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Start Over Author "Reddy, Aparna" Topic surfaces, coatings and films
4 results on '"Reddy, Aparna"'

1. Novel interface modification technique applied from the top of a coated layer

Author

Yarrama-Reddy Aparna, Kazuhiro Yoshihara, and Michiko Yoshitake

Subjects
Materials science, Diffusion, Metallurgy, Intermetallic, Niobium, chemistry.chemical_element, Surfaces and Interfaces, Substrate (printing), engineering.material, Condensed Matter Physics, Surfaces, Coatings and Films, Metal, Coating, chemistry, visual_art, engineering, visual_art.visual_art_medium, Composite material, Layer (electronics), Titanium
Abstract

A technique to modify the interface after the formation of the interface is needed either because of some process requirement or because of a change in the required material function over time. In this article we present a novel technique to form an intermetallic compound at the interface between a coating layer and the substrate by depositing a specific metal film on the top of a coating layer. Based on the property of the intermetallic compound, the interface is modified. Experimentally, the diffusion and interfacial reaction of specimens with a top-film/middle-film/substrate structure were investigated. With proper choice of the top-film metal, the top-film metal diffuses inward without any significant reaction with the middle film and concentrates at the interface between the middle film and the substrate followed by formation of an intermetallic compound. We discuss conditions for obtaining the above phenomena and present a general guide for choosing the top-film metal. Key factors are (1) the segreg...

Published
2001

2. General rule for predicting surface segregation of substrate metal on film surface

Author

Kazuhiro Yoshihara, Yarrama-Reddy Aparna, and Michiko Yoshitake

Subjects
Auger electron spectroscopy, Materials science, Analytical chemistry, Surfaces and Interfaces, Substrate (electronics), Condensed Matter Physics, Surface energy, Surfaces, Coatings and Films, Metal, Adsorption, X-ray photoelectron spectroscopy, visual_art, Etching, visual_art.visual_art_medium, Crystallite
Abstract

We studied surface segregation of substrate metal on the top of a deposited film in a vacuum. A metallic polycrystalline film of submicron or micrometer thickness was deposited on a substrate and heated in an Auger electron spectroscopy (AES) or x-ray photoelectron spectroscopy (XPS) apparatus. The surface composition was monitored during heating. The specimen was heated until the substrate metal was observed on the surface of the deposited film and the surface concentration of the substrate metal became saturated. The depth profile of the heated specimen was obtained by measuring AES/XPS with Ar ion etching. Al, Ti, Cr, Ni, Cu, Nb, and Fe were used as substrate materials and Al, Ti, Cr, Cu, Zr, Nb, and Fe were used as film materials. More than 25 combinations of film–substrate materials have been investigated. For some film–substrate combinations, substrate metal was observed on the surface by heating at rather low temperature and substrate metal was only observed at the surface (i.e., surface segregatio...

Published
2001

3. Modification of Coating Layer/Base Material Interface by Utilizing Interfacial Segregation Phenemona

Author

Kazuhiro Yoshihara, Yarrama-Reddy Aparna, and Michiko Yoshitake

Subjects
Materials science, Diffusion, Metallurgy, Intermetallic, Activation energy, Substrate (printing), engineering.material, Condensed Matter Physics, Surfaces, Coatings and Films, Metal, Coating, visual_art, visual_art.visual_art_medium, engineering, Electrical and Electronic Engineering, Composite material, Layer (electronics), Phase diagram
Abstract

A technique to modify interface after the formation of interface is desired either from a process requirement or because of the change of material use with time. A novel technique to form an intermetallic compound at the interface between coated layer and substrate by depositing a chosen metal film on the top of a coated layer is presented. The diffusion and interfacial reaction of specimens with top-film/middle-film/substrate structure were investigated. With proper choice of top-film element, top-film element diffused inside without detectable reaction with middle-film and concentrated at the interface between middle-film and substrate followed by intermetallic compound formation. We discuss conditions for obtaining above phenomena and general guide for a choice of top-film element is presented. Key factors are (1) segregation tendency of top-film element on middle-film metal, (2) activation energy of diffusion of top-film element in middle-film and in substrate, and (3) existence of intermetallic compound between top-film metal and substrate in phase diagram. The examples of intermetallic compound formation by the diffusion of top-film element are given in Ti-film/Nb-film/Cu-substrate, Fe-film/Nb-film/Ti-substrate, Cu-film/Fe-film/Zr-substrate, and Fe-film/Zr-film/Ti-substrate.

Published
2001

4. [Untitled]

Author

Michiru NISHIWAKI, Akihiro YAMAMOTO, Shigeki KATO, Yusuke SUETSUGU, Susumu KATO, Hirohisa TAKAHASHI, Tatsuo ASAMAKI, Mina YAGIHARA, Takashi ADACHI, Takao SEKI, Akio ABE, Hiroto KURIYAMA, Takato HIRAYAMA, Ichiro ARAKAWA, Teronobu MIYAZAKI, Naoto KIKUCHI, Yoshihiro SAWAHIRA, Eiji KUSANO, Hidehito NANTO, Akira KINBARA, Makoto MATSUI, Yukio INOKUTI, Kazuhiro SUZUKI, Michimasa KIKUCHI, Toshiyuki HIGASHINO, Katsuto TANAHASHI, Jiro OSAKA, Yuichi KAWAMURA, Naohisa INOUE, Yoshikazu HOMMA, Kunio TAKAYANAGI, Masahiro HIRATA, Nobuhiko OTA, Shinji SHINABE, Yuto FUKUMA, Yoshiro SHIOKAWA, Masakazu ICHIKAWA, Ken-ichi KANAZAWA, Hiromi HISAMATSU, Masayuki SHIMAMOTO, Masayuki SATO, Mitsuru SHIRAI, Osamu KONNO, Yuuki WATANABE, Shinichi KOBAYASHI, Yoshio SAITO, Kentarou SEKIKAWA, Kiyomitsu ASANO, Hiroki ASARI, Hideharu MATSUSHIMA, Hiroshi MIMA, Kazutugu MURAKAMI, Atushi KAWAHARA, Toshio MASUOKA, Soichi OGAWA, Shigemi SUGINUMA, S.S. HONG, K.H. CHUNG, Kouichi HAMADA, Masaki HESAKA, Hiroki KURISU, Setuo YAMAMOTO, Mituru MATSUURA, Yasunori YANAGISAWA, Akira KASAHARA, Masatoshi TOSA, Young-Sung Kim, Kazuhiro YOSHIHARA, Yuden TERAOKA, Akitaka YOSHIGOE, Mutsumi SANO, Hiroko KAJI, Kiminori KAKITANI, Yoichiro YAGI, Akio YOSHIMORI, Hiroshi TSUJI, Hitoshi SASAKI, Hiroko SATO, Yasuhito GOTOH, Junzo ISHIKAWA, Shunsuke KIDO, Michiko YOSHITAKE, Yarrama-Reddy APARNA, Hiroaki TANAKA, Kimio OKUNO, Minoru NAGAI, Masahiko TOMITORI, Kaoru ABE, Takayuki TSUGUEDA, Kazuya SAITO, Masamichi MATSUURA, Toshiyuki OHYA, Hiroyuki NAGAHAMA, Tetsuo SHIMOMURA, Seiichiroh YOKOYAMA, Masahiko MITSUHASHI, Seishiro OHYA, Kotaro SHINOHARA, Ichiro SENBA, Kunio OKIMURA, Tomohiro ARAKAWA, Hideaki TAKEZAWA, Tadashi NAKAMURA, Chikanori INO, Yasuhiro ARAKI, Yasuhiro IGASAKI, Nobuo SAITO, Isamu NAKAAKI, Hiromu IWATA, Sigeaki NAKAMURA, Shoji YOSHIOKA, Tomuo YAMAGUCHI, Ryuta AI, Kiyotaka WASA, Yoshiki MORIKAWA, Tetsuya NISHIGUCHI, Masaharu MIYAMOTO, Shingo ICHIMURA, Hidehiko NONAKA, Masakuni KAWADA, Hiroshi MURAKAMI, Hideo HASEGAWA, Ayako HIOKI, Kazuki NATSUKAWA, Shinichi NISHIZAWA, Kazuo MACHIDA, Akiko N. ITAKURA, Tetsuya NARUSHIMA, Masahiro KITAJIMA, Ruediger BERGER, Christoph GERBER, James K. GIMZEWSKI, Tetsu MIENO, Hiroaki ITO, Hiroki KAWADA, Miyuki YAMANE, Hiroyuki KITSUNAI, Nobuo TSUMAKI, Manabu YAMASHITA, Shinichi SUZUKI, Yoshitaka NAITOH, Yoshifumi OHSHIMA, Hiroyuki HIRAYAMA, Ken-ichi TANAKA, Masamichi IKAI, Shigehiko YAMAMOTO, Toru KANAJI, Takashi MORII, Masatomo NISHIURA, Makoto TANAKA, Yukio Yasuda, Hiroya Ikeda, Shigeaki Zaima, Yasuo KIMURA, Daisei SHOJI, Masanori SHINOHARA, Michio NIWANO, Takeshi KITAHARA, Hideki TANAKA, Hiroyuki WAKIMOTO, Goro MIZUTANI, Sukekatsu USHIODA, Koichiro MITSUKE, Makoto SAKURAI, Sin-ichi IGARASHI, Aki TOSAKA, Daisuke IGUCHI, Tomomi HIRAOKA, Shinjiro YAGYU, Takahiro KONDO, Toshiyuki IKEUCHI, Da-ling Lu, Takayoshi SAITOH, Suguru SAIKI, Kazuhiro FUKUSHIMA, Shigeru MIZUNO, Shin-ichiro TAGUCHI, Hideki SATO, Masao SASAKI, Makoto SATO, Yukito NAKAGAWA, K.Hassan Bhuiyan, Hideaki Inoue, Yoshikazu TAKAHASHI, Yoshihiro IKEDA, Masato KIUCHI, Takaomi MATSUTANI, Takae TAKEUCHI, Takashi MATSUMOTO, Kazuhiko MIMOTO, and Seiichi GOTO

Subjects
Electrical and Electronic Engineering, Condensed Matter Physics, Surfaces, Coatings and Films
Published
2000

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