20.500.12556/DKUM-41306 RAZVOJ NOVIH KOVINSKIH MATRIC Z IONSKO IN KOVALENTNO VEZANIMI TRDNIMI SNOVMI DEVELOPMENT OF NEW FE-BASE MMC WITH IONIC AND COVALENT BONDED HARD PARTICLES Obraba je glavni krivec za potrato materialov in izgubo njihovih mehanskih lastnosti. Vsako zmanjšanje obrabe materiala lahko vodi do velikih prihrankov. Glavna motivacija te diplomske naloge je razvoj novih kovinskih kompozitov na osnovi Fe. Ti kompoziti so sestavljeni iz kovinske matrice z fino razpršenimi trdimi delci v njeni mikrostrukturi. Cene zlitin na osnovi Ni and Co so visoke, prav tako pa imajo te zlitine toksičen in kancerogen efekt. Trde zlitine na osnovi Fe predstavljajo ekonomsko in ekološko alternativo. Potreba po optimizaciji se lahko pojavi tudi z ozirom na trde delce, ki so vstavljeni v kovinsko matrico. Kot spojina za trdi delec je bil uporabljen kovinsko vezan WC. Zaloge le tega na tržišču so omejene, sočasno pa naraščajo cene te spojine na tržišču. Poleg cene kot pomanjkljivost lahko omenimo raztopitev WC v materialih, ki temeljijo na Fe. V želji, da bi se izognili visokim cenam in omejili raztopitev WC, predstavljajo novi trdi ionsko vezani (SiO2, AlZrO) in kovalentno vezani (SiC) trdi delci zanimivo alternativo. Vzroke, zakaj ti trdi delci niso bili uporabljeni že prej, lahko pripisujemo njihovim lastnostim vezave, ki omejuje vezavo teh trdih delcev v kovinsko matrico. Za izboljšanje njihove vezave je na površino teh delcev nanesena ovojnica s PVD procesom. V primeru ionsko vezanih delcev ta ovojnica spodbuja vezavo delcev v kovinsko matrico, v primeru kovalentno vezanih delcev pa nanesena ovojnica služi kot ovira za raztopitev trdih delcev v materialih, ki temeljijo na Fe. Kovinski kompoziti z vezanimi trdimi delci so proizvedeni s procesom InduClad. V ospredju raziskav so stičišča med trdimi delci in ovojnico, ter ovojnico in kovinsko matrico. Raziskave so bile opravljene z elektronskim in optičnim mikroskopom. Nadalje je raziskana mikrostruktura in obraba proti trdim abrazivom kovinskih kompozitov. Za primerjavo med mikrostrukturo in obrabo delcev so bili vzorci raziskani po standardu ASTM G65. Rezultati so pokazali, da nanos ovojnice na ionsko vezane trde delce (SiO2 , AlZrO) izboljša vezavo delcev v kovinsko matrico in posledično zmanjša obrabo kovinskih kompozitov. Nanos ovojnice na kovalentno vezane delce skoraj popolnoma prepreči raztopitev delcev v kovinskih matricah. Wear is the main cause of material wastages and and loss of mechanical performance. Any reduction of wear can result in considerable savings. The main focus of the diploma thesis is the development of Fe-base MMC. These kind of composite materials are made of a metallic binder matrix with embedded HPs, finely distributed in the microstructure. Fe-base hardfacing alloys represent an economical and ecological alternative to Co- and Ni-base hardfacing alloys, since the prices of Ni- and Co-hardfacing alloys are high, futhermore, they can have toxic and carcinogenic effect. The need for optimatization of MMC can appear also with regard to the HPs embedded into the MM. Conventionally, metallic powders and metallic bonded HP like FTC is used for the production of composite materials. The disadvantages by using FTC can be found in high costs (50kg/EUR) and the FTC-dissolution in Fe-base materials, resulting in the formation of the brittle carbide close to the stoichiometry (Fe3W3)C. Therefore, it makes sense to regard new HP, to produce new MMC with covalent bonded (SiC) and ionic bonded (SiO2, AlZrO) HPs. The reasons, why this HPs were not used prior can be traced back in their bonding behaviour, counteracting the formation of stable phases as a result of reactions between the HP and the MM. To fulfil a good embedding of the HP, an additionally coating, produced with the PVD process is required. In the case of thermal sensitive HPs, a barrier coating protects HP against dissolution. In the case of the ionic bonded HPs the coating enchance the particle embedding and improves the adhesive bonding of the HPs in the MM by formating of more stable phases with the HPs as well as with the MM, respectively. The MMC were produced with the InduClad process. In foreground of the investigations are the interfaces between the HP, the MM and the coatings produced with the PVD process. The interfaces were investigated by means of OM and SEM. Futhermore, the microstructure and the wear resistance of the produced MMC on the construction steel was investigated. The samples were investigated by means of ASTM 65, to compere the microstructure with the wear resistance of the produced MMCs. According to the results, the deposited coating on the ionic bonded HPs (SiO2, AlZrO) improves the embedding of those HP in the MM. The deposited coating on the covalent bonded HPs (SiC) almost completely reduces the dissolution of HP in the MM. Consequelntly the wear resistance is improved. Obraba zlitine na osnovi Fe PVD proces InduClad proces WC AlZrO SiO2 SiC Wear Fe-base MMC PVD process InduClad process FTC AlZrO SiO2 SiC true true false [M. Pori] Slovenski jezik Angleški jezik Diplomsko delo 2013-08-20 23:59:48 2017-08-16 12:11:24 2022-05-04 03:07:09 2021-04-25 03:08:40 2013 0 Maribor 0 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 669.112.2:669.15(043.2) 17496342 URN:SI:UM:DK:3QUCYGZM UNI_Pori_Maja_2013.pdf UNI_Pori_Maja_2013.pdf 1 DB705F682E7A290F9E97CCA4D5D7078E 41cf6bee41a84baaf11d1f9a6fa43a1c0fbcb98ce828c2777e6f32e903d1d0d4 251a83c8-7c0a-11eb-bb7a-00155d0001ca https://dk.um.si/Dokument.php?lang=slv&id=57045 Fakulteta za kemijo in kemijsko tehnologijo 0 0 0