Temat: proces modyfikacji - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Friction stir processing - analysis of the process
Tarciowa modyfikacja warstw wierzchnich z mieszaniem materiału - analiza procesu
Autorzy:: Węglowski, M. S.
Pietras, A.
Powiązania:: https://bibliotekanauki.pl/articles/351577.pdf
Data publikacji:: 2011
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: proces tarciowej modyfikacji warstw wierzchnich z mieszaniem materiału
stopy aluminium
moment obrotowy wrzeciona
friction stir processing
aluminium alloy
spindle torque
Opis:: Results of friction stir processing (FSP) of aluminium alloy 6082 are presented in this paper. The FSP is an emerging metal working technology that can provide localized modification and control of microstructures in near surface layers of processed metallic components. This technology represents an adaptation of the principle of friction stir welding (FSW), a solid state joining process originally developed at the Welding Institute in the United Kingdom. Investigations were conducted on the welding machine, built on the base of the conventional, vertical milling machine equipped with LOWSTIR device - weld monitoring system plus software to display real time numerical values of forces and torque. The goal of the research was to determine the relationship between processing parameters and quality of the processed surface, forces and spindle torque acting on the tool. Results indicate that the quality of FSP zone is good in the limited range of processing parameters. The increase of the rotation speed of a tool causes the decrease in the spindle torque and increase in the heat generation.
W artykule przedstawiono wyniki badań procesu tarciowej modyfikacji warstw wierzchnich z mieszaniem materiału (ang. friction stir processing - FSP) stopu aluminium 6082. Technologia FSP jest rozwijającą się metodą pozwalającą na lokalne modyfikowanie i kontrolowanie mikrostruktury w warstwach wierzchnich obrabianych materiałów metalowych. Technologia ta opiera się na tych samych zasadach co technologia zgrzewania z mieszaniem materiału zgrzeiny (ang. Friction Stir Welding - FSW), która została opracowana w instytucie spawalnictwa w Wielkiej Brytanii (TWI). Badania zostały przeprowadzone na stanowisku do zgrzewania FSW zbudowanym na bazie konwencjonalnej frezarki wyposażonej w głowicę pomiarową LOWSTIR pozwalającą na pomiar sił i momentu działających na narzędzie w czasie rzeczywistym. Celem prowadzonych badań było poznanie zależności pomiędzy parametrami procesu a jakością modyfikowanych obszarów oraz sił i momentu działających na narzędzie. Wyniki badań wskazują, że w ograniczonym zakresie parametrów modyfikowania można uzyskać dobrą jakość obszarów zmodyfikowanych. Ponadto zauważono, że wzrost prędkości obrotowej narzędzia powoduje zmniejszenie momentu obrotowego oraz wzrost ilości generowanego ciepła.
Źródło:: Archives of Metallurgy and Materials; 2011, 56, 3; 779-788
1733-3490
Pojawia się w:: Archives of Metallurgy and Materials
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Gold catalysts supported on zeolites
Katalizatory złotowe osadzone na zeolitach
Autorzy:: Walkowiak, Adrian
Powiązania:: https://bibliotekanauki.pl/articles/2057912.pdf
Data publikacji:: 2021
Wydawca:: Polskie Towarzystwo Chemiczne
Tematy:: heterogeniczne katalizatory złotowe
nanocząstki złota
zeolity
metody modyfikacji zeolitów złotem
zastosowanie zeolitów modyfikowanych złotem
proces katalityczny
heterogeneous gold catalysts
gold nanoparticles
zeolites
methods of zeolites modification with gold
application of gold-modified zeolites
catalytic process
Opis:: Heterogeneous gold catalysis is a relatively young but dynamically developing field of chemistry. At the end of the 1980s, Masatake Haruta and Graham Hutchings provided experimental evidence of high activity of supported gold catalysts in CO oxidation and acetylene hydrochlorination. Thus, these two researchers challenged the prevailing chemists’ belief that gold is almost completely chemically inert and catalytically inactive. Since then, gold catalysis has been constantly in the centre of attention of a wide array of scientists from around the world. However, there are still many questions about the nature of catalysts containing this noble metal, which inspires in-depth research in this field. From among various potential supports for gold heterogeneous catalysts, zeolites have drawn much attention thanks to several unique properties of this group of materials, among which the most important are high thermal stability and the presence of a system of pores of strictly defined sizes. Zeolites have extremely large surface area, which is desirable to obtain high dispersion of the active phase. The article provides a concise overview of the methods of gold nanoparticles deposition on zeolitic supports and catalytic applications of such materials. The first chapter sheds light on the properties of bulk and nano-sized Au and depicts the background of gold catalysis development. In the following part, a brief description of zeolites and their properties is delivered. The third chapter is devoted entirely to the description of several preparation methods of zeolite-supported gold catalysts and their applications in different catalytic processes. The following post-synthetic methods of zeolite modification with gold are described: impregnation, ion exchange, deposition-reduction, chemical vapour deposition, and grafting. The most important advantages and disadvantages of each method are summarized. The article concludes with a résumé of literature reports concerning the use of zeolitesupported gold catalysts in various processes. Special attention was paid to selective oxidation of alcohols and biomass-derived chemicals (e.g. glucose).
Źródło:: Wiadomości Chemiczne; 2021, 75, 11-12; 1259--1293
0043-5104
2300-0295
Pojawia się w:: Wiadomości Chemiczne
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Influence of Cast Iron Modification on Free Vibration Frequency of Casting
Autorzy:: Konopka, Z.
Łągiewka, M.
Zyska, A.
Powiązania:: https://bibliotekanauki.pl/articles/383158.pdf
Data publikacji:: 2020
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: gray cast iron
modification process
free vibration
casting
vibration frequency of casting
żeliwo szare
proces modyfikacji
drgania swobodne
odlewy
częstotliwość drgań odlewu
Opis:: The paper presents the results of investigations concerning the influence of gray cast iron modification on free vibration frequency of the disc casting. Three different chemical composition melts of gray cast iron were prepared in induction furnace. During gravity casting 0.05% and 0.3% mass of the Inolate modifier was added on stream of metal for changing graphite flakes in castings. Sound signal vibration of cast iron sample was registered by means on microphone for free vibration frequency measurements. Decreasing of free vibration frequency of modified cast iron in comparison with non modified castings was observed. Higher contents of modifier causes more decreasing of free vibration frequency. Cast iron with smaller contents of carbon and silicon have higher free vibration frequency in comparison with eutectic composition cast iron. Hardness of examined cast iron is lower when the more modifier is added during modification process. Free frequency is smaller with smaller Brinell hardness of disc casting. It was concluded that control of free vibration frequency of disc castings by means of chemical composition and modification process can improved comfort and safety of working parts.
Źródło:: Archives of Foundry Engineering; 2020, 20, 1; 23-26
1897-3310
2299-2944
Pojawia się w:: Archives of Foundry Engineering
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Role of tool rotational speed on the tribological characteristics of magnesium based AZ61A/TiC composite developed via friction stir processing route
Autorzy:: Sagar, P.
Handa, A.
Powiązania:: https://bibliotekanauki.pl/articles/367279.pdf
Data publikacji:: 2020
Wydawca:: Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
Tematy:: friction stir processing
AZ61A magnesium alloy
microhardness
wear
proces tarciowej modyfikacji warstw wierzchnich z mieszaniem materiału
FSP
stop magnezu AZ61
mikrotwardość
zużycie
Opis:: Purpose: A new composite material was prepared and Different properties such as hardness and tribological behaviour of the fabricated metal matrix composite (MMC) was investigated and compared with the base AZ61A magnesium alloy. Design/methodology/approach: For the current research work, state-of-the-art technology, Friction stir processing (FSP) was performed to develop magnesium based AZ61A/TiC composite at optimized set of machine parameters. Findings: Increasing tool rotational speed ultimately leads in enhanced hardness, which further gives superior tribological properties as compared to base AZ61A alloy. Wear observations suggests a combination of abrasive and adhesive wear mechanism. Research limitations/implications: More microstructural and mechanical properties can be examined. Practical implications: The idea behind selecting AZ61A is mainly due to its increasing use in bicycle pedals and military equipment’s where at certain places it needs to encounter friction. In this current work, microhardness study and wear behaviour of AZ61A/TiC composite processed via FSP were examined. Originality/value: Paper is completely new and no work has been done till date considering this material and preparing composite with nanoparticles TiC.
Źródło:: Journal of Achievements in Materials and Manufacturing Engineering; 2020, 101, 2; 60-75
1734-8412
Pojawia się w:: Journal of Achievements in Materials and Manufacturing Engineering
Dostawca treści:: Biblioteka Nauki

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