness increases while the average growth rate decreases. Micro-Raman spectroscopy shows improved film quality and suggests a trend toward increasing in-plane compressive stress with increasing oxygen concentration. Glancing-angle x- ray diffraction (XRD) was complimentary to the Raman data and indicates the presence of a TiC interfacial layer thickness which decreases with increasing oxygen concentration. We found that the CO/H2 mixture resulted in poorly adhered “white soot” films with low diamond content whereas the CH4/O2/H2 mixture yielded well adhered high quality diamond films.

Effects of Salt Corrosion on the Adhesion of Brass Plated Steel Cord to Rubber

1986 ◽  
Vol 59 (1) ◽  
pp. 1-15 ◽  
Author(s):  
Yasuhiro Ishikawa ◽  
Shinji Kawakami
Keyword(s):  
Oxygen Concentration ◽  
Corrosion Test ◽  
Nacl Solution ◽  
Concentration Cell ◽  
Open Type ◽  
Salt Corrosion ◽  
Steel Cord ◽  
Brass Plating ◽  
Electrochemical Oxygen

Abstract Adhesion loss caused by salt corrosion is proposed to occur by the following process: 1) During a salt corrosion test, the NaCl solution rises in the cavity located at the steel-cord center. 2) An electrochemical oxygen concentration cell is formed. 3) OH− is produced by the reduction of oxygen. 4) An increase of the NaOH concentration causes the reverse of ion tendency between brass and steel. 5) Dezincification and dissolution of brass take place in the brass plating. The same process also occurs in the corrosion of a bare brass plated steel cord immersed in NaCl solution. Compounds containing cobalt stearate and a compound free from cobalt show adhesion deterioration by the process described above. Many other cobalt salts suppress the corrosion of brass in NaCl solution. At the same time, the underlying steel changes to become ignoble compared with brass, leading to the production of a large amount of rust. In view of the above considerations, it is desirable to remove the cavity located at the steel-cord center in order to suppress the steel-cord corrosion. Use of an open type of steel cord is useful in this respect.

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