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PENGARUH VARIASI SUHU PROSES ELEKTROPLATING TEMBAGA MENGGUNAKAN LARUTAN CuSO₄ 0,5 M TERHADAP KETEBALAN LAPISAN, LAJU DEPOSISI, KEKASARAN PERMUKAAN DAN LAJU KOROSI PADA SUBSTRAT ALUMINIUM
Full text linkABSTRAK
Elektroplating Cu pada substrat Al merupakan salah satu teknik pelapisan yang banyak diterapkan untuk memperbaiki karakteristik permukaan material, baik dari sisi fisik maupun kimia. Penelitian ini bertujuan untuk mengkaji pengaruh variasi suhu proses elektroplating terhadap ketebalan lapisan, laju deposisi, kekasaran permukaan, serta laju korosi lapisan Cu yang dihasilkan. Proses pelapisan dilakukan menggunakan larutan elektrolit CuSO₄ dengan variasi suhu sebesar 30°C, 35°C, dan 40°C. Karakterisasi sifat fisik meliputi pengukuran ketebalan lapisan dan kekasaran permukaan, sedangkan sifat kimia dianalisis melalui perhitungan laju deposisi dan pengujian laju korosi menggunakan metode potensiodinamik dalam larutan 0,9% NaCl.
Hasil penelitian menunjukkan bahwa suhu elektroplating berpengaruh signifikan terhadap kinetika reaksi elektrokimia, laju difusi ion, serta mekanisme pertumbuhan lapisan Cu. Peningkatan suhu dari 30 °C hingga 40 °C menyebabkan ketebalan lapisan dan laju deposisi Cu meningkat, yang dikaitkan dengan bertambahnya energi kinetik ion Cu²⁺ sehingga mempercepat proses difusi dan reaksi reduksi pada permukaan katoda. Selain itu, kenaikan suhu juga menghasilkan penurunan nilai kekasaran permukaan, yang menandakan terbentuknya lapisan dengan morfologi yang lebih halus dan homogen akibat meningkatnya mobilitas atom selama proses pertumbuhan kristal.
Sebaliknya, laju korosi menunjukkan kecenderungan yang tidak linier terhadap variasi suhu elektroplating. Laju korosi terendah diperoleh pada suhu 35 °C, sementara pada suhu 40 °C laju korosi meningkat. Hal ini mengindikasikan bahwa laju deposisi yang terlalu tinggi berpotensi menimbulkan cacat mikro atau tegangan sisa pada lapisan. Dengan demikian, suhu 35 °C dapat dinyatakan sebagai kondisi optimum untuk menghasilkan lapisan Cu dengan keseimbangan sifat fisik dan ketahanan korosi yang baik.
Kata kunci: Elektroplating, Suhu, Tembaga (Cu), Aluminium (Al), Ketebalan Lapisan, Laju Deposisi, Kekasaran Permukaan, Laju Korosi.
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ABSTRACT
Copper electroplating on aluminum substrates is a widely used coating technique to improve surface characteristics, both in terms of physical and chemical properties. This study aims to investigate the effect of electroplating temperature variation on coating thickness, deposition rate, surface roughness, and corrosion rate of the resulting copper coatings. The electroplating process was carried out using a CuSO₄ electrolyte solution at temperatures of 30 °C, 35 °C, and 40 °C. Physical properties were characterized through measurements of coating thickness and surface roughness, while chemical properties were evaluated by calculating the deposition rate and determining the corrosion rate using the potentiodynamic polarization method in a 0.9% NaCl solution.
The results indicate that electroplating temperature has a significant influence on electrochemical reaction kinetics, ion diffusion rate, and the growth mechanism of copper coatings. Increasing the temperature from 30 °C to 40 °C led to an increase in both coating thickness and copper deposition rate, which is attributed to the enhanced kinetic energy of Cu²⁺ ions that accelerates diffusion and reduction reactions at the cathode surface. In addition, higher electroplating temperatures resulted in lower surface roughness values, indicating the formation of smoother and more homogeneous coatings due to increased atomic mobility during crystal growth.
In contrast, the corrosion rate exhibited a non-linear trend with respect to electroplating temperature. The lowest corrosion rate was observed at 35 °C, while a higher corrosion rate occurred at 40 °C. This behavior suggests that excessively high deposition rates may induce micro-defects or residual stresses within the coating. Therefore, an electroplating temperature of 35 °C can be considered the optimum condition for producing copper coatings with a balanced combination of improved physical properties and enhanced corrosion resistance.
Keywords: electroplating, temperature, copper (Cu), aluminum (Al), coating thickness, deposition rate, surface roughness, corrosion rat
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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