Multilayer alloys

D. T. Schwartz, "Multilayered Alloys Induced by Fluctuating Flow," Journal of The Electrochemical Society, 136 (1989) 53C-56C. 

Summary of geometry of Cu 100 -c(2x2)-Pd(Pt) underlayer alloys determined by SATLEED. Positive values for buckling in layer 2 corresponds to adsorbate atoms relaxed towards the vacuum interface. Positive values for buckling in layer 4 corresponds to Cu atoms below Pd (or Pt) relaxed towards the adsorbate. The values in brackets below the interlayer spacings indicate the percentage contraction (negative) or expansion (positive) relative to the bulk value of Cu 100 of 1.807 A. The final entry corresponds to aPt multilayer alloy with a minimum of two ordered c(2x2) CuPt layers within the LEED probing depth. 

An ordered multilayer alloy is a surface alloy containing two (or more) ordered bimetallic layers within the selvedge. Two well characterised examples of ordered multilayer alloy formation have been reported to date. 

The case of Sn-Pt(lll) helps to understand the phenomena that occur in the interplay of the single-layer and the multilayer alloy formation. Other known cases are Au-Cu(lOO) [52] and Al-Ni(lOO) [54]. In other cases, such as Co-Pt(lll) [55], only the multilayer surface alloys have taken known to form. 

Cohen U, Koch FB, Sard R (1983) Electroplating of Cyclic Multilayered Alloy (CMA) coatings. J Electrochem Soc 130 1987-1995... 

Materials for MO Media. The materials classes best suited for MO media are RE-TM alloys, Co/Pt multilayers, and ferrites. The quality of disks is mainly characterised by the signal-to-noise ratio (SNR). 

Fig. 13. Expected signal and noise levels for RE-TM alloys and Pt/Co multilayers (schematic). The total noise entering the SNR is the sum of the system noise, disk noise, and write noise. The system noise is electronic noise and photon shot noise and is comparable for disks with the same reflectivity.

Multilayered composite sheets and plates can be bonded in a single explosion, and cladding of both sides of a backing metal can be achieved simultaneously. When two sides are clad, the two prime or clad metals need not be of the same thickness nor of the same metal or alloy. 

Electronic Applications. The PGMs have a number of important and diverse appHcations in the electronics industry (30). The most widely used are palladium and mthenium. Palladium or palladium—silver thick-film pastes are used in multilayer ceramic capacitors and conductor inks for hybrid integrated circuits (qv). In multilayer ceramic capacitors, the termination electrodes are silver or a silver-rich Pd—Ag alloy. The internal electrodes use a palladium-rich Pd—Ag alloy. Palladium salts are increasingly used to plate edge connectors and lead frames of semiconductors (qv), as a cost-effective alternative to gold. In 1994, 45% of total mthenium demand was for use in mthenium oxide resistor pastes (see Electrical connectors). 

Fig. 4. Multilayer coatings on cemented carbide substrates, (a) 73% WC—19%(Ta,Ti,Nb)C—8%Co alloy with a TiC—TiCN—TiN coating of about 10 )J.m total thickness, (b) 85%WC—9%(Ti,Ta,Nb)C—6%Co with a TiC—AI2O2—TiN coating about 9 lm thick, (c) 86%WC—8%(Ta,Ti,Nb)C—6%Co with TiCN...

Greer, A.L. and Somekh, R.E. (1991) Metallic multilayers, in Proce.ssing of Metals and Alloys, ed. Cahn, R.W. Materials Science and Technology A Comprehensive Treatment, vol. 15 (VCH, Weinheim) p. 329. 

Cu/Fee/Cu (right) (001) oriented multilayers when the substrate layer marked by an arrow is alloyed by Au. The Au concentration is varied between 0 (continuous line) and 100% (broken line). Only the Fe layers are numbered. 

Fig. 7.5 Simplified scheme for the diffusion-controlled growth of multilayered scales containing spinel layers on low-alloy steels...

The trend in CVD metallization is toward greater use of copper, and the refractory metals and their silicides in multilayered metallization designs, typically consisting of metal-silicide contacts, refractory-metal barriers, and copper or an aluminum alloy as the principal interconnect metal. Other metals deposited by CVD such as chromium, molybdenum, platinum, rhodium, and ruthenium are also actively considered for use as conductors. 

The alternate-multilayer formation in the alloy deposit can also be explained on the basis of the above mechanism. First, we have to note that thej value in the low-current... 

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