Novi funkcionalni premazi z magnetnimi delci

Mušič, Branka

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Title:	Novi funkcionalni premazi z magnetnimi delci
Authors:	ID Mušič, Branka (Author) ID Venturini, Peter (Mentor) More about this mentor... ID Žnidaršič, Andrej (Comentor)
Files:	DR_Music_Branka_2012.pdf (7,01 MB) MD5: B5831BCC165DD99DF6E83F2F7838B1DD PID: 20.500.12556/dkum/2a4759a9-186d-4ed3-acaf-6ce39e9d6633
Language:	Slovenian
Work type:	Dissertation
Organization:	FKKT - Faculty of Chemistry and Chemical Engineering
Abstract:	Mnogi sodobni materiali s svojimi izboljšanimi ali povsem novimi lastnostmi rešujejo številne probleme in s tem ponujajo dodano vrednost pri uporabi. Razširili so se napredni kompozitni materiali, saj je njihova velika prednost, da lahko njihove lastnosti načrtujemo vnaprej glede na njihovo končno uporabo. Umetno povzročena elektromagnetna sevanja (EMS) povečujejo negativen vpliv EMS na žive organizme. Zato so številne evropske države že pred časom odločile, da ščitijo svoje državljane z nacionalnimi ukrepi (Evropskem Pre-standardu EN 50166-2 – Human exposure to electromagnetic fields – High frequency). Žive organizme, naprave in prostore lahko zaščitimo pred elektromagnetnim sevanjem tako, da ga odbijemo ali absorbiramo. Pri odbojni zaščiti se lahko uporabi tanka plast odbojnega materiala ali barve. Ti materiali so v svetu že znani in razširjeni. Kot posledica odbojne zaščite pa se lahko bistveno poveča število motenj v okolici. Pri absorpcijski zaščiti se odbije le manjši delež upadlega elektromagnetnega sevanja, večji delež preide v material, kjer se absorbira in se pretvori v neškodljivo toplotno energijo. Absorpcijske materiale lahko vključimo na različne načine v strukturne elemente objekta, ki ga želimo zaščititi. Eden izmed možnih načinov za zaščito pred visokimi frekvencami elektromagnetnega sevanja je kompozitno premazno sredstvo, v funkciji absorpcije nezaželenega EMS. Razumevanje procesov v funkcionalnem premazu je strateško gledano izredno pomembno v svetovnem merilu. Možna osnova za absorpcijo kompozitnega premaznega sredstva so magnetni delci. S sintezo v trdnem smo pripravili aktivne delce, katere smo uporabili za premaz s funkcijo absorpcije EMS. To so ferimagnetni MnZn feriti. V doktorskem delu smo raziskali vpliv velikosti MnZn feritnih delcev in vpliv utežne koncentracije MnZn feritnih delcev na elektromagnetne lastnosti kompozita. Del raziskav je bil torej usmerjen v pripravo MnZn ferita z vidika optimizacije tako fizikalnih lastnosti, kot so oblika in velikost delcev ter s tem povezana specifična površina delcev, kemijske sestave in tudi elektromagnetnih parametrov. Pripravili smo sedem različnih velikosti delcev MnZn feritov, najmanjši delci velikosti 3,70 μm in največji delci 14,95 μm. Prikazani rezultati elektromagnetnih lastnosti kompozitov vsebujejo 75 ut.% in 90 ut.% MnZn ferita. Drugi del raziskav pa je bil usmerjen v razvoj kompozitnega premaznega sredstva. Ta del vključuje razvoj tehnološke priprave novega premaza ter testiranje aktivnosti absorpcije elektromagnetnega sevanja v frekvenčnem območju 100 MHz do 10 GHz ustreznih kompozitnih premaznih sistemov. Meritve učinkovitosti absorpcije smo izvedli v odvisnosti od debeline nanosa absorpcijskega premaza, pri 3 mm, 4 mm in 5 mm nanosa. V kompozitnem materialu, ki smo ga razvili, smo združili magnetne vključke in premazni sistem. Razvili smo nov tip premaza, z novo funkcionalnostjo ter nov tip absorberja v obliki kita, ki absorbira v mikrovalovnem področju.
Keywords:	absorberji elektromagnetnega valovanja, premazi, feritni materiali
Place of publishing:	Ljubljana
Publisher:	[B. Mušič]
Year of publishing:	2012
PID:	20.500.12556/DKUM-22406
UDC:	620.197.6-537(043.3)
COBISS.SI-ID:	35856645
NUK URN:	URN:SI:UM:DK:F8MWT6WZ
Publication date in DKUM:	03.04.2012
Views:	3093
Downloads:	316
Metadata:
Categories:	KTFMB - FKKT
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Secondary language

Language:	English
Title:	Incorporation of magnetic materials in coating systems
Abstract:	Many current materials with their improved or completely new properties are being used to solve numerous problems and as such offer additional value in their application. Advanced composite materials have spread, since their large advantage is that their attributes can be plane in advance regarding their final application. Artificially created electromagnetic radiation (EMR) is increasing the negative influence on live organisms. That is why numerous European countries have decided in the past to protect their citizens with national acts (European Pre-standard EN 50166-2 – Human exposure to electromagnetic fields – High frequency). Living organisms, devices and rooms can be protected from electromagnetic radiation by reflecting or absorbing it. With the reflective protection a thin layer of reflecting material or colour can be used. These materials are both known and popular throughout the world. The number of interferences may largely increase in the surrounding area as a result of the reflective protection. But with the absorption protection a lower amount of electromagnetic radiation is reflected and a larger amount of it passes into the material where it is absorbed and converted into unharmful thermal energy. Different absorption materials can be integrated in different ways into individual structure elements of the facility we wish to protect. One of the possible ways of protection from high frequencies of electromagnetic radiation is the use of a composite coating in the function of absorbing undesirable EMR. Understanding the processes of a functional coating is from a strategic viewpoint exceptionally important in a worldwide scale. Magnetic particles are a possible basis for absorption of a composite coating. With a synthesis in a solid we prepared active particles, which we used for a coating with an absorption function of EMR. These are ferromagnetic MnZn ferrites. In doctoral work we researched the influence of the size of MnZn ferrite particles and the influence of weight concentration of MnZn ferrite particles on electromagnetic properties of the composite. As such, part of the research was oriented into the preparation of the MnZn ferrites from the viewpoint of the optimization of physical properties, such as the shape and size of the particles plus related to this the specific area of the particles, chemical properties and also electromagnetic parameters. We prepared the particles of the MnZn ferrites in seven different sizes, the smallest of them measuring 3,70 μm and the largest particles measuring 14,95 μm. The displayed result of the composites’ electromagnetic attributes contains 75 wt.% and 90 wt.% MnZn ferrites. The second part of the research was directed into the development of a composite coating. This part incorporates the development of a technological preparation of a new coating and the testing of the activity of the absorption of electromagnetic radiation in the frequency range of 100 MHz to 10 GHz of the appropriate composite coating systems. The measurements of the efficiency of the absorption were conducted in dependence of the applied width of the absorption coating of 3 mm, 4 mm and 5 mm. In the composite material, which we developed we combined magnetic inclusions with a coating system. We developed a new type of coating with a new functionality and a new type of absorber in the form of a putty, which absorbs in the range of microwaves.
Keywords:	electromagnetic radiation absrobent materials, ferittes, mictowave, coatings

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